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From: ching@amd.UUCP (Mike Ching)
Newsgroups: comp.sys.mac
Subject: Re: Making *own* SCSI Hard Drive
Message-ID: <4212@amd.UUCP>
Date: Mon, 13-Jul-87 12:51:09 EDT
Article-I.D.: amd.4212
Posted: Mon Jul 13 12:51:09 1987
Date-Received: Tue, 14-Jul-87 06:33:20 EDT
References: <380@umbc3.UMD.EDU> <458@osupyr.UUCP> <19683@ucbvax.BERKELEY.EDU>
Reply-To: ching@amd.UUCP (Mike Ching)
Organization: Advanced Micro Devices
Lines: 48
Keywords: mondo cheap  ibm haters

>>I've never actually seen a SCSI controller, so I don't have any concrete
>>examples of what they cost, but one thing is certain: they're alot more
>>expensive than an IBM standard controller.
>
>Nonsense. On an IBM you start with a drive that already speaks the
>SCSI interface standard. I'll repeat that, because it is important.
>Drives for the IBM PC market already speak the SCSI interface
>standard. 

Not true. IBM drives speak ST506/ST412. There are adapters by Xebec,
Adaptec, DTC, etc. to go from SCSI/SASI to ST506/ST412. There *are*
SCSI drives, eg., Seagate ST225N is a SCSI version of the ST225, but
the majority of drives are ST506/ST412.

>All you need to connect such a drive to a mac is an appropriate cable.
>(The mac has a 25 pin connector, the drive a 50. Half of the drive's
>pins are tied to ground.)  A bare bones SCSI driver is trivial.

The cable is not trivial to construct. It took me over 3 hours to
get it done. Go out and buy one if you do this.

>The extra cost of the packaged Macintosh disk over those bare bargain
>drives goes for:
>1.) a drive power supply
>2.) a case
>3.) software
>4.) service (handling DOA drives, software upgrades
>5.) cables
>6.) profit.

My out of pocket cost was ~$450 and the project took a fair amount
of time. I only did it because when my Relax drive went south, I
couldn't reformat it but had to go back to them for a low level
format (which they did by connecting it to a IBM PC). Not being able
to format my own disk bothers me.

mike ching
Newsgroups: comp.sys.mac
Subject: Re: Making *own* SCSI Hard Drive
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References: <380@umbc3.UMD.EDU> <458@osupyr.UUCP> <19683@ucbvax.BERKELEY.EDU>
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Organization: Advanced Micro Devices
Keywords: mondo cheap  ibm haters