Hard sector format

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Jeff
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Re: Hard sector format

Post by Jeff » Thu Aug 01, 2019 5:49 pm

exidyboy wrote:
Thu Aug 01, 2019 5:25 pm
HxC appears to be interpreting the geometry although the data itself is unsurprisingly not correct.

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According to your picture you have not imported the raw file correctly.

To read your kryoflux dump, drag and drop one of the kf .raw files on the main window. The importation processing time can be long, be patient... ;)

exidyboy
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Re: Hard sector format

Post by exidyboy » Thu Aug 01, 2019 7:05 pm

Jeff wrote:
Thu Aug 01, 2019 5:49 pm
To read your kryoflux dump, drag and drop one of the kf .raw files on the main window. The importation processing time can be long, be patient... ;)
Yes you are quite right :(
Nothing but a sea of red now.
Thanks for taking a look though Jeff.
Image

Jeff
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Re: Hard sector format

Post by Jeff » Thu Aug 01, 2019 7:22 pm

exidyboy wrote:
Thu Aug 01, 2019 7:05 pm
Nothing but a sea of red now.

Not exactly : I see the odd or even tracks without red. This probably means that the disk have large tracks. place an empty file named "doublestep" in the raw files folder and reload the raw. The software will skip the inter-tracks "tracks".

Once done don't hesitate to enable more decoders : FM,MFM, HEATHKIT, Northstar...
It is possible that the software can't decode these tracks if this machine use an "alien" sector encoding, but at least you see if the disk dump appears "clean" in the track viewer.

Also please some post track view mode screens (one odd & one even track). These are quite usefull to figure out what is going on.

exidyboy
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Re: Hard sector format

Post by exidyboy » Fri Aug 02, 2019 3:31 am

Jeff wrote:
Thu Aug 01, 2019 7:22 pm

Not exactly : I see the odd or even tracks without red. This probably means that the disk have large tracks. place an empty file named "doublestep" in the raw files folder and reload the raw. The software will skip the inter-tracks "tracks".
If by large tracks you mean written by a 40 track drive then yes this is my assumption.
WIth the doublestep file (no extension) the results look very good.
Jeff wrote:
Thu Aug 01, 2019 7:22 pm
Once done don't hesitate to enable more decoders : FM,MFM, HEATHKIT, Northstar...
I tried all those but the results don't look any different.
Jeff wrote:
Thu Aug 01, 2019 7:22 pm
It is possible that the software can't decode these tracks if this machine use an "alien" sector encoding, but at least you see if the disk dump appears "clean" in the track viewer.
The controller is pure TTL so probably will not correspond with any of the profiles you have currently implemented but hopefully is close.
Jeff wrote:
Thu Aug 01, 2019 7:22 pm
Also please some post track view mode screens (one odd & one even track). These are quite usefull to figure out what is going on.
Presumably you want the odd and evens before the double-stepping is applied?

Image

Jeff
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Re: Hard sector format

Post by Jeff » Fri Aug 02, 2019 10:58 am

The dump appears good to me. The red lines are the sector write splices.

Please :

- Show me a track in track viewer mode.
- Enable all decoders available (you can enable all in the same time).

exidyboy
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Re: Hard sector format

Post by exidyboy » Fri Aug 02, 2019 2:28 pm

Selected tracks from 3 different discs:

Disk 33 Track 0 Side 0

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Disk 33 Track 0 Side 1
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Disk 37 Track 20 Side 0
Image

Disk 37 Track 20 Side 1
Image

Disk 49 Track 34 Side 0
Image

Disk 49 Track 34 Side 1
Image

exidyboy
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Re: Hard sector format

Post by exidyboy » Sat Aug 03, 2019 8:32 am

Jeff wrote:
Thu Aug 01, 2019 7:22 pm
Once done don't hesitate to enable more decoders : FM,MFM, HEATHKIT, Northstar...
Here is an interesting snippet from a 1985 Sorcerer newsletter.

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Re: Hard sector format

Post by Jeff » Sat Aug 03, 2019 9:27 am

Yes interesting. So the format is supposed to be close enough to the northstar format. is there some technicals informations about the sector format somewhere ?

exidyboy
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Re: Hard sector format

Post by exidyboy » Sat Aug 03, 2019 2:56 pm

I have not been able to find any documentation yet although Dutchacorn (from earlier in this thread) had some timing diagram screen shots - but you guys were saying the timing couldn't have been correct for 10 sector ...

I take the excerpt from the newsletter article to mean that a CP/M system with a Northstar controller could read a Vista format disc if appropriate changed were made in the CP/M software.

Edit:
I believe the discs would have been written with an MPI B51 40 track drive single-sided drive.
205K formatted.
I realise that doesn't help you with the sector though.

exidyboy
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Re: Hard sector format

Post by exidyboy » Tue Aug 06, 2019 1:11 am

Progress has been made on the sector format and preamble.
Focus is now on the checksum algorithm.

exidyboy
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Re: Hard sector format

Post by exidyboy » Thu Aug 29, 2019 5:45 am

All the Vista hard sector discs for the Exidy Sorcerer have now been imaged and individual files extracted.

Thanks to Kryoflux for their work to add support for the hard sector format to their technology stack and for input into the format.

Thanks to Simon Owen for investigating a lot of time reverse engineering the Vista format and processing the Kryoflux preservation streams into raw images. The next release of Samdisk will support this Vista hard sector format.

Various contributors on VCFED has taken Simon's .raw files and extracted files using cpmtools/libdisk.

Technical documentation for the Vista system is still MIA but page 114 of the Sorcerer's Apprentice newsletter Vol 4 No. 6 (September 1982) contains some engineering details attesting to the rumoured proximity of the Northstar and Vista formats.
I'm sure those details would have helped Simon if they had come to light at the time.

The details might also assist in evaluating the feasibility of supporting hard sector disks in HxC on either current or future hardware.
See page 114-116 of http://www.bitsavers.org/pdf/exidy/Sorc ... ep1982.pdf
and source code of the conversion utility from page 126.

Thanks of course to Jeff and the contributors on this forum.

A great international team effort.

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