PCjs Machines

IBM PC DOS 1.00

PC DOS 1.00 was completed in August 1981 and announced at an IBM press conference on August 12, 1981, when IBM introduced the original IBM PC (Model 5150). It was released on one single-sided (160Kb) diskette, and included 23 BASIC Programs.

Directory Listing, Documentation, and Feature Summary are provided below. You can also dig into the PC DOS 1.00 Boot Sector using the PCjs Debugger.

Directory of PC DOS 1.00

 Volume in drive A has no label
 Directory of A:\

IBMBIO   COM*     1920   7-23-81  12:00a
IBMDOS   COM*     6400   8-13-81  12:00a
COMMAND  COM      3231   8-04-81  12:00a
FORMAT   COM      2560   8-04-81  12:00a
CHKDSK   COM      1395   8-04-81  12:00a
SYS      COM       896   8-04-81  12:00a
DISKCOPY COM      1216   8-04-81  12:00a
DISKCOMP COM      1124   8-04-81  12:00a
COMP     COM      1620   8-04-81  12:00a
DATE     COM       252   8-04-81  12:00a
TIME     COM       250   8-04-81  12:00a
MODE     COM       860   8-04-81  12:00a
EDLIN    COM      2392   8-04-81  12:00a
DEBUG    COM      6049   8-04-81  12:00a
LINK     EXE     43264   8-04-81  12:00a
BASIC    COM     10880   8-04-81  12:00a
BASICA   COM     16256   8-04-81  12:00a
ART      BAS      1920   8-04-81  12:00a
SAMPLES  BAS      2432   8-04-81  12:00a
MORTGAGE BAS      6272   8-04-81  12:00a
COLORBAR BAS      1536   8-04-81  12:00a
BUG      BAS       640   8-04-81  12:00a
CALENDAR BAS      3840   8-04-81  12:00a
MUSIC    BAS      4224   8-04-81  12:00a
DONKEY   BAS      3584   8-04-81  12:00a
BLUE     BAS      1152   8-04-81  12:00a
HUMOR    BAS       640   8-04-81  12:00a
POP      BAS       768   8-04-81  12:00a
FORTY    BAS       768   8-04-81  12:00a
DANDY    BAS       640   8-04-81  12:00a
MARCH    BAS       768   8-04-81  12:00a
STARS    BAS       768   8-04-81  12:00a
HAT      BAS       768   8-04-81  12:00a
SCALES   BAS       640   8-04-81  12:00a
SAKURA   BAS       512   8-04-81  12:00a
CIRCLE   BAS      1664   8-04-81  12:00a
PIECHART BAS      2304   8-04-81  12:00a
SPACE    BAS      1920   8-04-81  12:00a
BALL     BAS      2048   8-04-81  12:00a
COMM     BAS      4352   8-04-81  12:00a
       40 file(s)     144725 bytes
                        6144 bytes free

CHKDSK reports:

          40 disk files
      160256 bytes total disk space
        6144 bytes remain available

Documents

IBM PC Disk Operating System 1.00

Feature Summary

Courtesy of PC DOS Retro:

• distributed on 1 160KB floppy disk
• initial release (equivalent to 86-DOS 1.14)
• released with the IBM PC
• PC DOS system files are IBMBIO.COM and IBMDOS.COM, command shell is COMMAND.COM
• executable file formats are .COM and .EXE
• single-sided 160KB floppy disk support (FAT12)
• directory entries only include the date last written
• file attributes read-only (01h), hidden (02h) and system (04h) supported
• batch files (.BAT) and AUTOEXEC.BAT
• internal commands: COPY, DIR, ERASE, PAUSE, REM, RENAME, TYPE
• external commands: CHKDSK, COMP (PC DOS), DATE, DEBUG, DISKCOMP, DISKCOPY, EDLIN, FORMAT, LINK, MODE, SYS, TIME
• external commands: BASIC, BASICA (PC DOS only)
• special device names: AUX, COM1, CON, LPT1, NUL, PRN
• program loading and execution implemented in COMMAND.COM
• PSP created for each executed program
• files are opened with FCBs
• DPB structures are used for internal drive info
• INT 20h terminate program
• INT 21h DOS API functions 00h-2Dh (18h, 1Ch-20h unused)
• INT 22h termination address
• INT 23h control break handler address
• INT 24h critical error handler address
• INT 25h absolute disk read (implemented in IBMBIO.COM)
• INT 26h absolute disk write (implemented in IBMBIO.COM)
• INT 27h terminate and stay resident (implemented in COMMAND.COM)
• CP/M CALL 0 interface (executes INT 20h)
• CP/M CALL 5 interface supporting INT 21h functions 00h-24h

Summary of Internal Commands

• COPY
  • Copies one or more files to another diskette and optionally, gives the copy a different name if you specify it in the COPY command.
• DIR
  • Either lists all the directory entries, or only lists those for specified files. The information provided in the display for each file includes its size in decimal bytes and the date the file was last written to.
• ERASE
  • Deletes the file with the specified filename from the designated drive, or deletes the file from the default drive if no drive was specified.
• PAUSE
  • Suspends system processing and issues the message Strike a key when ready….
• REM
  • Displays remarks from within a batch file.
• RENAME
  • Changes the name of the file specified in the first parameter to the name and extension given in the second parameter. If a valid drive is specified in the second parameter, the drive is ignored.
• TYPE
  • Displays the contents of the specified file on the screen.

Summary of External Commands

• BASIC
  • Also known as Disk BASIC, this program requires an IBM PC with Cassette BASIC and at least 32Kb of RAM.
• BASICA
  • Also known as Advanced BASIC, this program requires an IBM PC with Cassette BASIC and at least 48Kb of RAM. It includes all Disk BASIC features, along with event trapping, advanced graphics, and advanced music support.
• CHKDSK
  • Analyzes the directory and the File Allocation Table on the designated or default drive and produces a diskette and memory status report.
• COMP
  • Compares the contents of one file to the contents of another file.
• DATE
  • Permits you to enter a date or change the date known to the system. The date is recorded in the directory entry for any files you create or alter.
• DISKCOMP
  • Compares the contents of the diskette in the first drive to the contents of the diskette in the second drive. Usually, you would run DISKCOMP after a DISKCOPY operation to ensure that the two diskettes are identical.
• DISKCOPY
  • Copies the contents of the diskette in the source drive to the diskette in the target drive.
• FORMAT
  • Initializes the diskette in the designated or default drive to a recording format acceptable to DOS; analyzes the entire diskette for any defective tracks; and prepares the diskette to accept DOS files by initializing the directory, File Allocation Table, and system loader.
• MODE
  • Sets the mode of operation on a printer or on a display connected to the Color/Graphics Monitor Adapter.
• SYS
  • Transfers the operating system files from the default drive to the specified drive, in the following order: IBMBIO.COM, IBMDOS.COM.
• TIME
  • Permits you to enter or change the time known to the system. You can change the time from the console or from a batch file.

Additional Utilities

• EDLIN is a line text editor which can be used to:
  • Create new source files and save them.
  • Update existing files and save both the updated and original files.
  • Delete, edit, insert, and display lines.
  • Search for, delete, or replace text within one or more lines.
• LINK is a program that:
  • Combines separately produced object modules.
  • Searches library files for definitions of unresolved external references.
  • Resolves external cross-references.
  • Produces a printable listing that shows the resolution of external references and error messages.
  • Produces a relocatable load module.
• DEBUG is a program that can be used to:
  • Provide a controlled test environment so you can monitor and control the execution of a program to be debugged. You can fix problems in your program directly and then execute the program immediately to determine if the problems have been resolved, You do not need to reassemble a program to find out if your changes worked.
  • Load, alter, or display any file.
  • Execute object files. Object files are executable programs in machine language format.

Notes:

• Directory entries for system files IBMBIO.COM, IBMDOS.COM, and BADTRACK are not listed, even if present.