Codes of versions 1.1 and 2.0 of MS-DOS are published by Museum

The Computer History Museum released Tuesday (25) the source code and documentation files from older versions of MS-DOS, the first operating system sold by Microsoft for IBM-PC computers in 1981, and also the code of Word 1.1a for Windows, released in 1991.

Created for use on personal computers that IBM was developing, MS-DOS was a simple operating system that worked through commands. Unlike what was normal at the time, IBM decided to outsource the development of the system. For now is creating compilers and interpreters for computer IBM, Microsoft ended up being the chosen company, but the company did not have a system to sell.

Microsoft licensed 86-DOS system developed by Tim Paterson for Seattle Computer Products (SCP), paying a total of $ 75,000 at the time: $ 25K for an initial license and $ 50,000 for the full rights of software that Microsoft decided to sell to manufacturers of IBM PC clones (in a process 1986, Microsoft ended up having to pay a total of $ 1 million).

Once hired by Microsoft, Paterson noted that the SCP did not know that IBM was developing the computer on which the system would be used. PC DOS 1.0, IBM rescheduled for MS-DOS 1.0 version was released in 1981.

Since version 2.0, with some extra features, such as support for subdirectories and hard drives was launched in 1983. This was an evolution since the PC-DOS 1.0 diskettes just read. o The latest version of MS-DOS is 8.0, used in Windows ME and boot disks created by Windows XP.The last “pure” version of MS-DOS is 6.2.2, released in 1994. Have the latest version of PC DOS, 7.10, was released in 2003.

According to the “Computer History Museum”, not even Microsoft still had the source code for these systems. The code for version 1.1 was delivered personally by Paterson, while version 2.0 was in the personal collection of Len Shustek, director of the museum. Roy Levin, director of Microsoft Research Center in Silicon Valley, was responsible for obtaining permission which allowed the publication of codes.

The code of Word 1.1a for Windows is supplied by Microsoft itself. Unlike DOS, which was entirely programmed in “Assembly” language, the Word already has files in the C programming language

The codes were made ​​available for non-commercial use and may be downloaded from the Computer History Museum website ( go here ).