Instant Bad Sector w/ no retry

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comradesean
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Instant Bad Sector w/ no retry

Post by comradesean » Thu Apr 30, 2015 11:47 pm

What would cause DTC to skip a track without retrying? It first happened on my Ultima II (1983) program disk on track 40.0 which I chalked up to copy protection, but then it occurred on my Might and Magic III - Disk 3 on track 0.0. The disk then went on to fail on many tracks, but it only attempted track 0.0 once.

SomeGuy
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Re: Instant Bad Sector w/ no retry

Post by SomeGuy » Fri May 01, 2015 2:50 am

If it thinks the track is blank then it does not retry. I've had it do that to me on some marginal damaged disks, and I have to manually try re-reading until it figures out that yes, there is really data here. At least with preservation mode plus guided, I can just re-read the specific track and drop the new version in over the old (usually bad) one and then decode the preservation steam file with the PCE tools instead.

comradesean
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Re: Instant Bad Sector w/ no retry

Post by comradesean » Fri May 01, 2015 4:38 pm

Do you mean when the format can't be detected and it shows up UNK? I've had it halt and reattempt sectors that had no data in them before.

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IFW
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Re: Instant Bad Sector w/ no retry

Post by IFW » Mon May 04, 2015 7:16 pm

If the format is unknown/unformatted there is no point in retrying since it will remain that way - except for some kind of damage/misalignment, as SomeGuy wrote above.

comradesean
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Re: Instant Bad Sector w/ no retry

Post by comradesean » Tue May 05, 2015 1:53 am

IFW wrote:If the format is unknown/unformatted there is no point in retrying since it will remain that way - except for some kind of damage/misalignment, as SomeGuy wrote above.
I'm sorry, I should have been more specific. It was actually reporting it with a big B and not as No Format. But I figured out that it wasn't actually reporting a bad sector, but just a mismatched sector. I think that's why it didn't retry. (This makes sense since that's the copy protected sector for Ultima II)

I'm guessing it was just reading residue or something for the Might and Magic disk.

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IFW
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Re: Instant Bad Sector w/ no retry

Post by IFW » Tue May 05, 2015 10:39 am

Anything that is very likely to be protection is never retried, except for wrong checksums - since the latter is often not protection.

comradesean
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Re: Instant Bad Sector w/ no retry

Post by comradesean » Wed May 06, 2015 2:39 am

An offtopic question, but are frankenstein streams acceptable for preservation? Streams with tracks taken from different drives and or different disks.

hydr0x
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Re: Instant Bad Sector w/ no retry

Post by hydr0x » Wed May 06, 2015 6:37 am

Why not just submit the original, separate streams and let SPS handle the merge?

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mr.vince
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Re: Instant Bad Sector w/ no retry

Post by mr.vince » Wed May 06, 2015 9:19 am

What hydr0x said... :)

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