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From: rick@tmi.com
Newsgroups: comp.sys.amiga.misc
Subject: Re: ST157N Drives
Message-ID: <4991@tmi.com>
Date: 24 May 91 09:41:23 GMT
References: <467@regina.uregina.ca>
Organization: Technology Marketing Inc., Irvine, CA
Lines: 37

In article <467@regina.uregina.ca>, plummer@hercules.cs.uregina.ca (Dave Plummer) writes:
> I'm having some trouble trying to figure out how the hard drive geometry
> is represented.  My ST157N drive _should_ have 94860 blocks.  That's
> 94548 data + 2 reserved + 310 reserved for HardBlocks.  That it does.
>  
> If you look at the aparrent SCSI geometry, that's 155 * 612 cylinders.
> That's what I expected.  Now the question:  what kind of drive has 155
> sectors per track?  That's _not_ 0-155, that's 155 per track.  Is one
> reserved by SCSI as a spare?  Is that a function of the drive or the
> A2091?  How do you determine if/how many are set aside?  Is it always
> one?
>  
> Could this be what the rdb_CylBlocks field represents?

According to one of my lists, the ST-157N and ST-157N-1 have the following
geometry:

    Form Factor:    3.5"
    Capacity:       48MB
    Cylinders:      613
    Heads:          6
    Sectors/Track:  26
    Encoding:       RLL
    Max. XFer.:     10MB/S (Sure. Uh huh! Right. I believe that. 8-)
    Seek Time:      40ms (157N), 28ms (157N-1)

I hope that helps.  As to how they determined a maximum transfer rate of
10MB/s, I have no idea.

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|[- O] Rick Stevens                                                        |
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