From: sean@coombs.anu.edu.au (Sean Sebastian Batt)
Newsgroups: comp.sys.hp
Subject: Re: How does 'mediainit -G' (guru mode :-) work?
Date: 20 Dec 92 10:36:29 GMT
Organization: Australian National University
NNTP-Posting-Host: 150.203.76.2

In comp.sys.hp article <5570919@hpfcdc.fc.hp.com> Paul Perlmu;er wrote:
>Please DO NOT use GURU mode.

OK, then please tell me how I can reformat any SCSI disc for 1024
bytes per sector. Pretend it's an HP disc, like a Micropolis 1528.

>Using unsupported disks (or non-referenced disks) must be done with care,
>and with a full understanding that you do so at your own risk.

I know, I know. I said I understood that in my post.

>Most times you will be able to plug in a third-party disk and
>successfully use it.

Thank heavens! We can't afford HP "qualified" peripherals, even at a
hefty academic discount. If I suggested that pay HP's price for discs
my boss would have a fit. He'd wonder why 3rd party discs weren't
appropriate for HP gear when they work fine on Suns, DECStations,
Macs, IBM PClones, etc., etc. Maybe then he'd wonder why I recommended
HP gear when the after sale upkeep was so much greater that other
competing products.

(I'm employed on a 12 month contract and would like to keep my boss
happy so it will be renewed. Wish me luck! :-)

>Mediainit *may* work. You will have to make a new entry in
>/etc/disktab (which has a set of instructions for doing so, at the
>beginning of the file).

Mediainit doesn't look at /etc/disktab, does it?

>HP goes to a lot of effort to qualify peripherals.

I'm sure they do. When I can afford to buy HP hardware exclusively,
I'll probably do so. I'll need to win a lottery, though :-)

>Because you hook up a disk and can access it doesn't at all mean it
>works!

Because it isn't an HP "qualified" disc and I can access it, doesn't
mean that it's broken, either!

>E.g. what happens if their are two disks on the system and they have
>a funny interaction problem that occurs only once every several
>thousand transfers? I've seen that several times.

Then there's a bug. In the disc firmware? In the HP controler? In
HPUX? If the disc works on Suns, IBMs, Macs, etc, won't HP be
interested in the problem? Sure, I won't expect a fix; it's an
unsupported disc! But at least I'd know that the disc worked.

>A good starting point is to carefully read the disk's documentation.

A starting point for WHAT? I just want to re-low-level-format a disc.

>Also, the drive's manufacturer may have experience with your
>configuration.

Really, the drive's manufacturer has done enough.

>If you can access it from your system, try running simple tests, such
>as read / write tests.  Also study the performance, since that may
>give valuable information about how well the drive is working.

This doesn't have a lot to do with what I'm attempting, but will
probably be the subject of my next post.

>Cheers,
>Paul Perlmutter

Thanks anyway, Paul.

>PS. A very common and popular myth is that SCSI peripherals are "plug and play"
>compatible.  Don't believe for a minute.

Good advice.

Sean Batt

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------------- Sean Sebastian Batt - sean@coombs.anu.edu.au --------
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