[sebhc] Access to the SEBHC archive

Dwight K. Elvey dwight.elvey at amd.com
Wed Sep 1 12:19:52 CDT 2004

Hi Dan
 See my reply to Dave's message. I address issues of
interleaving that you may not be aware of. I don't
think any of your images have issues but it can
be a problem. You'll note that my transfer program
actually has the option to create interleaved disk.
This was done quite often and I know of at least one
disk that I'd gotten from a friend that had this
interleaving done to speed up BASICs load. You
do need to look out for them.
 As you note, none of the realise disk had any form
of interleaving, either track skewing or sector.

>From: "Dan Lanciani" <ddl-cctech at danlan.com>
>"Dwight K. Elvey" <dwight.elvey at amd.com> wrote:
>|Hi Mark
>| It appears to be the same. At most, it might include
>|different interleaving. I expect to look at it tonight
>|to check it out. I don't think the sectors of HDOS were
>|physically interleaved
>They were not interleaved; however, some versions of the driver did
>offset sector 0 on each successive track so that spiral reads did not
>miss a rotation each time.  As with any physical sector manipulation,
>none of this matters to images.  It's only logical interleave (where the
>driver knows a mapping between real sector numbers and those in the
>headers) that causes problems.  As far as I know, this was never done
>on H17-style disks.
>I've now uploaded the three CP/M distributions and my collection of HUG
>disks (some of which probably duplicate what is alread there).
>			Dan Lanciani
>			ddl at danlan.*com
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