Source of the original MS DOS. (1)

Written by Tim Paterson at Seattle Computer Products.

- For Intel 8086
- Written in about 2 months
- 6K code
- Internal name: QDOS, Quick and Dirty Operating System

- Some influence from and advanced MS BASIC that used disk storage
- Used same internal function calls as CP/M
- Used 8086 addresses and conventions published by Intel to make it easy to run 8080 programs on the 8086
- Used CP/M type commands (Type, Rename, Erase, ...)
- Retained the CP/M BIOS idea
- However, it was not just an extension of CP/M
- Address more memory
- File allocation tables
- Tree of directories and subdirectories

Notes

1. Paul E. Ceruzzi, A History of Modern Computing, 2nd ed. (Cambridge, MA: MIT Press, 2003), 270-71.

Bibliography

"Origins of MS-DOS," http://www.patersontech.com/Dos/ (Paterson Technology, accessed 2004 Nov 19). This collection has several original documents.