Amount of Memory Used by MS-DOS (64526)


The information in this article applies to:

  • Microsoft MS-DOS operating system 1.x
  • Microsoft MS-DOS operating system 2.11
  • Microsoft MS-DOS operating system 3.1
  • Microsoft MS-DOS operating system 3.2
  • Microsoft MS-DOS operating system 3.21
  • Microsoft MS-DOS operating system 3.3
  • Microsoft MS-DOS operating system 3.3a
  • Microsoft MS-DOS operating system 4.0
  • Microsoft MS-DOS operating system 4.01
  • Microsoft MS-DOS operating system 5.0
  • Microsoft MS-DOS operating system 5.0a
This article was previously published under Q64526

SUMMARY

Different versions of MS-DOS and different original equipment manufacturers (OEMs) versions of MS-DOS may use slightly different amounts of memory. Depending on the number of floppy drives and hard drive partitions a machine has, MS-DOS uses different amounts of memory. The following list describes the approximate amount of memory used by each MS-DOS version: 
                           Available   Memory
   MS-DOS Version          Memory      Used
   --------------          ---------   ------

   5.0  with Shell
        DOS = HIGH         618K        22K
   5.0  with Shell
        DOS = LOW          574K        66K
   5.0  DOS = HIGH         623K        17K
   5.0  DOS = LOW          579K        61K
   4.0x with Shell         571K        69K
   4.0x                    575K        65K
   3.3a                    586K        54K
   3.3                     586K        54K
   3.2                     595K        45K
   3.1                     602K        38K
   3.0                     602K        38K
   2.11                    616K        24K
   2.1                     616K        24K
   2.0                     608K        32K
   1.1                     627K        13K
These values may be slightly different on your machine because the manufacturer may have modified MS-DOS to function correctly on your machine. This adaptability allows MS-DOS to function identically on many different PCs, giving those manufacturers the flexibility to design machines to meet hardware needs without sacrificing a significant amount of internal memory for the operating system.

MORE INFORMATION

In the list above, each machine was booted with a minimum configuration, no AUTOEXEC.BAT or CONFIG.SYS file, and BUFFERS = 8 by default. MS-DOS 4.0 was booted from the 5.25-inch Operating System 3 disk.
Modification Type:MajorLast Reviewed:11/26/2003
Keywords:KB64526
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