---
layout: page
title: PC-DOS 1.00
permalink: /disks/pcx86/dos/ibm/1.00/
redirect_from:
  - /disks/pc/dos/ibm/1.00/
machines:
  - type: pcx86
    id: ibm5150-pcdos100
    config: /devices/pcx86/machine/5150/mda/64kb/machine.xml
    autoMount:
      A:
        path: /disks/pcx86/dos/ibm/1.00/PCDOS100.json
---

PC-DOS 1.00
---

The PCjs machine below is running PC-DOS 1.00.

{% include machine.html id="ibm5150-pcdos100" %}

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).

PC-DOS 1.00 was released on one single-sided (160Kb) diskette.  A complete listing of all the files is shown below. 

### Directory of PC-DOS 1.00 Diskette

	IBMBIO    COM        1920  07-23-81
	IBMDOS    COM        6400  08-13-81
	COMMAND   COM        3231  08-04-81
	FORMAT    COM        2560  08-04-81
	CHKDSK    COM        1395  08-04-81
	SYS       COM         896  08-04-81
	DISKCOPY  COM        1216  08-04-81
	DISKCOMP  COM        1124  08-04-81
	COMP      COM        1620  08-04-81
	DATE      COM         252  08-04-81
	TIME      COM         250  08-04-81
	MODE      COM         860  08-04-81
	EDLIN     COM        2392  08-04-81
	DEBUG     COM        6049  08-04-81
	LINK      EXE       43264  08-04-81
	BASIC     COM       10880  08-04-81
	BASICA    COM       16256  08-04-81
	ART       BAS        1920  08-04-81
	SAMPLES   BAS        2432  08-04-81
	MORTGAGE  BAS        6272  08-04-81
	COLORBAR  BAS        1536  08-04-81
	BUG       BAS         640  08-04-81
	CALENDAR  BAS        3840  08-04-81
	MUSIC     BAS        4224  08-04-81
	DONKEY    BAS        3584  08-04-81
	BLUE      BAS        1152  08-04-81
	HUMOR     BAS         640  08-04-81
	POP       BAS         768  08-04-81
	FORTY     BAS         768  08-04-81
	DANDY     BAS         640  08-04-81
	MARCH     BAS         768  08-04-81
	STARS     BAS         768  08-04-81
	HAT       BAS         768  08-04-81
	SCALES    BAS         640  08-04-81
	SAKURA    BAS         512  08-04-81
	CIRCLE    BAS        1664  08-04-81
	PIECHART  BAS        2304  08-04-81
	SPACE     BAS        1920  08-04-81
	BALL      BAS        2048  08-04-81
	COMM      BAS        4352  08-04-81

CHKDSK reports:

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

Additional Information From [PC DOS Retro](https://sites.google.com/site/pcdosretro/doshist)
---

- 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

See [PC-DOS 1.00 Documentation](/pubs/pc/software/dos/PCDOS100/) for more information.