Path: utzoo!attcan!uunet!super!udel!rochester!cornell!uw-beaver!tektronix!tekcrl!tekfdi!videovax!stever
From: stever@videovax.Tek.COM (Steven E. Rice, P.E.)
Newsgroups: comp.sys.amiga.tech
Subject: Re: Request to Commodore (Bad Blocks)
Keywords: trackdisk.device
Message-ID: <5234@videovax.Tek.COM>
Date: 28 Sep 88 19:16:46 GMT
References: <8891@cup.portal.com> <5660018@hpcvca.HP.COM> <40244@linus.UUCP>
Reply-To: stever@videovax.Tek.COM (Steven E. Rice, P.E.)
Organization: Tektronix Television Systems, Beaverton, Oregon
Lines: 24

In article <40244@linus.UUCP>, Robert I. Eachus (eachus@mitre-bedford.arpa)
was commenting on a suggestion to begin floppy disk writes at the index
hole when he wrote:

> . . . Right now, trackdisk.device must rewrite an entire track even if
> only  one sector is   changed, and more  important  must  read a track
> completely to write one  sector.   If a "smart" trackdisk.device knows
> where sectors  are located,  it  can do  single  sector writes  in  an
> average of 0.7 rotations,  instead of 2.2.  . . .

Nope.  In order to get 880K bytes on a disk (instead of 720K), trackdisk
writes 11 sectors in succession, *without* the intersector gaps that are
found in the "normal" (i.e., 720K) format.  Attempting to write a single
sector would result in trashing the end of the previous sector or the
beginning of the next, depending on the relative timing of the write
to that of the previous ones.  Thus, it is still necessary to both read
and write a track at a time.

					Steve Rice

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