MS-DOS

~ the eulogy ~

Before any computer in Turkey showed me a desktop, it showed me a drive letter with a backslash behind it and then sat there waiting. That was the middle of the nineties, on borrowed machines in offices and later at school, and nothing happened until you typed the name of something you already had to know was there. MS-DOS offered no menu and no hint about what was on the disk.

Microsoft did not write it. In July 1981 the company paid Seattle Computer Products $25,000 for 86-DOS, which Tim Paterson had put together so that Seattle's 8086 card would have something to run. Microsoft renamed it, licensed it to IBM as PC DOS 1.0, and kept the right to sell its own build to everybody else. That retained right is the reason the next twenty years went the way they did.

Version 1.0 shipped with the IBM PC on 12 August 1981 and understood a single floppy format with no subdirectories at all. 2.0 added directories and a way to address a hard disk. 3.3 handled the 1.44 MB floppy that became the decade's unit of software. 5.0 in 1991 brought a full-screen editor and better use of the memory under the 640 KB line. Version 6.22, in June 1994, was the last one anybody could buy in a box.

After that it stopped being a product and turned into a floor. Windows 95 booted through DOS 7.0 and covered it up. Windows 98 used 7.1. Windows Me shipped 8.0 on 14 September 2000 with the route to a real-mode prompt closed off on purpose, and no version came after it.

~ the dossier ~

~ the memory ceiling ~

640 KB was not a limit anybody defended for long. The IBM PC's address map handed everything above it to hardware, so by the late eighties a machine could have four megabytes installed while DOS refused to put a program into any of it. A small industry grew inside that gap, running from expanded memory boards up to Quarterdeck's QEMM, which people bought for no reason other than freeing another thirty kilobytes.

Games were where it hurt. A CD-ROM driver loaded next to a sound card driver could leave a game short of what it demanded, so you learned to write boot menus into config.sys with a separate entry per title. By 1995 a lot of teenagers could recite the difference between conventional memory and upper memory without ever having read a manual.

~ the compression suit ~

MS-DOS 6.0 shipped in March 1993 with DoubleSpace, which roughly doubled the capacity of a hard disk by compressing it as you wrote to it. Stac Electronics had been selling that exact product as Stacker since 1990 and had shown Microsoft the internals during acquisition talks. A San Diego jury found for Stac in February 1994 and awarded $120 million.

Microsoft pulled the feature, put out 6.21 with no compression at all, then shipped 6.22 with a rewritten DriveSpace that the settlement permitted. The settlement also put $40 million of Microsoft money into Stac as equity. Within two years the price of hard drives had fallen far enough that compressing one stopped being worth the risk.

~ the last version ~

There was no notice. On 31 December 2001 Microsoft's lifecycle table marked versions 1.x through 7.0 unsupported, and 7.10 and 8.0 followed on 11 July 2006. Nobody was going to phone Redmond about DOS 5.0 in either year.

The code came out afterward, which is a better afterlife than most dead software gets. Microsoft released 1.25 and 2.0 through the Computer History Museum in March 2014, put them on GitHub under an MIT license on 28 September 2018, and added version 4.00 on 25 April 2024. The thing that decided what a personal computer was for a decade now reads as a few hundred kilobytes of assembly you can scroll through in a browser tab.

@}-->--

              )
             (_)
            .-'-.
            |   |
            |   |
            |   |
            |   |
          __|   |__   .-.
       .-'  |   |  `-:   :
      :     `---'     :-'
       `-._       _.-'
           '""""""

« previous  ·  random  ·  next »