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From: jcm@mtunb.ATT.COM (John McMillan)
Newsgroups: comp.sys.att,unix-pc.general
Subject: Re: hard disks for 3b1
Message-ID: <1704@mtunb.ATT.COM>
Date: 22 Nov 89 16:48:53 GMT
References: <1727@ncrcce.StPaul.NCR.COM> <1145@becker.UUCP>
Reply-To: jcm@mtunb.UUCP (John McMillan)
Organization: AT&T ISL Middletown NJ USA
Lines: 42


	By now Bruce has probably had some sleep and begun to regret
	his posting:

In article <1145@becker.UUCP> bdb@becker.UUCP (Bruce Becker) writes:
:
>	In general, any drive which works with a
>	standard IBM XT or AT controller with a
>	ST-506 interface ought to work fine. You
>	can't reference more than 1024 tracks without
>	the P5.1 upgrade, and you can't reference
>	more than 8 heads without the WD2010. The

	- P5.1 supports 9 -> 16 heads
	- WD2010 supports 1025 -> 2047 heads
	- Note that early kernels (3.0? 3.5?) may not support
		> 1024 cylinders.

>	chip doesn't require the upgrade, & the upgrade
>	doesn't require the chip. It is possible to use
>	RLL drives but you will only get 2/3 of the
>	rated capacity, since the tracks will be
>	formatted with only 17 512-byte sectors.

	- _I_ wouldn't use RLL, but lack details.  It is my
		recollection that the electronics just ain't
		THE SAME and at least boundary-condition
		problems might occur.  (Go ask someone who KNOWS
		-- NOT ME.)

>	It would be useful for people to post any
>	known exceptions to this generality.

	- The WD chip registers are set for write-pre-compensation
		at cylinder 128.  How sensitive your disk is to
		this ain't my concern!-)

Geee... I think this posts exceptions to all-but-one statement, Bruce!-)

john mcmillan -- att!mtunb!jcm -- speaking for self, not THEM
		(And rushing off for lamb vindaloo without reviewing
		the nonsense I've posted above.)