Perstor Disk Drive Controllers

[Larry Snyder]

In article <614 at sixhub.UUCP>, davidsen at sixhub.UUCP (Wm E. Davidsen Jr) writes:
> 
>   Trust me, that's not how it works. Any form of RLL does not "make the
> drive spin faster" not does it "put the bits closer together." It gets
> compression by putting the bits farther apart and measuring the distance
> between them more closely.
> 
>   A drive which is marginal MFM may be unusable RLL when it gets a
> little hotter than normal, but NOT because it's spinning faster. The
> drive spins even with no controller at all.

A couple of months ago I added another controller (1542) and a large
SCSI drive to my existing controller/drive combination - and like
most of the midwest - we have been experiencing a "heat wave".  Along
with this heat (in the 90's in the computer room) read errors started
appearing on the SCSI drive - and after removing the cover off the 
box the SCSI drive is too hot to touch.  With the 50 conductor ribbon
cable it's hard to keep from blocking the air flow into the power
supply for the fan to shove out - but I tried :).  I also replaced
the fan in the PS with one that moves more air - and likewise placed
a fan in the front of the machine which is sucking air in and blowing
in over the boards in the expansion slots.

Reference the perstor boards - I have heard many stories of them
actually destroying drives by pushing the electronics beyond specs.

Miniscribe, Seagate, CDC - none of the vendors certify their
products for use with the Perstor cards - and as a matter of fact,
the Perstor products actually decrease the transfer rate (matched
against a 1:1 MFM or RLL controller) with data throughput running
around 300 kb/sec.

If you value your data and hardware - run them with approved controllers.


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