Grrr - !%#*^@# Kaypro!

Dwight K. Elvey dwight.elvey at
Wed Aug 3 17:20:47 CDT 2005

>From: "Dwight K. Elvey" <dwight.elvey at>
>>From: "Fred Cisin" <cisin at>
>>On Wed, 3 Aug 2005, Dave Dunfield wrote:
>>> Tried ImageDisk on some Kaypro disks this morning...
>>> Buggers recorded side1 as additional sectors of side0.
>>> The different set of sector numbers didn't bother
>>> ImageDisk, but it had a bit of a tantrum with the Head
>>> ids which didn't match the physical head selection.
>>Quite common :-(
>>765 insists on accurate sector headers;
>>WD 179x can ignore the head # field in the sector headers.
>>The Kaypro won't even mind reading/writing a disk,
>>if you FORMAT it with a 765 using valid sector headers!
>>> I can imagine that someone somewhere does weird things
>>> with the Cylinder ids on a track as well ...
>>Rare.  I've only seen it a few times.
> At least for Dave's setup, he could get by with
>a bypass switch on the head selector. It is always
>funny what different setups have done. At least there
>is a potential bypass for this one.
> I'd guess the fellow that wrote the driver for the
>Kaypro didn't have a problem so he didn't notice the
>missing head information in the sector header. He
>may have thought the controller took care of this
>somehow. I know when I've fiddled with the disk controller
>directly, it isn't always clear when and where
>each register takes effect. There are a few places
>that it seem that there is redundant information.
 I see from Dave's post that this was one of those redundant
information I was talking about. I wonder if all the
later PC controllers deal with these fields the same?

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