On Sun, 31 Oct 2021, Chuck Guzis via cctalk wrote:
On 10/31/21 9:57 AM, geneb via cctalk wrote:
I'm working with the developer of the Applesauce disk imaging tool in
order to iron out some issues with 8" disk support.
I'm using a Qumetrak 842 disk drive that's got support for both double
and single-sided media. This means that it's equipped with two index
hole sensors, slightly offset from one another. It's my understanding
that single-sided media has the index hole in one spot on the jacket,
and double-sided media has one in a slightly different location.
The issue at hand is some NIB Dysan double-sided 8" media I have - the
disks have index holes in the jacket in both locations. Is this
typical, or do I have some weird "special" disks on my hands? The
Applesauce author posits that the combination of the dual-sensor drive
and the dual-hole media wouldn't typically find themselves together. Is
this accurate? If it's not, how would a system contemporary with the
media have handled the two index holes?
Gene, are you certain that these aren't "flippy disks" (two index
apertures)?
Chuck, here's a photo of the disk type I'm using:
https://i.imgur.com/Cq778xT.jpg
As you can see, they're not mirrored for "flippy" use.
But I've seen what you describe.
I recall one occasion where I received the single-double type that you
describe and having to cover the single-sided hole to get to the other
side of the disk.
If I have to mask off one of the index holes I can do that. I can
understand why Dysan would produce a disk that could be used in either
drive, but a drive that could use both single and double-sided media had
to have been common back then, which leaves me wondering how it was
handled.
tnx!
g.
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