Looking for a ST419

Eric Smith eric at brouhaha.com
Wed Oct 29 20:17:16 CDT 2008


ethan.dicks at usap.gov wrote:
> RWC was important with the ST-506 standard, but, IIRC, it fell
> away with the ST-412 standard, and the pin that the controller
> used to tell the drive to reduce the write current was recycled
> as another head-select line, allowing an ST-412-compatible drive
> to have 9-16 heads.  More modern drives kept track of which track
> they were on and handled RWC internally, sometimes based on the
> Write Precomp value, I think.
>   
Yes, ST-412 interface drives did RWC internally, if they needed it, but 
they decided based on maintaining their own cylinder counter.  It was 
unrelated to any write precomp cylinder threshold in the controller 
settings, since the drive had no practical way to know what the precomp 
setting was.

Eric




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