Date   : Tue, 05 Dec 2006 12:34:28 +0000 (WET)
From   : PCOGHLAN@... (Peter Coghlan)
Subject: how can I test if the 1770 and 8271 disc interface

 
To: 

>
>Any one have any ideas on how to do the above?
>
>Just to be clear I can check the dfs by doing a checksum and comparing it to 
>another or previous value but how about the 8271 FDC? The problem is that I 
>dropped it and although it seems to work fine I have some software which 
>makes full use of this but if damaged the data will be meaningless. The FDC 
>itself cannot be detected and so a checksum not possible and has more than 
>the standard legs.
>
>Is it ppossible to do a checksum on a pc compatible programmer that can 
>accomodate the larger sized rom and compare values from 2 different roms?
>

The DFS is a ROM. Because a ROM holds data, it is possible to checksum it
to check if the data is correct.

The 8271 and 1770 are not ROMs, they are disk controllers. They do not
contain data which can be checksummed so they cannot be checked in this
way.

Unless it was dropped very hard, the 8271 is not likely to be damaged
much by the fall. It might have bent some of the pins. If the pins can be
straightened out without breaking them, it should be ok.

If you can format a disk, write files to it until it is full and then
read them back correctly without errors, the disk controller is likely to
be ok. I can't think of any better test at the moment.

Regards,
Peter.