MS-DOS 1.0

 MS-DOS (Microsoft Disk Operating System), originally known as 86-dos or dos it is Microsoft's first operating system that was released in August 1981 for x86-based personal computers and also for business computers.

Birth and Evolution In 1981

IBM released its first personal computer (IBM PC), and with it came PC-DOS 1.0. This early version supported only floppy disks. However, in 1982, Microsoft acquired 86-DOS, reworked it, and unleashed MS-DOS 1.0. This marked the beginning of a transformative journey.

It comes with 16KB-64KB of ram and the maximum ram support was 640KB.

Meet the Prompt

MS-DOS was all about the command line. No fancy icons, no mouse clicks—just you, your keyboard, and a blinking cursor. It was like having a secret handshake with your computer. You’d type in commands like Want to list files? DIR. Need to copy files? COPY. It was all about commands.

Features of MS-DOS 1.0:

• Application Launch: MS-DOS 1.0 could start applications in .COM and .EXE formats.
• Batch Processing: It processed batch files (those with .BAT extensions).
• File System: It worked with 160KB floppies but didn’t support folders (all files had to reside in the root directory).
• Commands: The command interpreter supported basic commands like DIR, TYPE, COPY, ERASE, RENAME, PAUSE, and REM.
• Limitations: No pipes, redirection, or device drivers were supported.

The Origins

• 86-DOS: Tim Paterson’s creation, 86-DOS, was a humble clone of CP/M, designed for the 8086-based hardware. It caught the attention of Microsoft, which acquired it and licensed it to IBM for their groundbreaking IBM PC.
• PC-DOS 1.0: The first official release, PC-DOS 1.0, debuted alongside the IBM PC in August 1981. It supported only floppy disks and lacked subdirectories or hard disk support.

MS-DOS 1.25 and Beyond

• MS-DOS 1.25, equivalent to PC-DOS 1.10, was the first version licensed to OEMs beyond IBM. Vendors often labeled their versions differently, but most were based on MS-DOS 1.25.
• Installation Challenges: Some OEM versions were specific to particular hardware configurations. Special disk formats or drive hardware (like 8" floppy drives) were required.
• Legacy and Source Code: The legacy of MS-DOS lives on. In 2014, the Computer History Museum released the source code for MS-DOS 1.1 and 2.0 for non-commercial use. You can even explore the disassembled and commented source code on GitHub.