Path: utzoo!mnetor!uunet!husc6!linus!philabs!micomvax!ray
From: ray@micomvax.UUCP (Ray Dunn)
Newsgroups: comp.sys.ibm.pc
Subject: Re: Disk holes and other strange things (was Re: F-15 Strike Eag)
Message-ID: <937@micomvax.UUCP>
Date: 11 Mar 88 23:00:39 GMT
References: <3037@cup.portal.com> <3186@cup.portal.com> <3255@cup.portal.com> <404@mks.UUCP> <1424@puff.cs.wisc.edu>
Reply-To: ray@micomvax.UUCP (Ray Dunn)
Organization: Philips Electronics Ltd. (TDS - Montreal) St. Laurent P.Q., Canada
Lines: 18

In article <1424@puff.cs.wisc.edu> ttang@puff.cs.wisc.edu (Theodore Tang) writes:
>The keyword here is TIMEOUT.  This is exactly what DOS does, it will time,
>not wait for the hole to reappear.  It doesn't have to use the hole, just know
>that it take x usecs for a complete pass and if it hasn't found the desired
>sector by that time, bingo!, you get a TIMEOUT.  This is kind of like when
>you don't close the drive door.
>
>Theodore Tang (Ted) @ University of Wisconsin at Madison
>

RIGHT AND WRONG!!   The *CONTROLLER* uses the index hole to know it isnt
going to find the requested sector on a spinning disk.  Under this
circumstance, an error is returned to DOS which does *NOT* have to wait for
a timeout to occur, the error will be reported within 2 revolution times.
Under other circumstances, when the controller does not give an error return
to DOS, *THEN* DOS will timeout!

Ray Dunn.  ..{philabs, mnetor, musocs)!micomvax!ray