Path: utzoo!attcan!uunet!van-bc!lpami
From: lphillips@lpami.van-bc.UUCP (Larry Phillips)
Newsgroups: comp.sys.amiga
Subject: Re: Quantum SCSI drive and 2090
Message-ID: <1957@van-bc.UUCP>
Date: 19 Nov 88 00:45:22 GMT
Sender: lpami@van-bc.UUCP
Lines: 31


>> For instance, the
>> drive manual states that there are two "zones" on the drive.  The outer
>> zone has 35 sectors/track and the inner zone has 28 sectors per track.
>> Well...the amiga don't know about "zones" so how many sectors per track
>> do you tell prep that it has?  The answer is pretty much anything that
>> adds up to the specified total number of sectors (164,058)...with SCSI
>> controllers the cylinders/surfaces/sectors specifications are somewhat
>> superfluous since SCSI only needs to know what sector you want!
>
>Won't this screw up any optimizations based on knowing what's on
>different cylinders, etc.?  Does ffs do anything like this?

Nope. The File system asks for blocks, contiguous ones if it can, and they
magically come back from the device. In the case of a standard ST506
controller, the driver is the magician, and in the case of a SCSI controller,
the controller is the magician. ie. the command sent at the hardware level
to an ST506 controller contains a cylinder/head/sector calculated by the
driver, and the command sent to a SCSI controller contains a logical
block address.

-larry

--
"Intelligent CPU?  I thought you said Intel CPU!" 
        -Anonymous IBM designer-
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|   //   Larry Phillips                                          |
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