more weirdities (Was: Tandon TM 100 5 1/4" drives

From: Don Maslin <donm_at_cts.com>
Date: Tue Oct 19 21:56:36 1999

On Tue, 19 Oct 1999, Fred Cisin (XenoSoft) wrote:

> On Tue, 19 Oct 1999, Don Maslin wrote:
> > But let's muddy the conversational waters a bit :) I have no quarrel
> > with describing a 360k DOS disk as 40 cylinders, but let's consider a
> > disk such as the Xerox 820-II 5.25" DSDD. Unlike the DOS disk, the
> > Xerox does not read side 0 first and then continue on to side 1.
> > Instead, it reads track 0 side 0 and then goes on to read track 1
> > side 0. Is not it reasonable - perhaps more reasonable - to call the
> > Xerox disk an 80 track disk? Or better, an 80 track 48 tpi disk.
>
> In addition to disk formats that use all of the sectors of one track, and
> then use all of the sectors of the same cylinder's track on the other
> side, and then advance to the next cylinder:
>
> Some formats (particularly ones that were once single sided, and then
> expanded into DS formats) use all of one side and then use all of the
> second side starting over at cylinder 0 of the second side.
>
> Some start over at a later cylinder of the second side (so that the same
> number of tracks are "Reserved/skipped" on both sides).
>
> Some use all of the first side and then use the second side counting DOWN.
> Thus, after Side 0 Cylinder 38, then side 0 cylinde 39, then Side 1
> cylinder 39, then side 1 cylinder 38, . . .
> That eliminates having to do a seek back to track^H^H^H^H^H cylinder 0.
>
> Some that use various logical sector skewing will treat the entire
> cylinder as a track, thus using one or more sectors from one side followed
> by one or more sectors from the other side, back and forth.
>
>
> And then, there are some that are WEIRD.

Nah! Really?

                                                 - don
 
> --
> Grumpy Ol' Fred cisin_at_xenosoft.com
>
>
Received on Tue Oct 19 1999 - 21:56:36 BST