Re: GCR specification - where?

[shoppa@alph02.triumf.ca (Tim Shoppa)]

In article <5dtns1$ajp@staff.cs.su.oz.au>,
Fred the Wonder Worm <ftww@cs.su.oz.au> wrote:
>
>I've recently unearthed my Apple ][+ and was somewhat surprised to find
>that everything was in working order (I did clear the spiders out of the
>case first, though).  Anyway, I want to find out precisely how the data
>is laid out on the disk; much searching through FAQs and various other
>places has revealed little more than that GCR (group code recording) is
>used.
>
>So now what I want is a description of how data is organized on the disk
>under GCR, and how this is translated into bytes to move into memory.
>Obviously I could look at RWTS, but it's likely I would misunderstand
>something, and in any case the timing considerations would not be spelt
>out.  So does anyone have such a specification handy?

What you want is a copy of _Beneath Apple DOS_ by Worth and Lechner.
You can buy it from the Byte Works, http://hypermall.com/byteworks/bwad.html
The best $12.95 you'll *ever* spend!

>PS: While I'm here, I'd also like descriptions of what happens with the
>    stepper motors in the drive.

Again, answered (very clearly) in _Beneath Apple DOS_.

Tim. (shoppa@triumf.ca)