About Config.Sys in OS/2

As an OS/2 user, I have struggled to understand how the Config.Sys file controls the operation of OS/2 on the computer. I understand that over half of the code in the OS/2 kernel has to do with processing the Config.Sys file.


The Config.Sys file is a plain text file organized line by line. The file is not simply read and processed however. The kernel reads Config.Sys several times, looking for different lines on each pass.

Config.sys scan order

  1. PSD
  2. BaseDev
    • SYS
    • ADD
    • DMD
  3. Device and IFS

    Note: Always put Mac after IFS except NETWKSTA

  5. General statements
Last Modified: 20 Nov 2019
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