Xref: utzoo comp.sys.mac:50917 comp.sys.mac.hardware:2358
Path: utzoo!attcan!uunet!cs.utexas.edu!uwm.edu!bionet!ames!sun-barr!decwrl!shelby!neon!Kermit.Stanford.EDU!philip
From: philip@Kermit.Stanford.EDU (Philip Machanick)
Newsgroups: comp.sys.mac,comp.sys.mac.hardware
Subject: Re: SE/30 with (bad) 40mb disk
Message-ID: <1990Mar19.181842.15306@Neon.Stanford.EDU>
Date: 19 Mar 90 18:18:42 GMT
References: <22519.2602bdeb@kuhub.cc.ukans.edu> <1990Mar15.145401.17551@aucs.uucp>
Sender: news@Neon.Stanford.EDU (USENET News System)
Reply-To: philip@pescadero.stanford.edu
Distribution: na
Organization: Computer Science Department, Stanford University
Lines: 16

In article <22519.2602bdeb@kuhub.cc.ukans.edu>,
kudlacek@kuhub.cc.ukans.edu writes:

> The actual problem was that these drives were sticking and not 
> getting enough torque at startup to move the heads... The ROM fix
> increases a voltage (or current?) to give the stepper motor more
> uumph. Additionally, the ROM invokes a periodic head sweep during
                                         ^^^^^^^^^^^^^^^^^^^
> normal operation to keep the lubricant slippery. Neat idea huh!

I've often wondered why my Mac would every now and then do a disk access
when it was supposed to be idle. Could this be the reason (I'm not only talking
about Apple HDs here: I've also had this with a Quantum 105M).

Philip Machanick
philip@pescadero.stanford.edu