Not to be confused with the multitasking MS-DOS 4, a separate version released by Microsoft to a limited number of OEMs in 1986.
Version of MS-DOS
Preliminary nameMS-DOS 3.40
Release date1988-07
Replaced by

MS-DOS 4 is a a version of MS-DOS released in 1988. This is the only version of DOS to be developed primarily by IBM prior to the collapse of the Microsoft–IBM collaboration. It includes significant improvements to the user experience, such as a full screen installation wizard, and the MS-DOS Shell. Support for drives larger than 32 MB has been added (although already implemented in previous versions by some OEMs), allowing partitions with sizes up to the FAT16 limit of 2 GB. MS-DOS 4 also includes EMM386, a memory manager that leverages features of the i386 processor to grant access to memory beyond the first megabyte addressable in real mode.

The original version, MS-DOS 4.00, was released in July 1988, had a short shelf life and is quite rare nowadays. It was replaced by MS-DOS 4.01 in November 1988 due to 2 major bugs both in the shell and the memory manager. There is also a separate version of MS-DOS, also version 4.0, that was produced by Microsoft around 1986 and supports pre-emptive multitasking, but is completely unrelated to this version.

New features and changes[edit | edit source]

  • Support for EGA and VGA display adapters.
  • Support for FAT16 partitions larger than 32 MB.
  • Support for the LIM / EMS standard (driver EMM386.SYS, access to additional memory on 386-based systems and higher), which allowed individual parts of the operating system to load into additional memory.
  • Drastic improvements in functionality with the Select installation program. It now automatically creates the appropriate CONFIG.SYS and AUTOEXEC.BAT files.
  • The introduction of a new MEM command, which allows users to analyze the current memory configuration.
  • Four countries were added in the list of supported regions.
  • Graphic printing was added.
  • Various new features in existing commands, which includes: TREE, DELETE, MODE, APPEND, FASTOPEN, NLSPUNC, ATTRIB, FDISK, REPLACE, BACKUP, GRAFTABL, SELECT, COUNTRY, GRAPHICS.
  • Improved system drivers, including: ANSI.SYS, DRIVER.SYS, DISPLAY.SYS, PRINTER.SYS.
  • MS-DOS Shell was added.
  • The SELECT program for setting up DOS on a hard disk has been transformed into a full-fledged setup wizard. Keyboard layout and install directory are now specified inside of the wizard rather than as parameters specified for SELECT.

History[edit | edit source]

Initially, the project was named "MS-DOS 3.40", and under this name was mentioned in the September 1988 issue of Serbian computer magazine Svet Kompjutera,[1] as well as in a contract between Microsoft and Zenith Data Systems from August 1987.[2]

MS-DOS 4.00 was released in July 1988, only to be replaced by MS-DOS 4.01 in November 1988 due to major bugs in the shell and in the memory management system. MS-DOS 4.02 was also mentioned in an antitrust document called PX05132, however, if existing, it is yet to be found.[3]

List of known OEM releases[edit | edit source]

MS-DOS 4.00[edit | edit source]

  • RM Nimbus
  • Sampo

MS-DOS 4.01[edit | edit source]

  • AGI
  • Amstrad
  • AST
  • Bondwell
  • Emerson
  • HP
  • Inves
  • Mitac
  • Olivetti
  • Packard Bell
  • Philips
  • Phoenix
  • RM Nimbus
  • Sharp
  • Trigem
  • Tulip
  • Twinhead
  • Zenith

MS-DOS 4.01a[edit | edit source]

  • Nokia
  • Victor

MS-DOS 4.01d[edit | edit source]

  • Compaq

Gallery[edit | edit source]

MS-DOS 4.00[edit | edit source]

MS-DOS 4.01[edit | edit source]

References[edit | edit source]