The Origins of MS-DOS

1. The Origins of MS-DOS Sui-Tung Ng CS 8422, Spring 2003 Advanced Computing Systems

2. Tim Paterson - Original author of MS-DOS - graduated from U of Washington in 1978 - worked as an engineer in Seattle Computer Products - designed an 8086 CPU card for S-100 Bus in May 1979 - began designing DOS in 1980 after IBM had released their new 8086 microprocessor (16-bit) objectives in design of DOS - as simple as possible - make it fast and efficient - written in 8086 assembly language In college, Paterson wrote a multi-tasking operating system for the Z80 microprocessor as a term project. Therefore, Paterson had confidence in writing an OS for 8086 computer. Patterson spent half of his time working on Qdos from April to July, 1980. QDOS was completed in July, 1980. Tim Paterson

3. took two man-months to create Quick and Dirty Operating System (QDOS) used Microsoft Stand-Alone Disk BASIC to handle file organization was hired in Microsoft in 1981 in and out of Microsoft in 1980s joined Microsoft again in 1990 QDOS could work with Microsoft Stand-Alone Disk BASIC that used a File Allocation Table (FAT). Tim Paterson

4. located in Tukwila of Washington manugacturer of S-100 memory cards a hardware company, not software company, in 1980 worked with Microsoft and Digital Research shipped its first 8086 cards with Microsoft Stand-Alone Disk BASIC in Nov 1979 gave up to use Digital Research CP/M-86 as its operating system in 1980 decided to create its own DOS Seattle Computer Products (SCP) gave up to use CP/M-86 as Digital Research could not promise when it would be completed. Finally, SCP decided to develop its own DOS. Seattle Computer Products

5. QDOS - completed in July 1980 QDOS 0.10 - launched in Aug 1980 86-DOS version 0.3 - released at the end of 1980 sold non-exclusive rights to Microsoft to market 86-DOS released 86-DOS version 1.00 in Apr 1981 similar to the MS-DOS of today Seattle Computer Products (SCP)was a hardware company, therefore it was willing to sell the non-exclusive right for Microsoft to market its 86-DOS at that time. Seattle Computer Products

6. Microsoft had been working with IBM on their personal computer project and advised IBM to Digital Research for the operating system. However Digital Research refused to sign a non-disclosure agreement. Finally, Microsoft offered IBM with DOS by buying the rights to market DOS from SCP. Microsoft • paid SCP $10,000 for the right to market 86-DOS and • paid SCP $15,000 for each OEM customer in 1981 • got a secret customer for DOS - IBM • bought DOS from Seattle Computer by paying $50,000 • plus a license to include DOS in their PCs in July 1981 • named DOS as MS-DOS • provided 86-DOS1.14 as OS in IBM’s PCs • released MS-DOS version 1.24 to IBM • released MS-DOS version 1.25 to the public in Mar 1982

7. Microsoft kept improving and evolving DOS after buying the products completely from SCP. MS-DOS became a very popular Operating System in the PC markets. Microsoft • released MS-DOS version 2.0 to IBM new XT computer in Feb 1983 • settled the license dispute by buying the license back from SCP for $975,000 in 1986 • the total price for DOS ended up $1,050,000 • launched MS-DOS to its OEM in 1982 • kept improving and evolving DOS for 15 years • stopped updating DOS until Windows95 was released in 1995

8. Year DOS Version 12/1980 QDOS 07/1981 86-DOS 09/1982 MS-DOS 1.25 03/1983 MS-DOS 2.0 11/1983 MS-DOS 2.01 12/1983 MS-DOS 2.11 09/1984 MS-DOS 3.0 11/1984 MS-DOS 3.1 04/1986 MS-DOS 3.2 MS-DOS Timeline

9. 04/1987 MS-DOS 3.3 04/1988 MS-DOS 3.31 07/1988 MS-DOS 4.0 11/1988 MS-DOS 4.01 04/1989 MS-DOS 4.01a 04/1991 MS-DOS 5.0 03/1993 MS-DOS 6.0 11/1993 MS-DOS 6.2 04/1994 MS-DOS 6.22 08/1995 MS-DOS 7.0 Above timeline shows that Microsoft spent time to develop and market the MS-DOS from 1980 to 1995. The development cost of MS-DOS was high over the past 15 years. MS-DOS Timeline

10. Tim Paterson was the original author in DOS MS-DOS was an easy-to-use operating system Microsoft successfully launched MS-DOS to IBM and to the PC market Microsoft kept improving and evolving the MS-DOS over the past years Microsoft integrated MS-DOS with its windows operating system in 1995 Without the efforts of Microsoft, DOS will not be the popular operating system in 1980s and 1990s. MS-DOS now is integrated in Windows 95, 98, NT, and 2000. Conclusion

11. References A short history of MS-DOS. (2003). Retrieved February 21, 2003, from http://www.patersontech.com/Dos/Byte/History.html. Conner, D. (1998). Father of DOS still having fun at Microsoft. Retrieved February 21, 2003, from http://www.patersontech.com/Dos/Micronews/paterson04_10_98.htm. DOS timeline. (2003). Retrieved February 21, 2003, from http://www.powerload.fsnet.co.uk/timeline.htm. Hunter, D. (2003). Retrieved February 21, 2003, from http://www.patersontech.com/Dos/Softalk/Softalk.html.

12. References MS-DOS review. (2003). Retrieved February 21, 2003, from http://www.michaelh.com/comp/msdos.shtml. Paterson, T. (2003). DOS. Retrieved February 21, 2003, from http://www.patersontech.com/Dos/Encyclo.htm. The Dross of the DOS. (1997). Retrieved February 21, 2003, from http://www.forbes.com/asap/1997/1201/070_print.html.