Checking for and Retrying Bad Sectors while using Stream Files (Preservation)

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horse_dreams
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Joined: Wed Jan 16, 2019 8:10 am

Checking for and Retrying Bad Sectors while using Stream Files (Preservation)

Post by horse_dreams » Wed Mar 06, 2019 8:08 am

So I've got this gigantic stack of 3.5" floppy disks I want to image with my KryoFlux, 99% of them being Macintosh formatted. I've already asked some questions here and this post by SomeGuy got me thinking:
SomeGuy wrote:
Fri Mar 01, 2019 11:01 pm
Preservation stream dumps keep 5 revolutions of data. If it did not get a good read for a sector it will always show bad. I might be mis-remembering but I think format guided only store one revolution - but with Macintosh disk you really need to keep all five revolutons. But format guided does retry and will keep only successfull reads unless the it exceeds the maximum retries.
What I am wondering is, is there a way that I can save a disk as "KryoFlux stream files, preservation", while also checking for bad sectors along the way? Kind of like a hybrid between (in my case) "Apple DOS 400K/800K sector image" and the stream files, where it not only checks for and retries bad sectors until it either gives up or reads it successfully, but also saving every revolution of data like SomeGuy noted.

I saw "KryoFlux stream files, format guided" in the list, but checking the default settings in the GUI for this option, as well as checking the manual, showed me that it, 1) saves the disk as .img, NOT .raw, and 2) uses the -i0a flag with `dtc`, which the manual noted as a no-no for preservation.

Also, this is probably a dumb question, but does setting the revolutions in the GUI to a higher number than the default, i.e. 20, make the resulting .raw files much larger?

I'm using v3.00 of the KryoFlux GUI under Windows 7 (32-bit).

SomeGuy
Posts: 242
Joined: Wed Feb 18, 2015 8:18 pm

Re: Checking for and Retrying Bad Sectors while using Stream Files (Preservation)

Post by SomeGuy » Wed Mar 06, 2019 8:05 pm

Taking a closer look, it is possible to specify the number of revolutions. That will make "KryoFlux stream files, format guided" save whatever number you specify. Yes, more revolutions means larger RAW files. Specifying more than 5 has little value.

Since I often deal with unknown formatted, copy protected, and decaying disks, my workflow is usually just to start with a Preservation dump, feed that back in the GUI and other tools for decoding/analysis and then manually redump individual tracks or the entire disk if retrying is needed. Admittedly that is "the hard way" and can be a pain. If you know these are all supposed to be Mac 800k/400k disks, then guided will probably work better for you.

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