hackandlearn

This blog is based on what I learn in my day-to-day life about coding, technology, hacking and other fun stuff. Some stuff would be my original while some will be taken from the Internet.

[hackandlearn]

The Latest Cult Hero

The Latest Cult Hero -- Dr. J.R. (Bob) Dobbs

By Stephen G. Bloom Dallas Morning News

DALLAS -- First there was the Gilgamesh, then the Bible, the Koran, the Book of Mormon, Dianetics, "I'm OK, You're OK," and now, "The Book of the SubGenius."

Or so says Doug Smith (a.k.a. Ivan Stang) who -- along with three Dallas friends, Lamont Duvoe (Dr. X), John Hagen (Satellite Weavers) and Philo Drummond -- has collected the thoughts of a strange and bizarre messiah, Dr. J.R. (Bob) Dobbs.

Pipe-smoking Dr. Bob, who bears an uncanny resemblance to both Beaver Cleaver's father, Ward, and comic strip hero Mark Trail, may or may not exist. But thatti snot important says Smith, 30.

"Dr. Bob is too busy to be interviewed," Smith says defiantly. "He's off communing with the elder gods of the universe."

Dobbs is the leader of a New Wave cult group called the SubGenius, whose principles first were espoused in a 1978 pamphlet that has become an underground classic. The Dallas-based cult's newest offering is the best-selling "Book of the SubGenius" (MacGraw-Hill, $9.95).

The transition from pamphlet to a professionally produced book wasn't anything planned by Smith and the rest of Dobbs' disciples. Last year, McGraw-Hill contacted Smith with a book offer after one of its editors had been slipped the pamphlet at a company picnic. That, along with news of the peculiar First World SubGenius Convention actually held at Dealey Plaza on Nov. 22, 1981 was enough for publishers to think money could be made by spreading Dr. Bob's gospel.

Smith hired a Chicago agent he describes as a "very sane, 50-year-old woman not addicted to drugs or anything," who started a bidding war for the book, which doubled the hefty advance money. McGraw-Hill's Tim McGuiness sold the publishing company's marketing division on the idea of the book.

"I had this gut feeling it would do well," he says. "Word-of-mouth advertising that this was a comic, underground satire has sold the book for us. Not everyone picks up on the spoof. It's on a frequency only dogs and select humans can hear."

Enough people have bought Bob's 184-page philosophy for MacGraw-Hill to commission a second printing only five weeks after the book was released -- highly unusual for a first book written by an unknown.

But then again, Bob and his disciples are not very usual. One has to have watched the "Addams Family" to appreciate the strangeness of Dr. Bob's world headquarters, Smith's East Dallas home. Vintage comic books are stacked on a stand in the living room; posters of Idi Amin and Captain Beefheart decorate the upstairs; a green and red papier-mache dinosaur decorates the foyer.

Meanwhile, Smith's wife, Shelby, a petite woman wearing a skimpy purple bikini, extols the virtues of broccoli to their two young children, who wander around the house naked.

Smith, who wrote most of the book and is probably the most knowledgeable of Dr. Bob's scribes, graduated 12 years ago from St. Mark's School, which he calls "one of the conspiracy's (translation: establishment's) most important bastions, composed of twisted and bizarre minds."

He became an independent film maker in Dallas, doing animated wacko movies. His most celebrated, shown in art houses throughout the United States: "Reproduction Cycle," a 15-minute short about sex among microbes on Mars, and "Let's Visit the World of the Future," an X-rated, punk travelogue.

By April, 1978, Smith and his cohorts had cooked up the idea of writing about Dr. Bob. As Dallas journalist David Seeley, who has followed the cult's mysterious exploits since its beginning, has written, "People out there were watching 'Laverne and Shirley,' reading Reader's Digest and chewing 32 times before swallowing, and it seemed to Drummond, Smith and Duvoe that they were the only ones who knew how screwed up the world really was."

The three began collecting pamphlets from UFO cults, Atlantis aficionados, John Birch Society chapters, Scientology freaks, white supremacy groups and Hare Krishna devotees. "We realized it would be easy to mmx them up in one pile and come out with something better," Smith says.

Whether the world was ready or not, Dr. Bob was introduced through an appropriately demented, 16-page pamphlet. His disciples sold the pamphlet for $1, recommending that converts spread the gospel by leaving it in laundromats and restrooms.

But just who is Dr. J.R. (Bob) Dobbs, the man with that obnoxiously self-assured smile?

Only this much is known: Bob is about 60 years old. His father was a Mayan pharmacist, his mother the relative of an Irish revolutionary. Bob became a millionaire at age 6, and while in high school received a degree in law through a correspondence course. He did top-secret intelligence work during World War II, then became an author (his 'Sleeping for Fitness' was a best seller). Finally, he went into business and became an awning salesman extraordinaire.

He leads a motley assemblage of family: wife, Connie (his first-grade sweetheart), his five sons (Bubba, Bobby Jr., Adam Kadman, Shem and Shaun) and his daughter (her name has never been released for fear of her being kidnapped).

Bob, his disciples say, is everywhere. "He might be infiltrating the Austral Plane(CQ) or be on Skid Row giving a bum a haircut or tumbling in bed, extracting secrets from some conspiracy wench," according to "The Book of the SubGenius."

What has garnered such a following for Dr. Bob is his carefree philosophy, which is a cross between Alfred E. Newman's and Ozzy Osbourne's.

His motto is "Slack off!" which translates to doing what you want to do whenever you want to do it. "The world is a turkey," according to "The Book of the SubGenius," "and Bob gives you the carving knife."

No religion would be complete without a prescribed death ritual. Bob's recommendations are not for the queasy. "The great honor for any SubGenius is to have his head mounted on Bob's rumpus room wall, or his skull made into one of Dobbs' ritual ashtrays. Give of yourself and you will be assured of special treatment on The Other Side."

Interested readers who wish to become Dr. Bob devotees should know how to salute fellow parishioners. Put an index finger to the throat, run it up and down over the Adam's apple fast and gurgle "EYIYIYI."

Actual churches of Dr. Bob followers have been established. Active congregations exist in New York, Chicago, San Franccsco, Austin, Minneapolis and Boston -- but not in Dallas. "It's too straight a city," says Smith.

In Berkeley, there is even a weekly Dr. Bob radio show. Scribe Smith estimates about 30,000 followers adhere to the cult.

Abandoned 1950's motels, gas stations and hamburger stands are recommended as potential sites of worship. Typical Dr. Bob ceremonies start with congregants screaming at the top of their lungs, followed by a general pelting of the self-ordained minister with coins. The donations are not tax-deductible, however; the SubGenius Foundation is a profit-making business incorporated within Dallas County. Even Dr. Bob's face is protected with a registered trademark.

All the writing of "The Book of the SubGenius," as well as most of the production work, was accomplished at Smith's house. It took six months to complete the manuscript for McGraw-Hill.

The last thing Smith wants is for the cult to be swallowed up by an egocentric leader. "If we get too big, were going to have to kill Bob. I'd hate to do it. But he doesn't need the money. I want it."

[hackandlearn]

Showdown over computer ‘crime’

Article reprinted from STATES NEWS SERVICE, August 5, 1990

Author: Brooks Boliek

Showdown over computer 'crime'

Some of the nation's computer pioneers see the digital world in which they toil as a cybernetic rangeland with its own kind of frontier justice. And some of them have set out to change the system.

Their rallying cry is Operation Sun Devil and other government probes into malfeasance by so-called computer "hackers." These investigations, they assert, smack of hang-em-high justice and all to often become examples of government heavy-handedness.

"Some of the government's actions clearly weren't constitutional," said Mitch Kapor, founder of Lotus Development Corp. and a new software firm ON Technology in Cambridge, Mass.

Kapor, along with a small group of fellow computer pioneers, recently announced the formation of the Electronic Frontier Foundation, a group dedicated to protecting the rights of computer users. Its ultimate goal is to extend the same First Amendment protection that the print and broadcast media enjoy to digital communications.

"Our idea is to get people to understand the issues and not to try and make decisions in a controversial and confrontational atmosphere," Kapor said.

Secret Service and U.S. Justice Department spokesmen in Washington declined to comment on Operation Sun Devil or other computer investigations. But they stressed that the federal agencies are mindful of the need to protect civil rights.

"We are not just some renegade agency breaking into peoples's computer systems,"said Secret Service Agent Rich Adams. "We would not be investigating if we were not mandated by Congress. That's why we're involved."

The foundation is pushing its goals by providing legal assistance to computer users who become victims of what they see as overly zealous law enforcement officials. It also is awarding grants to civil liberties organizations such as the Computer Professionals for Social Responsibility in Palo Alto.

Kapor stresses that the foundation is not a defense fund for "hackers" and does not support breaking into computer systems or pirating software.

The foundation has already had an impact. It recently located defense witnesses in the government's case against computer bulletin board operator and newsletter publisher Craig Neidorf. On July 27, in the middle of the trial, the government abruptly dropped its case against Neidorf.

Neidorf was accused of interstate transportation of a stolen BellSouth Corp. document describing its emergency 911 system, a charge which stems from the government's investigation into a group of hackers called the Legion of Doom.

Prosecutors dropped Neidorf's case when Sheldon Zenner, Neidorf's attorney, showed that the information which BellSouth alleged was proprietary could be purchased by calling an 800 number and paying $13.

'Private police force' Terry Gross, an attorney that aided Neidorf's defense team, accused the government of serving as a private police force for large corporations.

"I think it is a very serious concern that we should all have of the government being used as a private police force for private corporations," Gross said. "Especially when BellSouth made a claim that the government accepted."

The foundation contends that prosecutors, policemen and judges must think of computer communications in the same way they think of printed and broadcast communications.

In the eyes of foundation leaders, their main opponent is the federal government. Operation Sun Devil, a two-year investigation, has so far resulted in seven arrests and some 40 computers and 23,000 disks of data.

Kapor's group draws a parallel between the Pentagon Papers case, which involved classified government papers documenting the history of U.S. involvement in Vietnam, and Neidorf's. If Neidorf had published the document in a newspaper, as The New York Times and The Washington Post published the Pentagon Papers, he would have been protected.

"The example they use is a good one," said Ken Wasch, executive director of the Software Publishers Association. If someone printed a document on how to get into a federal facility there would be no restrictions on publication, he explained. "But if you put it on a (computer) bulletin board there would be."

Complex issues Kapor said the Secret Service, the lead investigating agency for computer crimes, as well as the FBI and prosecutors often fail to understand the complex issues that arise with computer crimes. He said law enforcement officers are like most people when it comes to computers: uninformed.

Kapor believes that people are afraid of computers because they don't understand them. To minimize the misunderstanding, the foundation wants to educate law enforcement officers, judicial officers and the public about digital communications.

"There is a hugh gap between where most of us regular folk are today and where the technology is," Kapor said.

Feds claim expertise Secret Service agent Adams disputed the notion that federal officials lack computer expertise. The service has been investigating computer crimes since 1984, he said.

"I think it's just the opposite is true," Adams said. "We are very effective in our investigations and if we didn't have the expertise we wouldn't be as effective."

Adams acknowledged that a lack of manpower means his agency must pick and choose what to investigate.

"They (the EFF) would lead you to believe that we are out there cracking everyone's computer system and looking into every bulletin board," he said. "We simply do not have the manpower to do that. We pinpoint the large dollar losses and those are the ones we investigate."

At least one member of Congress has expressed some concern over the government's crackdown on computer crime. Sen. Patrick Leahy, D-Vt., wants to change the Computer Fraud and Abuse Act of 1986 to prevent the government from going too far. Neidorf was indicted under the law.

"As far as I can tell all he did was republish a document in Phrack (his newsletter)," Leahy said during a hearing on the issue. "That's not a heck of a lot different than someone walking down the street who picks up a document and writes a letter to the editor."

The Neidorf case has disturbed Leahy, who said he is face with the nettlesome problem of balancing the need for computer security with individual rights.

"We know people work very hard to create products with their computers," he said. "They ought to be able to protect those. At the same time, I don't want to see the mass resources of the United States Justice Department turned loose on things that don't make that much difference."

[hackandlearn]

Android Terminal Commands

cat - look at, modify, or combine a file. You can also copy files with this command by "reading" it to another file instead of to the screen.

cd - change from one directory to another

cp - Copy a file from one location to another

dd - copies exact locations to other locations. Can be an entire drive, a folder, etc.

dd if= of=. uses an input file and an output file.

exit - exits the shell you are in. When you type su you start up a shell.

ls - lists all files with in a directory try ls - l too.

mv - Move a file from one location to another. At the same time you can rename a file.

su - Substitute User. We type this to switch to the root user. You need to type this command first to do a lot of the other commands.

tar - creates taped archives. Compresses files like winzip, 7zip, winrar and others tar /? for details. rm - followed by a file name with delete the file sync - synchronizes any data on disk with data in memory. We type this before rebooting to ensure we've got all data written

Other commands of interest:

df - how much free disk space. In linux you can add a switch "df -h" but the "-h" does nothing for me on Android. top - like task manager, it displays running processes. in Linux the q key quits. On Android I don't know how to make it quit other than closing the app. uptime - displays how long it has been since you last rebooted the system.

busybox - a tool that combines many linux commands into a single compact file. Typing this displays all the commands at your disposal.

busybox df - a much easier to read display of free diskspace. This display shows how full (use%) each file system is.

[hackandlearn]

IBM AS/400 Command Summary

Command Description

ADDACC Add Access Code ADDAJE Add Autostart Job Entry ADDAUTLE Add Authorization List Entry ADDBKP Add Breakpoint ADDCFGLE Add Configuration List Entries ADDCMNE Add Communications Entry ADDDIRE Add Directory Entry ADDDLOAUT Add DLO Authority ADDDSTLE Add Distribution List Entry ADDDTADFN Add Data Definition ADDICFDEVE Add ICF Device Entry ADDJOBQE Add Job Queue Entry ADDLFM Add Logical File Member ADDLIBLE Add Library List Entry ADDMSGD Add Message Description ADDNETJOBE Add Network Job Entry ADDPFM Add Physical File Member ADDPFVLM Add Phy File Variable Len Mbr ADDPGM Add Program ADDRPYLE Add Reply List Entry ADDRTGE Add Routing Entry ADDTRC Add Trace ADDWSE Add Work Station Entry ALCOBJ Allocate Object ANSLIN Answer Line ANSQST Answer Questions ANZACCGRP Analyze Process Access Group ANZDBF Analyze Database Files ANZDBFKEY Analyze Database File Keys ANZPGM Analyze Programs ANZPRB Analyze Problem ANZS34OCL Analyze S/34 OCL APYJRNCHG Apply Journaled Changes APYPTF Apply Program Temporary Fix ASKQST Ask Question BCHJOB Batch Job CALL Call Program CFGDSTSRV Configure Distribution Service CHGACGCDE Change Accounting Code CHGAJE Change Autostart Job Entry CHGAUTLE Change Authorization List Entr CHGCFGL Change Configuration List CHGCMD Change Command CHGCMDDFT Change Command Default CHGCMNE Change Communications Entry CHGCOSD Change Class-of-Service Desc CHGCTLAPPC Change Ctl Desc (APPC) CHGCTLASC Change Ctl Desc (Async) CHGCTLBSC Change Ctl Desc (BSC) CHGCTLFNC Change Ctl Desc (Finance) CHGCTLHOST Change Ctl Desc (SNA Host) CHGCTLLWS Change Ctl Desc (Local WS) CHGCTLRWS Change Ctl Desc (Remote WS) CHGCTLVWS Change Ctl Desc (Virtual WS) CHGCURLIB Change Current Library CHGDBG Change Debug CHGDDMF Change DDM File CHGDEVAPPC Change Device Desc (APPC) CHGDEVASC Change Device Desc (Async) CHGDEVBSC Change Device Desc (BSC) CHGDEVDKT Change Device Desc (Diskette) CHGDEVDSP Change Device Desc (Display) CHGDEVFNC Change Device Desc (Finance) CHGDEVHOST Change Device Desc (SNA Host) CHGDEVPRT Change Device Desc (Printer) CHGDEVSNUF Change Device Desc (SNUF) CHGDEVTAP Change Device Desc (Tape) CHGDIRE Change Directory Entry CHGDKTF Change Diskette File CHGDLOAUT Change DLO Authority CHGDLOOWN Change DLO Owner CHGDOCD Change Document Description CHGDSPF Change Display File CHGDSTPWD Change DST Password CHGDTA Change Data CHGDTAARA Change Data Area CHGGRPA Change Group Attributes CHGHLLPTR Change HLL Pointer CHGICFDEVE Change ICF Device Entry CHGICFF Change ICF File CHGJOB Change Job CHGJOBD Change Job Description CHGJOBQE Change Job Queue Entry CHGJOBTYP Change Job Type CHGJRN Change Journal CHGKBDMAP Change Keyboard Map CHGLF Change Logical File CHGLFM Change Logical File Member CHGLIB Change Library CHGLIBL Change Library List CHGLINASC Change Line Desc (Async) CHGLINBSC Change Line Desc (BSC) CHGLINSDLC Change Line Desc (SDLC) CHGLINTDLC Change Line Desc (TDLC) CHGLINTRN Change Line Desc (Token-Ring) CHGLINX25 Change Line Desc (X.25) CHGMNU Change Menu CHGMODD Change Mode Description CHGMSGD Change Message Description CHGMSGQ Change Message Queue CHGNETA Change Network Attributes CHGNETJOBE Change Network Job Entry CHGOBJD Change Object Description CHGOBJOWN Change Object Owner CHGOUTQ Change Output Queue CHGPCOPRF Change PC Organizer Profile CHGPF Change Physical File CHGPFM Change Physical File Member CHGPGM Change Program CHGPGMVAR Change Program Variable CHGPRF Change Profile CHGPRTF Change Printer File CHGPTR Change Pointer CHGPWD Change Password CHGQSTDB Change Q/A Database CHGRPYLE Change Reply List Entry CHGRTGE Change Routing Entry CHGSAVF Change Save File CHGSBSD Change Subsystem Description CHGSPLFA Change Spooled File Attributes CHGSRCPF Change Source Physical File CHGSSNMAX Change Session Maximum CHGSYSLIBL Change System Library List CHGSYSVAL Change System Value CHGS34LIBM Change S/34 Library Member CHGS36 Change S/36 Configuration CHGS36PGMA Change S/36 Program Attributes CHGS36PRCA Change S/36 Proc Attributes CHGS36PRCX Change S/36 Proc Attributes CHGS36SRCA Change S/36 Source Attributes CHGTAPF Change Tape File CHGUSRPRF Change User Profile CHGVAR Change Variable CHGWSE Change Work Station Entry CHGWTR Change Writer CHKDKT Check Diskette CHKDOC Check Document CHKOBJ Check Object CHKPWD Check Password CHKRCDLCK Check Record Locks CHKTAP Check Tape CLCSTGCFG Calculate Storage Config CLOF Close File CLRDKT Clear Diskette CLRJOBQ Clear Job Queue CLRLIB Clear Library CLRMSGQ Clear Message Queue CLROUTQ Clear Output Queue CLRPFM Clear Physical File Member CLRSAVF Clear Save File CLRTRCDTA Clear Trace Data CMD Command Definition CMPJRNIMG Compare Journal Images COMMIT Commit CPYCFGL Copy Configuration List CPYDOC Copy Document CPYF Copy File CPYFRMDKT Copy From Diskette CPYFRMPCD Copy From PC Document CPYFRMTAP Copy From Tape CPYLIB Copy Library CPYPTF Copy Program Temporary Fix CPYSPLF Copy Spooled File CPYSRCF Copy Source File CPYTODKT Copy To Diskette CPYTOPCD Copy To PC Document CPYTOTAP Copy To Tape CRTAPAR Create APAR CRTAUTHLR Create Authority Holder CRTAUTL Create Authorization List CRTBASPGM Create BASIC Program CRTCBLPGM Create COBOL Program CRTCFGL Create Configuration List CRTCLPGM Create CL Program CRTCLS Create Class CRTCMD Create Command CRTCOSD Create Class-of-Service Desc CRTCTLAPPC Create Ctl Desc (APPC) CRTCTLASC Create Ctl Desc (Async) CRTCTLBSC Create Ctl Desc (BSC) CRTCTLFNC Create Ctl Desc (Finance) CRTCTLHOST Create Ctl Desc (SNA Host) CRTCTLLWS Create Ctl Desc (Local WS) CRTCTLRWS Create Ctl Desc (Remote WS) CRTCTLVWS Create Ctl Desc (Virtual WS) CRTDDMF Create DDM File CRTDEVAPPC Create Device Desc (APPC) CRTDEVASC Create Device Desc (Async) CRTDEVBSC Create Device Desc (BSC) CRTDEVDKT Create Device Desc (Diskette) CRTDEVDSP Create Device Desc (Display) CRTDEVFNC Create Device Desc (Finance) CRTDEVHOST Create Device Desc (SNA Host) CRTDEVPRT Create Device Desc (Printer) CRTDEVSNUF Create Device Desc (SNUF) CRTDEVTAP Create Device Desc (Tape) CRTDKTF Create Diskette File CRTDOC Create Document CRTDSPF Create Display File CRTDSTL Create Distribution List CRTDTAARA Create Data Area CRTDTADCT Create Data Dictionary CRTDTAQ Create Data Queue CRTDUPOBJ Create Duplicate Object CRTEDTD Create Edit Description CRTFLR Create Folder CRTGSS Create Graphics Symbol Set CRTICFF Create ICF File CRTJOBD Create Job Description CRTJOBQ Create Job Queue CRTJRN Create Journal CRTJRNRCV Create Journal Receiver CRTLF Create Logical File CRTLIB Create Library CRTLINASC Create Line Desc (Async) CRTLINBSC Create Line Desc (BSC) CRTLINSDLC Create Line Desc (SDLC) CRTLINTDLC Create Line Desc (TDLC) CRTLINTRN Create Line Desc (Token-Ring) CRTLINX25 Create Line Desc (X.25) CRTMNU Create Menu CRTMODD Create Mode Description CRTMSGF Create Message File CRTMSGFMNU Create Menu from Msg Files CRTMSGQ Create Message Queue CRTOUTQ Create Output Queue CRTPF Create Physical File CRTPLIPGM Create PL/I Program CRTPRTF Create Printer File CRTQSTDB Create Q/A Database CRTQSTLOD Create Q/A Database Load CRTRPGPGM Create RPG III Program CRTRPTPGM Create Auto Report RPG Program CRTSAVF Create Save File CRTSBSD Create Subsystem Description CRTSPADCT Create Spelling Aid Dictionary CRTSRCPF Create Source Physical File CRTS36CBL Create S/36 COBOL Program CRTS36DSPF Create S/36 Display File CRTS36MNU Create S/36 Menu CRTS36MSGF Create S/36 Message File CRTS36RPG Create RPG II Program CRTS36RPGR Create Console Display File CRTS36RPT Create S/36 RPG II Auto Report CRTTAPF Create Tape File CRTTBL Create Table CRTUSRPRF Create User Profile CVTBASSTR Convert S/36 Stream File CVTBASUNF Convert S/36 Unformatted File CVTBGUDTA Convert BGU Data CVTCLSRC Convert CL Source CVTDAT Convert Date CVTS36CFG Convert S/36 Configuration CVTS36FCT Convert Forms Control Table CVTS36JOB Convert S/36 Migration Job CVTS36QRY Convert S/36 Query CVTS38JOB Convert S/38 Migration Job CVTTOFLR Convert To Folder DATA Data DCL Declare CL Variable DCLF Declare File DEP Dependent Definition DLCOBJ Deallocate Object DLTAUTHLR Delete Authority Holder DLTAUTL Delete Authorization List DLTCFGL Delete Configuration List DLTCHTFMT Delete Chart Format DLTCLS Delete Class DLTCMD Delete Command DLTCOSD Delete Class-of-Service Desc DLTCTLD Delete Controller Description DLTDEVD Delete Device Description DLTDFUPGM Delete DFU Program DLTDKTLBL Delete Diskette Label DLTDLO Delete Document Library Object DLTDOCL Delete Document List DLTDST Delete Distribution DLTDSTL Delete Distribution List DLTDTAARA Delete Data Area DLTDTADCT Delete Data Dictionary DLTDTAQ Delete Data Queue DLTEDTD Delete Edit Description DLTF Delete File DLTGSS Delete Graphic Symbol Set DLTJOBD Delete Job Description DLTJOBQ Delete Job Queue DLTJRN Delete Journal DLTJRNRCV Delete Journal Receiver DLTLIB Delete Library DLTLICPGM Delete Licensed Program DLTLIND Delete Line Description DLTMNU Delete Menu DLTMODD Delete Mode Description DLTMSGF Delete Message File DLTMSGQ Delete Message Queue DLTNETF Delete Network File DLTOUTQ Delete Output Queue DLTOVR Delete Override DLTOVRDEVE Delete Override Pgm Dev Entry DLTPGM Delete Program DLTPNLGRP Delete Panel Group DLTPRB Delete Problem DLTQRY Delete Query DLTQST Delete Questions and Answers DLTQSTDB Delete Q/A Database DLTSBSD Delete Subsystem Description DLTSCHIDX Delete Search Index DLTSPADCT Delete Spelling Aid Dictionary DLTSPLF Delete Spooled File DLTTBL Delete Table DLTUSRPRF Delete User Profile DLYJOB Delay Job DMPCLPGM Dump CL Program DMPJOB Dump Job DMPJOBINT Dump Job Internal DMPOBJ Dump Object DMPSYSOBJ Dump System Object DMPTAP Dump Tape DMPTRC Dump Trace DO Do Group DSPACC Display Access Code DSPACCAUT Display Access Code Authority DSPACCGRP Display Access Group DSPAPPNINF Display APPN Information DSPAUTHLR Display Authority Holder DSPAUTL Display Authorization List DSPAUTLDLO Display Authorization List DLO DSPAUTLOBJ Display Authorization List Obj DSPAUTUSR Display Authorized Users DSPBKP Display Breakpoints DSPCFGL Display Configuration List DSPCHT Display Chart DSPCLS Display Class DSPCMD Display Command DSPCOSD Display Class-of-Service Desc DSPCTLD Display Controller Description DSPDBG Display Debug DSPDBR Display Data Base Relations DSPDDMF Display DDM File DSPDEVD Display Device Description DSPDIR Display Directory DSPDKT Display Diskette DSPDLOAUT Display DLO Authority DSPDOC Display Document DSPDSTL Display Distribution List DSPDSTLOG Display Distribution Log DSPDSTSRV Display Distribution Services DSPDTA Display Data DSPDTAARA Display Data Area DSPDTADCT Display Data Dictionary DSPEDTD Display Edit Description DSPFD Display File Description DSPFFD Display File Field Description DSPFLR Display Folder DSPGDF Display Graphics Data File DSPHLPDOC Display Help Document DSPJOB Display Job DSPJOBD Display Job Description DSPJOBLOG Display Job Log DSPJRN Display Journal DSPJRNRCVA Display Journal Receiver Atr DSPKBDMAP Display Keyboard Map DSPLIB Display Library DSPLIBL Display Library List DSPLIND Display Line Description DSPLOG Display Log DSPMNUA Display Menu Attributes DSPMODD Display Mode Description DSPMODSTS Display Mode Status DSPMSG Display Messages DSPMSGD Display Message Description DSPNETA Display Network Attributes DSPOBJAUT Display Object Authority DSPOBJD Display Object Description DSPOVR Display Override DSPPFM Display Physical File Member DSPPGM Display Program DSPPGMADP Display Program Adopt DSPPGMREF Display Program References DSPPGMVAR Display Program Variable DSPPTF Display Program Temporary Fix DSPRCDLCK Display Record Locks DSPSAVF Display Save File DSPSBSD Display Subsystem Description DSPSOCSTS Display Sphere of Control Sts DSPSPLF Display Spooled File DSPSRVSTS Display Service Status DSPSYSVAL Display System Value DSPS36 Display S/36 Configuration DSPTAP Display Tape DSPTRC Display Trace DSPTRCDTA Display Trace Data DSPUSRPMN Display User Permission DSPUSRPRF Display User Profile DUPDKT Duplicate Diskette EDTAUTL Edit Authorization List EDTDLOAUT Edit DLO Authority EDTDOC Edit Document EDTLIBL Edit Library List EDTOBJAUT Edit Object Authority EDTQST Edit Questions and Answers EDTS36PGMA Edit S/36 Program Attributes EDTS36PRCA Edit S/36 Procedure Attributes EDTS36SRCA Edit S/36 Source Attributes EJTEMLOUT Eject Emulation Output ELEM Element Definition ELSE Else EMLPRTKEY Emulate Printer Keys ENDBCHJOB End Batch Job ENDCBLDBG End COBOL Debug ENDCMTCTL End Commitment Control ENDCPYSCN End Copy Screen ENDCTLRCY End Controller Recovery ENDDBG End Debug Mode ENDDEVRCY End Device Recovery ENDDO End Do Group ENDGRPJOB End Group Job ENDINP End Input ENDJOB End Job ENDJOBABN End Job Abnormal ENDJOBTRC End Job Trace ENDJRNAP End Journal Access Path ENDJRNPF End Journaling PF Changes ENDLINRCY End Line Recovery ENDMOD End Mode ENDPASTHR End Pass-Through ENDPFRMON End Performance Monitor ENDPGM End Program ENDPRTEML End Printer Emulation ENDRCV End Receive ENDRDR End Reader ENDRQS End Request ENDSAM End Sampled Address Monitor ENDSAMCOL End SAM Data Collection ENDSBS End Subsystem ENDSRVJOB End Service Job ENDSYS End System ENDS36 End S/36 Session ENDTIESSN End TIE Session ENDWTR End Writer EXTPGMINF Extract Program Information FILDOC File Document FMTDTA Reformat Data GENS36RPT Generate Migration Reports GENS38RPT Generate Migration Reports GO Go to Menu GOTO Go To GRTACCAUT Grant Access Code Authority GRTOBJAUT Grant Object Authority GRTUSRAUT Grant User Authority GRTUSRPMN Grant User Permission HLDCMNDEV Hold Communications Device HLDJOB Hold Job HLDJOBQ Hold Job Queue HLDOUTQ Hold Output Queue HLDRDR Hold Reader HLDSPLF Hold Spooled File HLDWTR Hold Writer IF If INZDKT Initialize Diskette INZPCS Initialize AS/400 PC Support INZPFM Initialize Physical File Mbr INZTAP Initialize Tape LNKDTADFN Link/Unlink Data Definition LODPTF Load Program Temporary Fix LODQSTDB Load Q/A Database MDLSYS Model System MGRS36ITM Migrate item MGRS38OBJ Migrate object MONMSG Monitor Message MOVOBJ Move Object MRGDOC Merge Document MRGFORMD Merge Form Description MRGMSGF Merge Message File OPNDBF Open Data Base File OPNQRYF Open Query File OVRDBF Override with Data Base File OVRDKTF Override with Diskette File OVRDSPF Override with Display File OVRICFDEVE Override ICF Pgm Device Entry OVRICFF Override ICF File OVRMSGF Override Message File OVRPRTF Override with Printer File OVRSAVF Override with Save File OVRTAPF Override with Tape File PAGDOC Paginate Document PARM Parameter Definition PGM Program PMTCTL Prompt Control Definition POSDBF Position Data Base File PRTCMDUSG Print Command Usage PRTCPTRPT Print Component Report PRTDOC Print Document PRTERRLOG Print Error Log PRTINTDTA Print Internal Data PRTJOBTRC Print Job Trace PRTLCKRPT Print Lock Report PRTSAMDTA Print SAM Data PRTSYSRPT Print System Report PRTTNSRPT Print Transaction Report PWRDWNSYS Power Down System QRYDOCLIB Query Document Library QRYDST Query Distributions QRYTIEF Query TIE Files QUAL Qualifier Definition RCLDDMCNV Reclaim DDM Conversations RCLDLO Reclaim Document Lib Object RCLRSC Reclaim Resources RCLSTG Reclaim Storage RCVDST Receive Distribution RCVF Receive File RCVJRNE Receive Journal Entry RCVMSG Receive Message RCVNETF Receive Network File RCVTIEF Receive TIE File RETURN Return RGZPFM Reorganize Physical File Mbr RLSCMNDEV Release Communications Device RLSJOB Release Job RLSJOBQ Release Job Queue RLSOUTQ Release Output Queue RLSRDR Release Reader RLSSPLF Release Spooled File RLSWTR Release Writer RMVACC Remove Access Code RMVAJE Remove Autostart Job Entry RMVAUTLE Remove Auth List Entry RMVBKP Remove Breakpoint RMVCFGLE Remove Cfg List Entries RMVCMNE Remove Communications Entry RMVDIRE Remove Directory Entry RMVDLOAUT Remove DLO Authority RMVDSTLE Remove Distribution List Entry RMVICFDEVE Remove ICF Device Entry RMVJOBQE Remove Job Queue Entry RMVJRNCHG Remove Journaled Changes RMVLIBLE Remove Library List Entry RMVM Remove Member RMVMSG Remove Message RMVMSGD Remove Message Description RMVNETJOBE Remove Network Job Entry RMVPGM Remove Program RMVPTF Remove Program Temporary Fix RMVRPYLE Remove Reply List Entry RMVRTGE Remove Routing Entry RMVTRC Remove Trace RMVWSE Remove Work Station Entry RNMDKT Rename Diskette RNMDLO Rename Document Library Object RNMM Rename Member RNMOBJ Rename Object ROLLBACK Rollback RPLDOC Replace Document RRTJOB Reroute Job RSMBKP Resume Breakpoint RSMCTLRCY Resume Controller Recovery RSMDEVRCY Resume Device Recovery RSMLINRCY Resume Line Recovery RSTAUT Restore Authority RSTCFG Restore Configuration RSTDLO Restore Document Lib Object RSTLIB Restore Library RSTLIBS RESTORE/CLEAR 1 TO 10 LIBRARIES RSTLIBSBOS Restore/Clear 1 to 20 libraries RSTLICPGM Restore Licensed Program RSTOBJ Restore Object RSTS36F Restore S/36 File RSTS36FLR Restore S/36 Folder RSTS36LIBM Restore S/36 Library Members RSTUSRPRF Restore User Profiles RTVAUTLE Retrieve Auth List Entry RTVCLSRC Retrieve CL Source RTVDOC Retrieve Document RTVDTAARA Retrieve Data Area RTVGRPA Retrieve Group Attributes RTVJOBA Retrieve Job Attributes RTVJRNE Retrieve Journal Entry RTVMSG Retrieve Message RTVNETA Retrieve Network Attributes RTVSYSVAL Retrieve System Value RTVUSRPRF Retrieve User Profile RUNQRY Run Query RVKACCAUT Revoke Access Code Authority RVKOBJAUT Revoke Object Authority RVKUSRPMN Revoke User Permission SAVCHGOBJ Save Changed Objects SAVDLO Save Document Library Object SAVLIB Save Library SAVLICPGM Save Licensed Program SAVOBJ Save Object SAVSAVFDTA Save Save File Data SAVSYS Save System SAVS36F Save S/36 File SAVS36LIBM Save S/36 Library Members SBMDBJOB Submit Data Base Jobs SBMDKTJOB Submit Diskette Jobs SBMFNCJOB Submit Finance Job SBMJOB Submit Job SBMNETJOB Submit Network Job SBMRMTCMD Submit Remote Command SETATNPGM Set Attention Program SETKBDMAP Set Keyboard Map SETPGMINF Set Program Information SIGNOFF Sign Off SLTCMD Select Command SNDBRKMSG Send Break Message SNDDOC Send Document SNDDST Send Distribution SNDF Send File SNDJRNE Send Journal Entry SNDMSG Send Message SNDNETF Send Network File SNDNETMSG Send Network Message SNDNETSPLF Send Network Spool File SNDPGMMSG Send Program Message SNDPTFORD Send PTF Order SNDRCVF Send/Receive File SNDRPY Send Reply SNDSRVRQS Send Service Request SNDTIEF Send TIE File SNDUSRMSG Send User Message STRAPF Advanced Printer Function STRBAS Start BASIC Session STRBASPRC Start BASIC Procedure STRBGU Start BGU STRCBLDBG Start COBOL Debug STRCMTCTL Start Commitment Control STRCPYSCN Start Copy Screen STRDBG Start Debug STRDBRDR Start Data Base Reader STRDFU Start DFU STRDKTRDR Start Diskette Reader STRDKTWTR Start Diskette Writer STREDU Start Education STREML3270 Start 3270 Display Emulation STRIDD Start IDD STRIDXSCH Start Index Search STRITF Start ITF STRJOBTRC Start Job Trace STRJRNAP Start Journal Access Path STRJRNPF Start Journal Physical File STRMOD Start Mode STROFC Start Office STRPASTHR Start Pass-Through STRPCCMD Start PC Command STRPCO Start PC Organizer STRPDM Start PDM STRPFRMON Start Performance Monitor STRPFRT Start Performance Tools STRPGMMNU Start Programmer Menu STRPRTEML Start Printer Emulation STRPRTWTR Start Printer Writer STRQRY Start Query STRQST Start Question and Answer STRSAM Start Sampled Address Monitor STRSAMCOL Start SAM Data Collection STRSBS Start Subsystem STRSDA Start SDA STRSEU Start Source Entry Utility STRSPTN Start Support Network STRSRVJOB Start Service Job STRSST Start System Service Tools STRS36 Start S/36 Session STRS36MGR Start S/36 Migration STRS36PRC Start S/36 Procedure STRS38MGR Start S/38 Migration STRTIESSN Start TIE Session STRWP Start Word Processing TFRBCHJOB Transfer Batch Job TFRCTL Transfer Control TFRGRPJOB Transfer to Group Job TFRJOB Transfer Job TFRSECJOB Transfer Secondary Job TRCINT Trace Internal TRCJOB Trace Job UPDDTA Update Data with Temp Program VFYCMN Verify Communications VFYPRT Verify Printer VRYCFG Vary Configuration WAIT Wait WRKACTJOB Work with Active Jobs WRKALR Work with Alerts WRKAUTL Work with Authorization Lists WRKCFGL Work with Configuration Lists WRKCFGSTS Work with Configuration Status WRKCMD Work with Commands WRKCNTINF Work with Contact Information WRKCOSD Work with COS Descriptions WRKCTLD Work with Ctl Descriptions WRKDBFIDD Work with DB Files using IDDU WRKDDMF Work with DDM Files WRKDEVD Work with Device Descriptions WRKDEVTBL Work with Device Tables WRKDIR Work with Directory WRKDOC Work with Documents WRKDOCLIB Work with Remote Document Lib WRKDOCPRTQ Work with Document Print Queue WRKDPCQ Work with DSNX/PC Queues WRKDSTL Work with Distribution Lists WRKDSTQ Work with Distribution Queue WRKDTADCT Work with Data Dictionaries WRKDTADFN Work with Data Definitions WRKF Work with Files WRKFLR Work with Folders WRKHDWPRD Work with Hardware Products WRKJOB Work with Job WRKJOBD Work with Job Descriptions WRKJOBQ Work with Job Queue WRKJRN Work with Journal WRKJRNA Work with Journal Attributes WRKLIB Work with Libraries WRKLIBPDM Work with Libraries Using PDM WRKLIND Work with Line Descriptions WRKMBRPDM Work with Members Using PDM WRKMNU Work with Menus WRKMODD Work with Mode Descriptions WRKMSGD Work with Message Descriptions WRKMSGQ Work with Message Queues WRKNETF Work with Network Files WRKNETJOBE Work with Network Job Entries WRKOBJ Work with Objects WRKOBJLCK Work with Object Locks WRKOBJPDM Work with Objects Using PDM WRKOUTQ Work with Output Queue WRKOUTQD Work with OUTQ Description WRKPGMTBL Work with Program Tables WRKPRB Work with Problem WRKPRDINF Work with Product Information WRKQRY Work With Queries WRKQST Work with Questions WRKSPLF Work with Spooled Files WRKRPYLE Work with Reply List Entries WRKSBMJOB Work with Submitted Jobs WRKSBS Work with Subsystems WRKSBSD Work with Subsystem Desc WRKSBSJOB Work with Subsystem Jobs WRKSOC Work with Sphere of Control WRKSPLF Work with Spooled Files WRKSPLFA Work with Spooled File Attr WRKSYSSTS Work with System Status WRKTIE Work with TIE WRKTXTPRF Work With Text Profiles WRKUSRJOB Work with User Jobs WRKUSRPRF Work with User Profiles WRKUSRTBL Work with User Tables WRKWTR Work with Writers

[hackandlearn]

Glossary of Computer Terms

A20 (Address line 20) The 80286 and higher CPUs allow addresses in real mode to extend slightly beyond the one megabyte mark, which causes an incompatibility with some older programs which expect such addresses to wrap back to the beginning of the address space. For complete compatibility with the 8088, newer machines thus contain circuitry which permits the twenty-first address line (A20) to be disabled. The CPU then effectively has only twenty address lines in real mode, just as the 8088 does, and addresses which would extend beyond the one megabyte mark wrap to the beginning of the address space. See also High Memory Area, Real Mode.

ABIOS (Advanced BIOS) The IBM XT/286 and PS/2 models with 80286 or higher processors contain two separate BIOSes. The ABIOS is a protected-mode BIOS which is used by OS/2. For machines without an ABIOS, such as the IBM AT, OS/2 loads the equivalent of the ABIOS from disk. see also CBIOS

API (Application Program[ming] Interface) The defined set of calls which a program may make to interact with or request services of the operating system or environment under which it is running. Because the inputs and outputs of the calls are well-defined, a program using the API can continue using the identical calls even if the internal organization of the program providing the API changes.

APL (A Programming Language) An interactive, mathematically- oriented language which is well-suited to manipulating matrices. Originally using greek letters and numerous special symbols, thus requiring a special display, versions are now available which use keywords in place of the special symbols.

ASCIZ A NUL-terminated ASCII string. The ASCIZ string "ABC" consists of the four bytes 41h, 42h, 43h, and 00h. Unless otherwise specified, maximum lengths given in the interrupt list do not include the terminating NUL.

AVATAR (Advanced Video Attribute Terminal Assembler and Recreator) A set of control codes which may be used to affect the output of characters to the screen on systems equipped with an appropriate driver. Similar in intent to ANSI sequences, AVATAR has shorter command sequences and provides additional PC-specific functionality. AVATAR is primarily used by the Opus and Maximus bulletin board systems (it was designed by one of the developers of the Opus system).

BASIC (Beginner's All-purpose Symbolic Instruction Code) A programming language originally designed as a means of teaching FORTRAN. There are many variations of BASIC with differing capabilities; the majority are interpreted but compiled BASIC is becoming more popular. All genuine IBM personal computers (including the latest PS/2 models) come equipped with a cassette-based BASIC interpreter in ROM.

BCD (Binary Coded Decimal) A method of data storage where two decimal digits are stored in each byte, one in the upper four bits and the other in the lower four bits. Since only the values 0 through 9 are used in each half of a byte, BCD values can be read as decimal numbers on a hexadecimal display of memory or a file.

Big-Endian One of the two major ways of organizing multi-byte numeric values in memory. A big-endian layout places the most significant byte of the value in the lowest (first) memory location, i.e. 12345678h is stored as 12h 34h 56h 78h. Motorola processors are big-endian. Compare Little-Endian.

BIOS (Basic Input/Output System) A set of standardized calls giving low-level access to the hardware. The BIOS is the lowest software layer above the actual hardware and serves to insulate programs (and operating systems) which use it from the details of accessing the hardware directly.

BIOS Parameter Block The BIOS Parameter Block stores the low-level layout of a drive. See also INT 21h Function 53h.

Boot To start up the computer or operating system. The term "boot" is a contraction of "bootstrap", which in turn comes from the expression "to lift oneself by one's boot straps." The ROM BIOS on IBM PCs and compatibles reads in the first sector of the disk, which contains a short (less than 500 bytes) program that reads in a portion of the operating system, which in turn reads in the remainder of the operating system.

Boot Drive The disk drive from which the operating system was booted. See also Boot.

BPB see BIOS Parameter Block

Breakpoint When debugging, a memory location which when accessed causes a break in the normal flow of execution and the invocation of the debugger. Used to let a program run at full speed until a certain instruction is reached or (less frequently) a particular data item is accessed or changed.

Cache Caching is a method of increasing performance by keeping frequently-used data in a location which is more quickly accessed. The most common caches are disk caches (store disk sectors in RAM) and RAM caches (store portions of main memory in special high-speed RAM which may be accessed as fast as the CPU is capable of accessing memory). See also Delayed Write, Write-Through.

Callback A call to a specified function made by the operating system or operating environment when a request (usually an asynchronous request) completes. This permits the calling program to continue operating while the request is processed yet still be aware of its completion immediately without the need to constantly poll the request's status. See also Callout.

Callout A call made by the operating system, operating environment, or an application program on various events, which may be intercepted by other software which is interested in the current state of the system. See also Callback, External Device Interface.

CAS see Communicating Applications Specification

CBIOS (Compatibility BIOS) The IBM XT/286 and PS/2 models with 80286 or higher processors contain two separate BIOSes. The CBIOS is a real-mode BIOS which is compatible with the earlier products in the IBM PC family and PS/2 models with 8086 processors. See also ABIOS.

CDS see Current Directory Structure

CGA (Color/Graphics Adapter) One of the two video display boards introduced together with the original IBM PC. See also HGC, MDA.

Clock Tick 1/18.2 second, or approximately 55 milliseconds. This is the rate at which the IBM PC's system clock is updated.

CMOS (Complementary Metal-Oxide-Silicon) A type of integrated circuit design known for its low power consumption.

CMOS RAM A small amount (typically 64 or 128 bytes) of memory in the system's real-time clock chip that is preserved by the clock's battery and is used for storing configuration information. See also Real-Time Clock.

Communicating Applications Specification DCA and Intel's standard programmatic interface for sending and receiving FAXes via any of a number of internal FAX boards.

CP/M (Control Program for Microcomputers) An early operating system for micros based on the 8-bit Intel 8080 CPU (and later the compatible 8085 and Zilog Z80 CPUs). MSDOS version 1.0 was essentially a clone of CP/M for the Intel 8086.

CP/M-86 One of the three operating systems offered by IBM for its original PC (the other two were MSDOS and the UCSD p-System). It has since evolved into DR-DOS version 6.

CPU (Central Processing Unit) The microprocessor which executes programs on your computer.

Current Directory Structure The data record used by DOS to keep track of the current directory on a drive; whether the drive is valid, network, SUBSTituted, or JOINed; and other pertinent information. See also INT 21h Function 52h.

Cylinder The set of concentric tracks of data located at the same position on each data-bearing surface of the disk. A double-sided floppy will contain two tracks per cylinder.

DAC (Digital-to-Analog Converter) A hardware device (in its simplest form, nothing more than a set of interconnected resistors) which converts a digital number into an analog signal whose voltage is proportional to the value of the digital number. VGA and later color video boards use DACs to convert color values into the analog signals sent to the display; sound boards normally use DACs as well.

DCC (Display Combination Code) A number which indicates both the type of display adapter board and the type of monitor attached to the video board.

Delayed Write A form of caching in which control is returned before the data is actually written to the storage media. See also Cache, Write-Through.

Device Driver An interface module between the device-independent portions of the operating system and an actual hardware device which converts device-independent requests into the actual sequence of device operations to perform the requested action. IO.SYS contains the standard, built-in MSDOS device drivers such as CON, COM1, AUX, PRN, etc. See also INT 21h Function 52h and INT 2Fh Function 0802h.

Device Driver Request Header The data structure passed to a device driver which contains the command to be executed, its parameters, and space for a returned status and data values. See INT 2Fh Function 0802h.

DGIS (Direct Graphics Interface Standard)

Direct Memory Access A method whereby peripherals may transfer data into or out of main memory without the involvement of the CPU.

Disk Transfer Address The Disk Transfer Address indicates where functions which do not take an explicit data address will read or store data. Although the name implies that only disk accesses use this address, other functions use it as well. See INT 21h Function 4Eh for an example of the DTA's use.

DLL see Dynamic Link Library

DMA see Direct Memory Access

DOS Extender A program which allows a program to run in protected mode while still retaining access to real-mode MSDOS services. See also Protected Mode.

DOS Parameter List The DOS Parameter List is used to pass arguments to SHARE and network functions. See also INT 21h Function 5D00h.

DOS Protected-Mode Interface An API which provides basic services for protected-mode programs to allocate memory, invoke real-mode software, etc. See also Virtual Control Program Interface.

DPB see Drive Paramter Block

DPL see DOS Parameter List

DPMI see DOS Protected-Mode Interface

DRAM (Dynamic Random Access Memory) RAM memory which essentially consists of a tiny capacitor for each bit of memory. Since capacitors do not hold a charge indefinitely, DRAM must be constantly refreshed to avoid losing its contents. Also, the process of reading the contents of the memory are destructive, meaning extra time must be spent restoring the contents of memory addresses which are accessed, so DRAM is slower than SRAM. See also Refresh, SRAM.

Drive Parameter Block The DOS Drive Parameter Block stores the description of the media layout for a logical drive, as well as some housekeeping information. See also INT 21h Function 1Fh and INT 21h Function 32h.

DTA see Disk Transfer Address

DWORD Doubleword; four bytes. Commonly used to hold a 32-bit segment:offset or selector:offset address.

Dynamic Link Library A collection of subroutines which are linked with a program at the time it is loaded into memory rather than permanently placed in the executable. This has the advantage of allowing a single copy of the subroutine library to reside on disk or in memory even when it is used by many programs. It also permits all programs using the DLL to be updated without recompiling simply by installing a new version of the library.

EGA (Enhanced Graphics Adapter) IBM's second color video board for the IBM PC family, capable of a maximum resolution of 640x350 pixels in 16 simultaneous colors of a total of 64 possible colors.

EISA (Enhanced Industry-Standard Architecture) A 32-bit superset of the IBM AT's expansion bus (which is now known as the ISA or Industry-Standard Architecture bus).

EMS see Expanded Memory Specification

EOI (End of Interrupt) A particular command sent to the interrupt controller to indicate that the interrupt has been handled by software and that new interrupts of the same or lower priority may now be signalled by the interrupt controller.

ESDI (Enhanced Small Device Interface) A disk drive interface type which was briefly popular before IDE took over. An ESDI drive can transfer data between the drive and controller at 10, 15, or 20 megabits per second, which is faster than an MFM or RLL controller but slower than what is possible with an IDE or SCSI drive. See also IDE.

Exception A signal by the CPU that some error condition has been encountered that it can not deal with without a program's intervention. The most commonly encountered exceptions on Intel processors are Exceptions 12 and 13, which are stack and general problems, respectively. Exception 13 is typically caused by a memory access which wraps from the end of a segment back to the beginning.

Expanded Memory Specification A specification devised by Lotus, Intel, and Microsoft for accessing more than one megabyte of memory by bank-switching additional memory into the one megabyte real mode address space.

Extended BIOS Data Area A block of memory, typically the 1K at the top of conventional memory, which is used to store additional data for use by the BIOS which does not fit into the 256-byte data area at segment 0040h.

Extended File Control Block A DOS File Control Block which has had an additional seven bytes prepended to permit control of file attributes (which are stored in the appendage).

Extended Memory Memory beyond the one megabyte address which is available only on 80286 and higher machines. Except for a small portion (the High Memory Area), extended memory is only accessible from protected mode.

Extended Memory Specification A specification devised by Microsoft which allows multiple programs to share extended (above 1 megabyte) memory and noncontiguous memory above 640K.

External Device Interface A series of calls made by the DESQview multitasker on various "interesting" events, which may be intercepted by programs which wish to keep track of the current system state.

FAT see File Allocation Table

FCB see File Control Block

File Allocation Table A data structure on disk that records which clusters are free, which are unusable, and which have been allocated. The clusters occupied by a file are linked into a list in the file allocation table, allowing DOS to find the contents of the file.

File Control Block A data record in the calling program's address space which is used by DOS 1.x functions to record the state of an open file.

File Handle A small positive integer used to identify the previously-opened file on which a program wishes to perform an operation.

Flush To force the copying of any data still stored in temporary buffers to its final destination.

FM (Frequency Modulation) A method of encoding data as a series of magnetic flux reversals on disk or tape, commonly known as single-density recording. In frequency modulation, a series of clock pulses are written at regular intervals, with one data bit for each clock pulse. See also MFM, RLL.

Formatting Preparing a storage medium (usually magnetic media such as a disk or tape) for storing data. Low-level or physical formatting writes all necessary housekeeping data to enable the storage device to read the media and may also initialize the storage units on the media to a known state. High-level or logical formatting writes data used by the operating system, such as allocation information and directories onto media which has already been physically formatted. Formatting programs often perform both a low-level and a high-level format.

FOSSIL (Fido/Opus/Seadog Standard Interface Layer) A standardized API for performing serial I/O, originally used by the Fido and Opus bulletin- board software and Seadog bulletin-board mailer, but now in wider use.

FTP (File Transfer Protocol) The standard protocol for copying files from one machine to another on a TCP/IP (Internet) network. Also the program of the same name with which a user may transfer files.

Gather-Write see Scatter/Gather

Handle A short identifier, usually a small integer or a pointer, for some other object which is maintained or controlled by the operating system or environment; a particular handle may be valid system-wide or may have meaning only for a particular process. See also File Handle.

HGC (Hercules Graphics Controller) A monochrome video adapter capable of 720x352 monochrome graphics. The HGC was the first non-IBM video adapter for the IBM PC. See also CGA, MDA.

High Memory Area The first 65520 bytes (64K less 16 bytes) of extended memory. This area is accessible from real mode on the 80286 and higher processors because these processors do not wrap addresses at one megabyte as the 8088 and 8086 do. See also A20, INT 2Fh Functions 4A01h.

HMA see High Memory Area

Horizontal Retrace When a monitor has finished displaying a single scan line, it must move it electron beam(s) back to the left edge of the CRT, during which time it turns off the beam. On the original CGA (and some early clones), the only time one could access the display memory without causing "snow" was during the horizontal or vertical retrace periods, as the display adapter was not itself accessing the display memory during those times. See also Vertical Retrace.

IDE (Integrated Drive Electronics) A type of disk drive interface which essentially extends the PC's expansion bus all the way to the drive and places the drive controller on the disk drive itself. See also ESDI.

IFS see Installable File System

Installable File System An Installable File System which allows non-DOS format media to be used by DOS. In most ways, an IFS is very similar to a networked drive, although an IFS would typically be local rather than remote.

IP (Internet Protocol) The lower level (transport layer) of the TCP/IP protocol suite. IPC (Inter-Process Communication) Any one of numerous methods for allowing two or more separate processes to exchange data.

IPX (Internetwork Packet Exchange) A low-level layer of Novell's NetWare networking software.

IRQ (Interrupt ReQuest) A hardware line connected to the interrupt controller chip which signals that a CPU interrupt should be generated.

ISA (Industry-Standard Architecture) The expansion bus used by the IBM PC/AT. See also EISA.

JFT see Job File Table

Job File Table The Job File Table (also called Open File Table) stored in a program's PSP which translates handles into SFT numbers.

LCD (Liquid Crystal Display)

List of Lists An internal DOS table of lists and other tables through which most DOS-internal data structures may be reached. See INT 21h Function 52h.

Little-Endian One of the two major ways of organizing multi-byte numeric values in memory. A little-endian layout places the least significant byte of the value in the lowest (first) memory location, i.e. 12345678h is stored as 78h 56h 34h 12h. Intel processors are little-endian. Compare Big-Endian.

LPT Abbreviation for Line PrinTer.

MCB see Memory Control Block

MCGA (Multi-Color Graphics Array) The low-end color adapter offered in IBM's early PS/2 series machines.

MDA (Monochrome Display Adapter) A text-only video adapter introduced together with the original IBM PC.

Memory Control Block The data structure containing the length and owner (among other things) of a portion of the memory managed by DOS. See INT 21h Function 52h.

MFM (Modified Frequency Modulation) A method of encoding data as a series of magnetic flux reversals on disk or tape, commonly known as double-density recording. In contrast to FM, modified frequency modulation omits all clock pulses except those between pairs of zero bits.

Mickey The smallest increment of motion a mouse can sense.

MIDI (Musical Instrument Digital Interface) A standardized interface for controlling musical instruments with a computer.

Modem (contraction of MOdulator/DEModulator)

Multitasking Any of a number of methods by which multiple programs may execute concurrently, with rapid switching between the programs giving the appearance that all are executing simultaneously.

MZ The letters M and Z appear in numerous places in DOS (memory control blocks, .EXE header, etc.); the conventional explanation is that these are the initials of Mark Zbikowski, one of the principal architects of MSDOS 2.0.

NCB see Network Control Block

NDIS (Network Driver Interface Specification) A hardware-independent network interface developed by Microsoft and 3com.

NetBIOS One of a number of low-level device-independent network interfaces; the other major interfaces are Novell's IPX and the Internet's IP (Internet Protocol, the lower-level portion of TCP/IP).

Network Control Block A Network Control Block used to pass requests to NetBIOS and receive status information from the NetBIOS handler.

Network Redirector A program which permits access to network devices (disks, printers, etc.) using the MSDOS kernel network redirector interface.

Network Shell A program which permits access to network devices (disks, printers, etc.) by intercepting DOS calls before they reach the DOS kernel and handling those operating on network devices while passing through actions on local devices.

NMI see Non-Maskable Interrupt

Non-Maskable Interrupt An interrupt which can not be disabled by clearing the CPU's interrupt enable flag, unlike most normal interrupts. Non-maskable interrupts are typically used to signal calamities which require immediate action, such as a hardware failure or imminent loss of power.

Non-Volatile RAM Memory which can be modified like normal RAM but does not lose its contents when the system's power is turned off. This memory may be powered by a battery when the system power if off, or it may be a type of memory which does not need electricity to maintain its contents, such as EEPROM or bubble memory.

NVRAM see Non-Volatile RAM

ODI (Open Data-link Interface) A hardware-independent network interface developed by Novell, Inc.

Open File Table see Job File Table

Overscan Area The "border" between the edge of the area where graphics or text can be displayed and the actual edge of the area the video adapter can illuminate on the monitor's screen.

Overscan Register On a display adapter, the control register which specifies the color to be displayed in the overscan area.

Packet Driver Any one of the numerous drivers conforming to FTP Software's Packet Driver Specification, which provides a hardware-independent network interface.

Page Fault A CPU-generated signal, and the operating system's reaction to it, generated when a program accesses a page of virtual memory which is not located in RAM at the time. The operating system's response is to load in the required page, possibly writing some other page out to disk in order to make room.

Palette Register A memory location on the video controller which specifies the actual color displayed for a particular color number.

Park To move a hard disk's read/write heads to a position in which it is safe to turn off the power and transport the disk drive. Many drives also lock the heads into position when they are parked, providing additional protection from sudden movement.

Pel see Pixel

Pixel A picture element, the smallest addressable unit of a graphical display.

Post Make known, either generally or to a specific handler, that a particular event of interest has occurred.

POST see Power-On Self-Test

Power-On Self-Test A brief examination of the system's functionality performed each time the system is turned on.

Print Spooler see SPOOL.

Program Segment Prefix The Program Segment Prefix is a 256-byte data area prepended to a program when it is loaded. It contains the command line that the program was invoked with, and a variety of housekeeping information for DOS.

Protected Mode One of the operating modes of the 80286 and higher Intel processors, in which addresses used by programs no longer correspond to physical addresses and the CPU enforces various protection mechanisms designed to prevent one program from disrupting other programs or the operating system.

PSP see Program Segment Prefix

PWORD Six bytes. Used to hold an 80386 protected-mode "far" address, consisting of a segment selector and a 32-bit offset, or a Turbo Pascal "real" variable.

QWORD (quad-word) Eight bytes.

RAM (Random Access Memory)

Real Mode One of the operating modes of the 80286 and higher Intel processors, and the only operating mode of the 8088, 8086, 80186, and 80188 processors. In this mode, all addresses used by programs correspond directly to real physical addresses (thus the full name, Real Address Mode) and there are no CPU-imposed protections between programs.

Real-Time Clock A battery-powered clock which continues to maintain its time even while the system is powered down. On PCs, the real-time clock contains a small amount of battery-powered memory (set CMOS RAM).

Redirector Interface The set of device-independent INT 2Fh function calls invoked by the MSDOS kernel to operate on devices it recognizes as network devices. These function calls provide a lower-level interface than the INT 21h calls made to DOS, allowing a program intercepting these functions to be simpler than one intercepting INT 21h calls. See INT 2Fh Functions 1100h through 1130h.

Refresh The process of periodically rewriting the contents of a DRAM memory chip to keep it from fading. The term "refresh" is also commonly applied to redrawing the image on a CRT's phosphors.

RGB (Red-Green-Blue) The color specification mechanism normally used in computer displays, where colors are separated into their primary-color components. .

RLL (Run-Length Limited) A method of encoding data as a series of magnetic flux reversals on disk or tape. RLL can achieve higher data densities than MFM recording because it encodes the data such that (on average), fewer than one flux reversal per data bit is required (however, timing becomes more critical). RLL is actually an entire family of encoding methods, specified with two numbers indicating the minimum and maximum distances between one bits (flux transitions). The variant normally called RLL is RLL-2,7; RLL-1,7 and RLL-3,9 are also in use. MFM is in effect RLL-1,3.

ROM (Read-Only Memory) A memory for program storage which may not be changed by the program as it runs.

RTC see Real-Time Clock

Scan Code The actual key number sent by the keyboard, which differs from the key codes seen by application programs. The enhanced (101/102-key) keyboard actually sends different scan codes than the original (83/84-key) IBM keyboard, but these are normally translated by the keyboard controller into the scan codes used by the original keyboard before they become visible to programs.

Scatter/Gather A technique in which the contiguous data of a disk sector or sectors is transferred to or from multiple non-contiguous areas of memory. When reading into multiple areas of memory, this is called a scatter-read; the opposing operation is called gather-write.

Scatter-Read see Scatter/Gather

SCSI (Small Computer Systems Interface) A system-independent expansion bus typically used to connect hard disks, tape drives, and CD-ROMs to a computer. A host adapter connects the SCSI bus to the computer's own bus. .

SDA see Swappable Data Area

Sector The smallest addressable unit of data on a disk; under MS-DOS, this is normally 512 bytes.

SFT see System File Table

SPOOL (Simultaneous Peripheral Operation OnLine) The process of performing output to a slow peripheral such as a printer while other tasks continue running on the CPU. This term dates back to mainframe days before the invention of timesharing.

SQL (Structured Query Language)

SRAM (Static Random Access Memory) RAM which typically consists of one flip-flop per bit of memory. Unlike DRAMs, static RAM retains its contents as long as power is applied. Because there is no need to refresh the contents of memory addresses which are read, SRAM is faster than DRAM, but it is more expensive and typically is available in much smaller sizes than DRAM because each bit occupies more space on the chip.

SVGA (Super VGA) A video adapter capable of higher resolution (pixels and/or colors) than the 320x200x256 and 640x480x16 which IBM's VGA adapter is capable of producing.

Swappable Data Area The portion of the DOS data segment containing all of the variables used internally by DOS to record the state of a function call in progress.

System File Table A System File Table is a DOS-internal data structure used to maintain the state of an open file for the DOS 2+ handle functions, just as an FCB maintains the state for DOS 1.x functions.

TCP (Transmission Control Protocol) A higher level (session layer) of the TCP/IP protocol suite.

TCP/IP The protocol suite originally developed by DARPA for use on its ARPAnet network, which is now known as the Internet.

TSR (Terminate and Stay Resident) A program which remains in memory after terminating in order to provide services to other programs or the user. The name comes from the name of the DOS function call used to remain in memory after termination.

Track One of multiple concentric circular rings of data on a single data-bearing surface of a disk. Tracks at the same location on different surfaces form a cylinder.

UMB see Upper Memory Block

UNC (Universal Naming Convention) The standard way of describing network servers and their directories under MS-DOS and Windows NT. A name in UNC format consists of two backslashes followed by the server name, optionally followed by another backslash and a list of backslash-separated fields; for example \SERVER1\SHARED-DIR\SUBDIR1\SUBDIR2\FILENAME.EXT.

Upper Memory Block A noncontiguous section of allocatable memory located between the 640K and 1024K addresses.

V86 see Virtual-86 Mode

VCPI see Virtual Control Program Interface

VDM see Virtual DOS Machine

VDS see Virtual DMA Specification

VDU (Video Display Unit) Mainframe-speak for computer monitor.

Vertical Retrace When a monitor has finished displaying an image by sweeping its electron beam(s) over the face of the CRT, it has to move the beam back up to the top of the display. During the time this takes, the beam is turned off. The vertical retrace interval is a good time to change the displayed picture for smooth animation.

VESA (Video Electronics Standards Association) An industry group which sets both hardware and software standards and recommendations. The term VESA is also used to denote compliance with the VESA SuperVGA BIOS Extensions, a standard set of video BIOS functions for accessing video modes of higher resolution than those defined by IBM.

VGA (Video Graphics Array) The video adapter introduced with the IBM PS/2 series of computers.

Virtual-86 Mode One of the operating modes of the 80386 and 80486 processors in which user programs run as if the CPU were in Real Mode, while providing the protection and address-mapping capabilities of Protected Mode to a supervisor program which oversees the virtual machine on which the user programs are running. This mode is called Virtual-86 because one or more virtual 8086 environments are run on a single CPU.

Virtual Control Program Interface A simple API for protected-mode programs to allocate memory and switch into or out of protected mode.

Virtual DMA Specification A set of interrupt calls which permit the use of DMA even on systems running in protected or Virtual-86 mode with their address remapping, or systems such as Micro Channel PS/2s with multiple bus masters independently performing DMA operations.

Virtual DOS Machine A special type of virtual machine provided by OS/2 version 2.0, in which a copy of MS-DOS or an MS-DOS compatible operating system (or even an incompatible 8086 operating system) is run and appears to have full control of the system.

Virtual Machine One method for multitasking programs is to virtualize the CPU and other hardware, giving the appearance of sole possession of the system to each program being run. Such a virtualized environment is called a virtual machine.

virus A program which attaches itself to other programs for the purpose of duplicating itself. Viruses often (but not always) contain harmful code which is triggered by some event, after a certain number of reproductions, or on a specific date.

VM see Virtual Machine

VxD A virtual device driver for Windows 3.0 or 3.1. S

WORM (Write Once, Read Many) A storage medium which may be written exactly once, but may not be altered once data is stored.

worm A program which duplicates itself, typically across networks. In contrast to a virus, a worm does not attach itself to other programs, but can reproduce itself independently.

[hackandlearn]

The Development Of DOS

THE DEVELOPMENT OF DOS Personal computers began appearing in the mid 1970's, initially as hobbyist toys that didn't even have keyboards or screens.  The first real one, named Altair by a magazine editor's 12-year old daughter who liked a Star Trek episode that took place in that solar system, was built around a jazzed-up calculator chip, the Intel 8080. Produced as a do-it-yourself kit by a company called MITS, it came with 256 bytes of memory. Since it lacked a keyboard, you entered data by flipping switches on the front panel in binary sequence.  Because it had no screen, you had to decode the patterns of blinking lights it produced.  And it didn't let you store data permanently. Two teenagers, Bill Gates and Paul Allen, who had started a company called Traf-o-Data to make Intel-based computers to measure how many cars ran across a rubber hose stretched across the road, saw a picture of the Altos on the cover of an electronics magazine and developed a version of BASIC for it.  Gates upgraded AltairBasic later to include primitive file and disk-storage abilities. The pair changed the comapny name to Microsoft; by 1976 the industry had progressed to the point where Gates was railing against software pirates (although back then pirates were making copies of punched paper tape rather than floppies).  A few years later Gates became the worlds youngest billionaire. Soon after the Altair introduction, some hard-driving salespeople became the market leaders with their Imsai 8080, another Intel-based machine, and the first computer aimed squarely at small businesses.  To let users store data efficiently, Imsai developed a floppy disk drive whose motors and circuits were run by a program called CP/M (Control Program for Microcomputers), which had been licensed from Intergalactic Digital Research - later shortened to Digital Research.  DR's Gary Kildall had created CP/M while working for Intel, to scale down the PL/1 programming language into a version that would fit on a microcomputer.  Intel hadn't seen much value in this brand new CP/M thingy and had given Kildall all rights to it. The early versions of DOS owe quite a bit to CP/M.  In fact, things like the .COM formats of CP/M and DOS and the basic system calls were so similar that programmers could easily switch up from CP/M.  CP/M uses a command interpreter called CCP (or Console Command Processor) and two fundamental system files called BDOS and BIOS to handle files and I/O. This arrangement is nearly identical to the DOS COMMAND.COM, IBMDOS.COM and IBMBIO.COM system trio.  What was especially remarkable about CP/M was that it took up only 4k of space.  DOS 1.0 doubled that and it has been mushrooming ever since. Chain store magnate and leathercrafter Charles Tandy tried unsuccessfully to buy computers from Imsai, then ended up creating his own system, the TRS-80, which contained a Zilog Z-80 chip, 4096 bytes of memory, and came fully assembled rather than in a kit.  To shave a few dollars off the price he designed it to work entirely in upper case letters.  Customers snapped them up as fast as Tandy could make them. What really kicked the microcomputer business into high gear, however, were a handful of visionary renegades from California and Florida. In 1976 Steve Wozniak and Steve Jobs, whose early careers included a stint peddling "black box" devices to circumvent telephone toll billing computers, bought some 6502 chips and built a few hundred copies of a computer they christened the Apple I.  It too worked only in upper case letters.  Their second-generation Apple II offered an optional floppy disk drive, and sold several orders of magnitude more.  On reason for its success was a revolutionary program called Visicalc.  Visicalc turned Apple's little computer into a powerful financial analysis and planning machine. But not all operating systems run on all chips.  CP/M worked on the 8080 and Z80 chips but not on Apples 6502. Microsoft's Gates and Allen moved to Seattle to write programming languages for computers built around Intel and Zilog processor chips and running CP/M. Dismayed that their languages woudln't work on Apples, they considered translating them all to run on Apples proprietary operating system, an arduous job.  Instead they joined the crowd, licensed CP/M, and sold it along with an add-in board that had a Zilog chip on it.  Apple owners could stick the Microsoft boards in their computers and run any CP/M program. But Apple was an 8-bit machine and Gates and Allen felt Intel's new 16-bit processors were the wave of the future.  So did a local board maker called Tim Patterson who worked for Seattle Computer Products. All earlier processor chips managed data in 8-bit chunks.  Intel's new 8086/8088 chips finally doubled the processor power. Patterson's board had an 8086, and he needed a new 16-bit operating system to take advantage of it.  Digital Reserach had announced that it was going to tweak CP/M into a 16-bit version, but Patterson couldn't wait.  In early 1980 he started work on one of his own design called QDOS (Quick & Dirty Operating System) that was to become 86-DOS (or SCP-DOS) and eventually just plain DOS. To make it relatively easy for programmers to translate CP/M softwrae to his system, he retained fundamental CP/M file management structures and mimicked the way it loaded and ran programs.  Patterson then added a device known as a File Allocation Table (FAT) which Gates had used in Altair disk BASIC, and a few other refinements. -------------------------------------------------------------------- DOS 1.0 In late 1980, IBM approached Microsoft and revealed that it was considering production of its own 8-bit computer.  Vast helpings of money, ego, pride and general corporate paranoia have tempered details of this exchange, but the popular version is that IBM wanted Microsoft to design a version of BASIC for its new machine that would be delivered on a ROM chip inside the IBM chassis. Gates was happy to oblige and wanted to do a whole raft of languages, as the story goes, but argued that IBM should consider a 16-bit computer instead. When IBM asked who made a 16-bit operating system, Gates is said to have suggested that IBM contact Gary Kildall - and supposedly even dialled the phone to Digital Research himself. Here the tale gets very fuzzy.  According to the one telling it, when IBM trooped down to see Digital Research the next day, Kildall's wife and lawyer were hesitant to sign IBM's strict non-disclosure agreements. Other stories had Kildall out flying his plane while IBM executives waited impatiently for him to land.  Microsoft's own publications admits that Gates and Allen had heard rumours that Kildall was about to buy a version of BASIC from one of Microsoft's competitors and give it away free with every copy of CP/M-86, which didn't exactly endear him to them. In any event, Gates and Allen bought the rights to Patterson's 86-DOS for around $50,000.00 and proposed to IBM that Microsoft provide BASIC, FORTRAN, Pascal, COBOL, an 8086 Assembler, and the 86-DOS operating system for the new computer.  IBM agreed in November 1980, and on August 12, 1981 introduced the world to its new PC and its main operating system, Microsoft's DOS 1.0, which IBM called PC-DOS.  At the announcement, IBM announced that users would someday be able to buy two competing operating systems: CP/M-86 or the UCSD-p System. But IBM priced these much higher than DOS, and since they were late reaching the market and received little support from other software vendors, they went nowhere. Computer hardware isn't useful without software. And IBM initially didn't offer much software - EasyWriter, a bug-filled version of a mediocre word processor; Adventure, a mainframe text game adapted to run on microcomputers, a DOS version of VisiCalc, some artless business software, a few Microsoft languages and one or two other packages. The most powerful and popular programs back then - dBase II and WordStar - ran only on CP/M systems.  One of IBM's highest priorities was to make it easy for software vendors to translate programs from CP/M to DOS, and it was smart enough to know that making it easy meant making the two operating systems similar. Many of the DOS features that todays users truly hate - such as overly brief eight-character filenames with three letter extensions, terse prompts like A>, and unfriendly or missing messages (such as the stony silence in response to file deletions) were directly swiped from CP/M. So were underlying structures such as File Control Blocks (FCB's), Program Segment Prefixes, and reliance on CP/M's memory loading addresses. DOS did change a few CP/M quirks.  File lengths that were rounded off in CP/M were reported precisely in DOS.  Some commands were turned around to be more logical.  Programmers could treat I/O to peripheral devices like printers and screens the same way that they handled files.  DOS's variable record lengths made disk storage and retrieval far more efficient.  DOS could load and run larger .EXE format files in addition to the smaller CP/M-standard COM-format files which were limited to 64k. And it could keep a program loaded but inactive in memory, so that users could pop it onto their screens whenever they needed it .  DOS relied on a FAT, first used by Bill Gates and Tom Patterson, to keep track of where all the various pieces of a file were stored, and could read and write more than one piece of data at a time, which speeded up disk activity significantly. DOS at least theoretically made it easier for programmers to create their own version of the COMMAND.COM user interface, although none has ever caught on. But the ability to run scripts of commands called batch files became very popular. When DOS reported inevitable errors, it did so in a slightly friendlier way than CP/M, and it handled severe hardware errors far better. DOS also sniffed out new disks automatically while CP/M forced users to log such changes manually, and it kept track of the date files were created or changed. It also split the COMMAND.COM interface into several parts, a mixed blessing. When the PC was new, and IBM offered it with a maximum of 64k memory, this feature was welcome since it let other space-hungry software temporarily steal a few thousand characters of memory from DOS. When the user was finished with the software he'd have to insert his DOS disk in drive A: so that the part of DOS that hadn't been stolen could reload the part that had.  Trouble was that a short time later users were buying systems with ten times that much memory, and the amount of space freed up by this technique was relatively insignificant. But floppy disk users still had to contend with keeping a DOS disk handy to reload the "transient" stolen part. One of the worst things about the first IBM PC and its operating system was that it could store only 160k of data on floppy disks that were clearly capable of storing twice as much.  A standard floppy has two usable sides, but the first PC - and DOS - could only use one. The initial DOS release contained several nasty bugs.  In mid-1982, IBM began shipping PC's with double-sided drives, and released DOS version 1.1 to handle the new storage abilities and to fix several of the early bugs.  Microsoft then released its own generic upgrade which it called MS-DOS 1.25. The initial release of DOS was tiny and relatively crude.  Version 1.0 TIME and DATE commands were separate short programs rather than part of the main COMMAND.COM interface.  While the DOS 1.0 directory listing noted the date a file was changed or created, it ignored the time.  The MODE command couldn't set communications speeds or protocols, or let the PC's parallel printer adaptor work with the many serial printers on the market.  The COPY command wouldn't join or concatenate several small files into a larger one.  The onscreen messages and prompts were especially ugly and cryptic. DOS 1.1 fixed all these problems, or at least made them less irritating. The biggest problem of all was that DOS was still constrained by its CP/M heritage and its clanky internal structure.  And although IBM doubled the amount of disk storage space from 160k to 320k, users found this was far from enough.  They demanded disks that were faster and more efficient. ---------------------------------------------------------------------- DOS 2.0 In March 1983, IBM announced its PC-XT, a beefed-up version of the standard PC that came with three addtional internal expansion slots (for a total of eight), a ten-megabyte hard disk, and a new version of DOS - 2.0. The new hard disk - which IBM referred to as a fixed disk - could hold the equivalent of more than 31 double-sided floppies.  But all that storage space introduced a new problem.  DOS 1.0 and 1.1 had crammed all the file information for each floppy disk into a single directory.  A single-sided floppy had room for a maximum of 64 directory entries, and you could fit only 112 on a double-sided diskette. Keeping track of all the files on a hard disk meant coming up with a new DOS file management and directory system.  CP/M had dealt with large disks by splitting them (or partitioning) them evenly into smaller ones, an inelegant and inefficient solution.  But UNIX, an operating system developed by the phone company, could handle vast volumes of files with relative style and ease. Microsoft had licensed UNIX, and was offering a version of it called XENIX.  At the heart of UNIX/XENIX was a hierarchical or tree-structured directory system that gave users lots of flexibility in dividing up the available storage space. Microsoft adapted this tree-structured system as the core of a significant new incarnation of DOS - version 2.0.  But it blundered slightly.  UNIX used a slash (/) to identify the subdirectory levels that acted as branches on the tree structure.  But earlier DOS versions used slashes as switches (command suffixes such as the /s in FORMAT /s) that turned optional features on and off. Microsoft substituted a backslash (\) to identify subdirectory levels, which eneded up confusing a whole generation of DOS and UNIX users, and caused much consternation abroad where foreign keyboards often didn't come with backslash characters. IBM and Microsoft also had to find a way to deal with an explosion in the number and type of devices that manufacturers were stamping out for the PC. One of DOS's main roles was to manage the communication between the PC and anything else you could hook up to it.  If DOS had to contain explicit internal tables and instructions for every possible device it would end up being absurdly large and cumbersome. Microsoft designed a new version of DOS with hooks in it so that manufacturers of peripheral equipment could supply installable device driver programs to hook the new hardware effortlessly into the operating system.  Users could load these specific additional sets of instructions into DOS as needed, through a special CONFIG.SYS file.  This file also let users customise their systems by telling DOS how much memory it should devote to disk buffers, how many files could be opened simultaneously, and how frequently DOS should check to see whether a user was hitting the Ctrl-Break panic button.  It also made it easy for users to load a replacement command processor if they weren't planning on using the standard COMMAND.COM, or tell DOS if they were storing COMMAND.COM in an unusual place.  And it gave users extended screen and keyboard control with ANSI.SYS, a special device driver supplied by Microsoft in an unsuccessful attempt to standardise certain parts of the user interface across different computer systems. Version 2.0 introduced several new commands most users can't live without.  Its hard to believe, but versions 1.0 and 1.1 didn't have any way to clear the screen.  CLS now does it.  This version was also the first to offer batch file commands such as ECHO, IF, FOR, SHIFT and GOTO. DOS 2.0 also introduced a raft of commands and utilities to give users cintrol of hard disks although some, like the pathetic TREE command - designed to "display the entire directory structure" are a bad joke. Perhaps to compensate, IBM threw in a gem that has become a power users best friend - the mini-assembler in DEBUG.  You can become an absolute computer whiz without ever having to learn a single thing about hex codes or assembly language.  But if you want to climb inside your system and stomp on the gas pedal, there's no better way.  Its a lot easier than you think. One of the most significant changes in DOS 2.0 was the way it dealt with files internally.  To remain compatible with CP/M, DOS 1.0 and 1.1 kept track of critical file information with a device called a File Control Block (FCB).  But as programs became more sophisticated they were forced to manipulate the data stored in FCB's directly, which was awkward and potentially dangerous.  And FCB's had no provision for subdirectory names. DOS 2.0 introduced file handles as an optional way to streamline disk management.  Once DOS knew about a particular file in a partcular directory, it could act on that file simply by using a two-character shorthand code called a handle.  In addition, DOS established five special handles that made it a snap to switch inputs and outputs. Normally the keyboard and screen (which DOS collectively refers to as CON:) act as both the input and output.  But DOS 2.0 let users "redirect" input or output to or from printers, files or other devices. And it allowed users to "pipe" streams of data through filters to do things like turn uppercase files into lowercase, strip out extraneous characters, or sort records into alphabetical order. The sample filters DOS 2.0 provided are actually pretty useful.  They'll let you slog through files and skim out the text you want saved or discarded. They'll sort your directories (or any list of names, numbers, or items that have carriage returns at the end of each entry) lightning fast.  And they'll paue your displays for you so you'll never again have text scrolling off your screen too quickly to read. To top it off, DOS 2.0 provided rundimentary background processing.  DOS was originally designed as a sigle-tasking operating system that let users do just one thing at a time.  But the designers of version 2.0 threw in a PRINT spooler command that could print out one file while a user was actively working on another. While spoolers are nothing new, this one was.  Spoolers normally lop off a big chunk of RAM and trick DOS into sending files to memory that were really destined for the printer.  Then they wait for a quiet moment and re-route the files onto your printed page.  When they're done printing, however, they still hold on to all the memory they've hogged - very inefficient.  The DOS PRINT command reads files off your disks and uses your precious memory much more sparingly.  It watches how you work, and about 18 times each second, if you're not doing something at that precise moment, it sneaks a few characters at a time to the printer. Your computer is so fast that this "time slicing" technique makes it appear that it's doing two things at once, when it really alternating so quickly you don't notice it.  And the best part is that if you happen to be working on something that tales more of your computer's constant attention than usual, you can adjust how frequently the spooler tries to intercede. In addition, DOS increased the number of 512-byte sectors from eight to nine. While DOS kept the number of tracks at 40, this upped the storage capacity of each disk from 320k to 360k.  DOS 2.0 also let users add electronic volume labels to their disks, gave them access to part of the memory called the environment, in which critical system settings were maintained, made memory allocation more efficient, and threw in more than two dozen new commands. With so many changes and features, you'd think a brand new version of DOS would be filled with insidious bugs.  And you'd be right.  In March 1984, a year after the PC-XT introduction, IBM released DOS 2.1 to excise these software errors - and to handle a hardware error it produced called the PC-Jr. The less said about the PC-Jr the better.  While it provided more colours onscreen in graphics mode than IBM's real microcomputers, and came with three-voice sound that could play chords, it was utterly non-standard inside and out.  In fact, it used such a cheap, flimsy disk drive that DOS 2.1 had to slow down the drive performance so the thing wouldn't crash. What's especially sad about all this is that lots of users still rely on DOS 2.1, which means they have to put up with unacceptably slow disk access times even though the're using machines that could handle much higher speeds.  A pity, and another good reason to upgrade to a more recent DOS version. Microsoft ended up producing versions 2.05, 2.11, 2.2 and 2.25 with an added modicum of international time, date, keyboard and currency support.  These may come in handy if you need to work with Korean Hangeul or Japanese Kanji characters; today Microsoft sells DOS in more than 60 assorted languages. ----------------------------------------------------------------------- DOS 3.0 and Beyond IBM's PC and PC-XT brought microcomputing into the mainstream of American business. But these machines were both relatively slow and small. In fact, they weren't really even true 16-bit computers. While an Intell 8088 CPU ticked away inside each one, their system bus - the connecting pathway of wires that ties the CPU to all other parts of the system - was a bottleneck that worked in eight-bit chunks only. IBM introduced its first genuine 16-bit system, the PC-AT. Compared to IBM's earlier releases, this was a real rocketship of a computer. Inside was an 80286 CPU with a trick up its sleeve - it could run everything IBM and Microsoft could throw at it and it could also accomodate Microsoft's ne operating system, OS/2. And it needed a new version of DOS - 3.0. Engineers measure computer performance in many ways. Two prime indicators are the clock speed of the CPU and the average access time of the hard disk. The faster the clock, the faster a computer processes instrauctions and the faster just about everything runs. The speedier the hard disk access time, the sppedier it can read and write programs and data. The higher the clock speed and the lower the average access time, the faster the system. Both the PC and the PC-XT run at 4.77 MHz. IBM sold many different brands of hard disks for the XT, and the average access time was somewhere between 80 and 115 milliseconds. The official clock speed of IBM's first AT was 6MHz, but users quickly found out that by replacing a socketed $4 quartz crystal on the main system board they could boost performance to 8 or even 9 MHz without any ill effects. (IBM is famous for publishing ultraconservative specifications and holding down performance a bit on purpose.) When IBM discovered that users were hot-rodding their systems, they wrote a program that acted as a speed governor and put it on a system ROM chip to stop tampering. All of IBM's AT hard disks ran at 40ms or better. Unfortunately, the first big batch of AT's came with CMI-brand drives that crashed in shockingly high numbers. Hard disks - rapidly spinning precision-crafted aluminium platters with magnetic coatings on both sides - need precise feedback on where their magnetic read/write heads are located. If the location mechanism is off by even a tiny bit the heads can write bad data over good or wipe out important tables that tell the computer where files are stored. Hard disk heads actually "fly" on a cushion of air directly above the surface of the platters themselves. All decent hard disks retract or 'park" the magnetic heads when the power goes off so they don't sink down and plough furrows into your data. To save money, CMI disks used what many believe was an unreliable implementation of "wedge servo" technology. Most other hard disks used a dedicated positioning surface, a whole side of a hard disk platter contained no data and instead acted as a map to those that did. But not CMI's AT drives. And these drives didn't park the heads when you turned the power off. The heads just dropped down onto the data and scarped against it. IBM never really admitted doing anything wrong, but tens of thousands of users know different. If this black episode in computing history had a silver lining, it was that it taught hard disk users how absolutley imperative it is to make frequent and comprehensive backup copies of their work. In any event, a PC-AT running at 8MHz was 67 percent faster than a standard PC or PC-XT. The PC-AT hard disk was twice as fast as the speediest XT disk drive, which made everything seem a lot more energetic, and ended up turbocharging disk-intensive applications such as database searches. On top of all that, the PC-AT could deal with memory in 16-bit chunks, while the PC and PC-XT had to lumber along with half that amount. Clone makers soon started producing respectable AT imitations that chugged along even faster. To avoid falling behind the competition too much, IBM eventually had to nudge the performance upward slightly each time it refined the AT design. IBM's newest PS/2 line of hardware and many high-performance clones on the market make even the fastest AT look like its standing still. With CPU sppeds of up to 25MHz, hard disk access times in the high teens, and a 32-bit bus that moves data four times as efficiently as the one in the original PC, these hot new micros give refrigerator-sized minicomputers a good run for their money. The PC-AT was originally delivered with a 20-megabyte hard disk, although subsequent versions have enhanced both the speed and capacity of its hard disk. Still, 20Mb storage meant that backin it all up would take 56 standard 360k floppies. The mind reels. Apparently, so did IBM's. It dropped a quad-density floppy disk drive, with 1.2Mb capacity into each AT. IBM refers to these as high-capacity drives. Unhappy users have called them something else, unprintable here. The PC-AT's new DOS, version 3.0, could handle the increased floppy disk storage. But it also had to understand every other floppy format. In the space of six years IBM had introduced single-sided and double-sided drives, with eight or nine sectors, and in double or quad density, so downward compatibility meant having to deal with:         * 160k single-sided 5.25"         * 180k    "         "         * 320k double-sided "         * 360k    "         "         * 1.2M    "         " Well, there's compatibility and there's compatibility. Out of the 25 different possible combinations of using the DISKCOPY command to move information from one to the other, 16 won't work. What's more, IBM's PS/2 hardware uses 3.5" diskettes, a whole new ball game. These smaller diskettes are sturdier, easier to transport, and vastly more efficient at storing information. IBM characteristically complicated matters by producing two different and slightly incompatible 3.5" disk formats, one that holds 720k and one capable of storing 1.44Mb of data.  The 5.25" 320/360k format won't go away very quickly, since so many vendors have made it the standard for program distribution.  But the PC-AT's 1.2Mb drive and the low-end PS/2 720k diskette are orphans.         * note: This is US. 720k was very popular in NZ. All IBM microcomputers gave users a clock and calendar that could stamp DOS directory listings with the time and date files were created or most recently updated.  But users had to set the clock each time they started their systems, unless they had purchased an add-in board with a battery-driven clock on it (and most did).  The PC-AT came with its own internal battery run clock/calendar, but it wasn't until DOS 3.3 taht users could reset it easily. Program developers live by a rule: "The software is never finished." Each release of DOS or any commercial application is quickly followed by a version with bug fixes, sppedups, and forgotten utilities.  Market considerations force manufacturers to ship everything at the earliest possible date.  Microsoft officially admits that DOS 3.0 "wasn't quite ready" at the introduction of the PC-AT.  But it went out the door anyway. Today, virtually every desk in America has a telephone in one corner. IBM's vision of the future puts a computer terminal next to it, and strings all the terminals together electronically.  Networking computers this way has lots of advantages.  It lets users "mail" messages and files to each other, and share centralised databases of information. Networks can also let users share expensive peripherals like plotters or laser printers, but it doesn't make much sense installing three $1500 network hookups to share one $1500 laser printer. Today networks are interesting to a minority of users only - although the number grows as the costs and headaches associated with using them are reduced. Networks introduce their own special set of problems.  Two users may reach for the same database records at the same time, and something has to mediate the conflict.  Worse, giving users access to centralised information means someone has to decide who gets access to what.  And then something has to keep track of the authorisation levels and enforce it all, and make sure the right data is routed to the right place. Microsoft designed DOS version 3.0 to support the official IBM PC network hardware.  Unfortunately, the AT was ready before the network features of DOS were, and the Microsoft designers had to deactivate these features in the final product.  They finally turned them back on again in version 3.1, released in November 1984.  But DOS 3.1 was picky; it would handle only certain well-behaved networks. DOS 3.0 introduced a streamlined method for integrating FCB's and handles. And while it provided a small handful of new features, none was a radical departure from DOS 2.1. In fact, IBM stated in its documentation that "DOS 3.0 does not replace DOS 2.1". But it did fix a nasty 2.1 oversight, by making it harder for users to format their hard disks if they weren't careful. (It wasn't until version 2.0 that DOS even asked for confirmation if users tried to delete all the files on their disk with a single ERASE *.* command.) Version 3.0 also let users make files read-only to prevent any inadvertent changes or deletions. Version 3.1 provided better "aliasing" features to combine drives and directories and to trick DOS into treating a subdirectory like a disk drive. DOS 3.2 introduced users to 3.5" diskettes (although the tools it provided to do this were downright awful), made it easier for them to upgrade DOS versions, and gave them one of the best but least-used new commands, XCOPY. DOS 3.3, tossed off by IBM pitchment at the introduction of the PS/2 as an "interim solution" and the operating system for a string of dogs including the PC Convertible, Portable PC, and PC-Jr, deftly excised a heap of user headaches, and added a few sizzling new tricks. As all seasoned hard disk users are aware, working efficiently on a hard disk machine means pigeonholing related programs and data in electronic file drawers called subdirectories. But users who are currently working in one subdirectory often want to execute a program or look at data stored in another. Since version 2.0, users had been able to tell the PATH command to check specified subdirectories for executable files (with filenames ending in COM, EXE or BAT). This let users run programs in other subdirectories, but it didn't let them get at distant data. Nonexecutable files remained immune to even the most comprehensive search, forcing power users to purchase commercial "path extender" programs, or struggle with the DOS 3.1 SUBST command.  The DOS 3.3 APPEND command made this process relatively easy - and a lot cleaner. Serial ports are your system's main gateway to the world.  Version 3.3 let MODE cruise along with four serial ports rather than two (OS/2 can use 8) and cruise along at 19200 baud, double the previous limit.  And IBM finally recognised that at least twice a year users need to reset their internal IBM clocks and provided a way of doing this without hunting down their Diagnostics disks, figure out which option adjusts the time, and grind through all the irritating preliminary screens.  The 3.3 TIME and DATE commands automatically adjusted IBM CMOS memory to reflect the change. Another improvement was the newfound ability of the DOS 3.3 ATTRIB command to gang-process all files within a directory and its related subdirectories, which made it easier to create backups and prevent inadvertent file deletions or changes.  Unfortunately, the same process used by ATTRIB can also hide files from casual snooping, but IBM's manual won't show you how. The original DOS architects preferred working with 512-byte disk sectors, and used a FAT to keep track of what data was in which sector. When they designed the FAT they used 16-bit addresses, which allowed a maximum of 65,536 (64k) table entries.  This clamped a firm 32Mb limit on the size of any physical hard disk (512 x 65,536 = 33,554,432 bytes). To get around this limit, manufacturers either had to increase the sector size, which made their hardware non-standard and relatively wasteful, or come up with an entirely new file management scheme, which ended up being even more non-standard. IBM tuned DOS 3.3 to divide physical hard disks into smaller "logical" drives, and fixed the FDISK command to create extended DOS partitions in addition to the primary ones they were able to carve out previously. Each extended partition could be further subdivided into logical drives 32Mb or smaller, with their own drive letters.  Compaq quickly made it even easier to use enormous hard disks, by introducing DOS 3.31 that boasted 32-bit FAT addresses. To expedite directory searches with the new generation of larger hard disks, DOS 3.3 provided a filename cache utility called FASTOPEN. Caches keep track of things in memory rather than on disk, which speeds many processes up significantly.  FASTOPEN notes the location of files and subdirectories (which are really just special classes of files) the first time you hunt for them, and then directs DOS to the exact spot on the disk the next time you have to deal with them. The DOS BACKUP command had always been so pathetic that an entire industry of third-party backup software has evolved to fill the gap. While the version 3.3 enhancements aren't going to put those developers out of business, they will bring some users back into the fold.  Under previous DOS versions you had to format a tall stack of disks before strating the backup process.  If you ran out of formatted disks halfway through you had to abort and either find a way to catch up, or start the whole elaborate, time-consuming procedure all over again. In DOS 3.3 the BACKUP command can summon the FORMAT command and prepare unformatted disks if necessary - with certain irritating restrictions. And you have to limit the disks and drives you use; it still can't mix and match.  The DOS 3.3 BACKUP works faster and more efficiently than older versions, by copying all smaller files into a single enormous one, and by creating a guide file that tells DOS how to take the big file apart and restore it properly again later.  It also creates a log file telling you what it did where. The DOS 3.3 RESTORE gives you added flexibility in restoring backed-up files by date and time, as well as those deleted or changed since you last backed up, or files that are no longer on the target disk.  Better yet, while older versions of RESTORE let you accidentally obliterate your system files (IBMBIO.COM, IBMDOS.COM and COMMAND.COM or their MS-DOS counterparts) with older backed-up versions, DOS 3.3 RESTORE won't.  Inadvertently mixing versions of hard disk system files is like replacing a heart surgeon in the middle of an operation, with a tree surgeon. Batch files can take the anguish out of tricky or repetitive tasks.  The first thing most power users do when they create a batch file is turn off the display by issuing an ECHO OFF command.  This stops DOS from littering your screen with the frantic prompts, messages, and other electronic graffiti a batch file generates.  But users had no authorised way of preventing this ECHO OFF command from adding to the screen clutter itself.  Version 3.3 users can prevent such clutter simply by prefacing any command with an @ symbol. in addition, DOS 3.3 could CALL one batch file from within another, execute it, and then return to the original batch file and continue executing it.  Doing this kind of "nesting" under previous versions of DOS meant that each batch file had to load its own separate version of COMMAND.COM to do its work, exit, and drop back to yet another version - which was sort of like restarting a movie every time a latecomer walked into the theatre.  DOS 3.3 also documented environment variables for the first time, which let users pass information back and forth from application to application. DOS 3.0 to 3.2 came in five international flavours. By executing the appropriate KEYBxx command, users could transform the keyboard into British, German, French, Italian or Spanish modes.  With version 3.3, IBM totally revamped the way DOS handled foreign alphabets.  IBM's manuals have gotten a bit better over the years, but the three abtruse and seemingly contradictory chunks on this international support virtually defy comprehension.  IBM prefaced its long appendix-like treatment of the topic with the caveat "You can use code page switching without fully understanding everything about it." After poring over the text, you'll know why this was included.  And if you live in the United States, you'll take one look, put your hand over your heart, and say, "Thank God we're Americans." For the first time, DOS 3.3 set a default number of disk buffers based on your system's configuration.  Under previous versions, it assumed evert PC and XT user really wanted only two and every AT user only three.  DOS will now sniff out what hardware you have available, and allocate from two buffers (minimal RAM, no hi-density floppies, 3.5" diskettes, or hard disks) to 15 (and machine with more than 512k of RAM).  If you're using a big hard disk, you may want more than 15. Better yet, try a commercial file cache program. The Future IBM and Microsoft continue to add and adapt messages and prompts; the infamous and ubiquitous DOS error message "Abort, Retry, Ignore?" became a more chilling "Abort, Retry, Ignore, Fail?" under DOS 3.3.  This isn't exactly friedly.  When Microsoft originally designed DOS it published all the specifications so that other manufacturers could replace the COMMAND.COM user interface with something different, such as a visual shell.  Several amateurs have tried, but nothing has come of it. Microsoft itself tried an easier interface called WINDOWS, but users have resisted, calling the interface overly large, ungainly, and slow. Microsoft and IBM have adapted Windows as a graphic front-end called Presentation Manager for OS/2. DOS needs all sorts of help; way back when the EGA was first introduced, for instance, users complained that the MODE command couldn't deal with any of the new graphics settings, such as 43 or 50 lines of text, or the far better colour selection.  Now that VGA is becoming the norm, DOS still doesn't directly handle anything better than CGA. (PC-DOS 4.0 and 4.01 have been released since this was written; MODE now supports high resolution text displays and multiple serial ports. However few users have switched to 4.0 or 4.01 in New Zealand, particularly after the OS was slammed by the foreign press as being full of bugs, inconsistent in its user interface, and a memory hog.  Some Wellington BBS users have successfully changed to DOS 4.01, and have experienced no real problems in their non-demanding environment.  Most users with only 640k will probably prefer to stick with DOS 3.2 or 3.3, and those with large disks to 3.31.) [And since *that* was written, most new computers are sold with a 40MB disk minimum and DOS 4.01. The product is now quite stable. DOS 5.0's release is imminent.] ----------------------------------------------------------------------