Originally 86-DOS, written by Tim Paterson of Seattle Computer Products, DOS was a rough clone of CP/M for 8086 based hardware. Microsoft purchased it and licensed it to IBM for use with Microsoft's IBM PC language products. In 1982, Microsoft began licensing DOS to other OEMs that ported it to their custom x86 hardware and IBM PC clones.

For IBM-specific releases, please see the IBM PC-DOS product page.

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DOS 1.x was very limited in what it could do. It could start applications (.COM and .EXE), and process batch files (.BAT). DOS 1.0 worked with 160KB floppies and did not support folders (all files had to be in the root). The command interpertor supported the following commands:

  • DIR, TYPE, COPY, ERASE, RENAME
  • PAUSE, REM

No pipes, redirection, or device drivers were supported. The DOS API in 1.0 was very limited.

MS-DOS 1.25, the equivalent of PC-DOS 1.10, was the first version licensed to OEMs beyond IBM or Seattle Computer Products.

Some vendors labeled their versions of MS-DOS with different names and version numbers. All of the versions here are believed to be based off of MS-DOS 1.25, even if the vendor called it something else.

Important: Many of these OEM versions will only run on the specific computers they were designed for. Others may boot on an IBM PC, but certain devices or tools may not operate. Some require special disk formats or drive hardware, such as 8" floppy drives.

Most of these images need to be written with ImageDisk, or some other DOS based disk writer. WinImage can not handle the file system on most DOS 1.x disks.

Those that are compatible with the IBM PC (Such as the Columbia Data Products OEM) can be mounted and booted in an emulator such as MESS or PCE.

Please see the documentation included with each for specifics.

Wanted: Eagle 1600 MS-DOS 1.25 with hard disk diag disk.


Stats/Requirements

Category: Operating System
Platform: DOS
Release: 1981
End of Life: Unknown
RAM: 32 KB
Disk Space: 160 KB
Required CPU: Intel 8088 4.77MHz
Type: Graphical

Downloads

Name Version Size Language Architecture Contents
MS-DOS 1.25 (Z-DOS) (5-27-1983) [Zenith Z-100] (5.25-320kb)  1.25 (Z-DOS) (5-27-1983) [Zenith Z-100] 371.87 KB English x86 5.25" Floppy
MS-DOS 1.25 (Z-DOS) (8-11-1983) [Zenith Z-100] (5.25-320kb)  1.25 (Z-DOS) (8-11-1983) [Zenith Z-100] 419.81 KB English x86 5.25" Floppy
MS-DOS 1.25 [CDP OEM R2.11] (5.25-320k)  1.25 [CDP OEM R2.11] 399.9 KB English x86 5.25" Floppy
MS-DOS 1.25 [CDP OEM R2.11] Manual   1.25 [CDP OEM R2.11] 25.56 MB English x86 File Archive
MS-DOS 1.25 [Compaq OEM r1.11] (5.25-160k)  1.25 [Compaq OEM r1.11] 174.53 KB English x86 5.25" Floppy
MS-DOS 1.25 [Compaq OEM r1.12] (5.25-320k)  1.25 [Compaq OEM r1.12] 114.3 KB English x86 5.25" Floppy
MS-DOS 1.25 [Corona Data Systems OEM (BIOS 1.03)] (5.25-320k)  1.25 [Corona OEM (BIOS 1.03)] 67.48 KB English x86 5.25" Floppy
MS-DOS 1.25 [Corona Data Systems OEM (BIOS 1.07)] (5.25-320k)  1.25 [Corona OEM (BIOS 1.07)] 129.5 KB English x86 5.25" Floppy
MS-DOS 1.25 [Micromint MPX-16] (5.25-160k)  1.25 [Micromint MPX-16] 129.46 KB English x86 5.25" Floppy
MS-DOS 1.25 [SCP OEM] [SCP Cromemco S-100] (8-inch DSDD)   1.25 [SCP OEM][SCP Cromemco S-100] 435.34 KB English x86 File Archive
MS-DOS 1.25 [SCP OEM] [SCP Tarbell S-100] (8-inch SSSD)  1.25 [SCP OEM] [SCP Tarbell S-100] 308.68 KB English x86 File Archive
MS-DOS 1.25 [Sanyo MBC-550 OEM r1.00] (5.25-160k)  1.25 [Sanyo MBC-550 OEM r1.00] 112.21 KB English x86 5.25" Floppy
MS-DOS 1.25 [TI Professional Computer OEM r1.13] (5.25-320k)  1.25 [TI Professional Computer OEM r1.13 206.99 KB English x86 5.25" Floppy
MS-DOS 1.25 [TI Professional Computer OEM r1.13] Manual  1.25 [TI Professional Computer OEM r1.13 36.07 MB English x86 File Archive
MS-DOS 1.25 [Zenith Z-100 PC] (5.25-320kb)  1.25 [Zenith Z-100 PC] 62.72 KB English x86 5.25" Floppy
MS-DOS 1.25 for Commodore CBM B Series  1.25 for Commodore CBM B Series 90.65 KB English x86 File Archive