POST Codes


People are often misled, because they go to the internet and see something like, "List of AMI POST codes", and not realise that AMI/Phoenix/IBM, and the like, changed their POST codes periodically.  Unless you have a list that you know for fact matches the particular BIOS fitted to your motherboard, then you could be being misled.


Example #1

My IBM 5170 motherboard stops at the POST code of 02.  I go to the 'IBM AT BIOS' section of www.bioscentral.com and from there discover that 02 equates to 'BIOS ROM checksum tested'.
But that is wrong, for two reasons:

1. Per here, IBM actually changed the meaning of 02 during the lifetime of the IBM 5170; and
2. Even for the 1985 dated revisions, the description is wrong.  The checksum wasn't tested - it is about to be tested.


Example #2

This is an example of AMI changing the meaning of a code.

According to page 34 of the document at here, the meaning of code 03 differs between AMI's Hi-Flex and AMI's WinBIOS.