Replacements for ST-406/ST-512 drives

[Randy McLaughlin]

From: "Vintage Computer Festival" <vcf at siconic.com>
Sent: Monday, February 07, 2005 10:07 PM
> On Mon, 7 Feb 2005, Scott Stevens wrote:
>
>> You, of course, need to be able to get the drive physically attached to
>> a Linux/whatnot system with the dd command available.  This might not
>> work in many instances with ST-506 or proprietary controllers.  Works
>> great with SCSI though.
>
> As far as I know, Linux can handle MFM drives.
>
> -- 
>
> Sellam Ismail                                        Vintage Computer 
> Festival
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dd works with newer devices that have been remapped and present a "perfect" 
media.

On MFM drives like the 225 the bad spots are in different sponts on 
different drives.  If you use dd it mayl not work if there are any bad spots 
on the replacement drive.

You are also assuming that the HP drive is formatted the same as what you 
format it as for the PC.  For the PC most AT controllers formatted the 
drives the same but not all, if you include all of the 8 bit controllers for 
the PC you end up with dozens of types of formatting, all using 512 byte 
sectors with different skewing.

It would be safer to format the 225 with an AT MFM controller marking bad 
all of the sectors where there is a bad spot on any one.  Next stick it in 
the HP case and see if it recognizes it.  If it doesn't then you need to try 
and find a "perfect" 225 and try dd on it.


Remember that the 506/412 are soft formatted and the formatting was often 
unique from one controller to the next.  After the AT came out many started 
following IBM's lead and the physical formatting tended to be similar to the 
AT.  This was more of following the WD lead plus using 512 byte sectors.


Randy