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Bad rare Atari disk w/errors.


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#1 Allan OFFLINE  

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Posted Sat Mar 18, 2017 7:43 AM

So I won this auction on eBay that had a rare Atari disk. It was suppose to go with an Algebra book for schools. I ran the disk but it never booted. I sector copied it and sure enough it was full of errors. I was able to run at least one of the programs on it. Anybody care to see if they could repair any of the files?

 

Allan

 

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#2 Allan OFFLINE  

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Posted Sat Mar 18, 2017 8:00 AM

Here's the instructions that came with it.

 

Allan

 

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#3 bob1200xl OFFLINE  

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Posted Sat Mar 18, 2017 11:09 AM

Has the oxide been damaged? If the surface of the disk is worn off, not much you can do. If it looks OK, you can usually read it.

 

Bob



#4 AtariGeezer OFFLINE  

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Posted Sat Mar 18, 2017 11:40 AM

Looks like maybe a scratch on the disk?  Sector 11 on a bunch of tracks are empty.  Fixing the Sector Links are pretty easy,  but  filling in Basic Tokens by hand is a bit time consuming :)



#5 ijor OFFLINE  

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Posted Sat Mar 18, 2017 12:23 PM

Assuming the problem is not physical, not oxide coating damage as Bob points out:

 

1 - Give the disk (and the drive) a very good cleanup. There are a few threads here about how to do it.

2 - Make a raw low level dump with something like a SCP or Kryoflux. Sometimes this is enough. Otherwise, post or PM me the raw dump. Sometimes I can recover small magnetic damages.

 

Chances the problem is not the oxide coating, as this usually tends to produce whole track errors, and not one particular sector on several tracks.



#6 ijor OFFLINE  

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Posted Sat Mar 18, 2017 7:50 PM

Chances the problem is not the oxide coating, as this usually tends to produce whole track errors, and not one particular sector on several tracks.

 

I meant: ... and not the same single sector on several tracks.



#7 AtariGeezer OFFLINE  

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Posted Sat Mar 18, 2017 9:25 PM

There are about 38 blank sectors,  12 or so on sector 11 on multiple tracks.  A good 810 with the Archiver Chip works well too...



#8 ijor OFFLINE  

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Posted Sun Mar 19, 2017 6:39 AM

There are about 38 blank sectors,  12 or so on sector 11 on multiple tracks.  A good 810 with the Archiver Chip works well too...

 

What you will achieve with an Archiver in this case???



#9 AtariGeezer OFFLINE  

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Posted Sun Mar 19, 2017 11:41 AM

 

What you will achieve with an Archiver in this case???

I have been able to recover a bunch of my old floppy's that were getting unreliable with the Archiver Software.  I'd first copy the whole disk,  then go back over it on the bad tracks reading one track at a time (with various options),  until it read back a track with all 18 sectors,  then write that track to the Backup Floppy.  If a Sector still had a CRC Error,  I would read the faulty sector using DiSkEy,  then skip ahead or back 10 Sectors,  then back to the faulty one.  This would result in reading a Sector with the Correct Data...


Edited by AtariGeezer, Sun Mar 19, 2017 11:44 AM.


#10 _The Doctor__ OFFLINE  

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Posted Sun Mar 19, 2017 12:22 PM

Geezer is spot on, the only change I used in my procedures was to clean the disk and heads after the first round in the process fails...

 

for whatever reason, microscopic alignment, head settling, crud being pushed a different direction... electronics and or head settling..... the procedure yielded results....

 

The Geezer imparts some old school knowledge again... two thumbs up :)


Edited by _The Doctor__, Sun Mar 19, 2017 12:25 PM.


#11 ijor OFFLINE  

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Posted Sun Mar 19, 2017 1:15 PM

I have been able to recover a bunch of my old floppy's that were getting unreliable with the Archiver Software.  I'd first copy the whole disk,  then go back over it on the bad tracks reading one track at a time (with various options),  until it read back a track with all 18 sectors,  then write that track to the Backup Floppy.  If a Sector still had a CRC Error,  I would read the faulty sector using DiSkEy,  then skip ahead or back 10 Sectors,  then back to the faulty one.  This would result in reading a Sector with the Correct Data...

 

You can do all that with a stock Atari drive, you don't actually need an Archiver, although it might be more convenient. Anyway, that kind of sector retry procedure might help when the disks are, as you call them, unreliable. It is not nearly the same level of recovery that you can do with a raw, flux, low level dump. Some disks are damaged in such a way that you can never read the sector correctly. For instance, in some cases the sector header is completely damaged. With an Archiver or a stock drive, you can't read the data at all. With a low level dump it is rather simple, the data is still there, pristine.

 

Of course, sometimes a simple clean up and retry is all it takes. And sometimes nothing on earth can help.



#12 AtariGeezer OFFLINE  

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Posted Sun Mar 19, 2017 1:45 PM

A stock drive doesn't let you read individual tracks one at a time,  unless you know of a specialized diagnostic software that can send code to the drive to accomplish this???



#13 ijor OFFLINE  

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Posted Sun Mar 19, 2017 3:08 PM

A stock drive doesn't let you read individual tracks one at a time,  unless you know of a specialized diagnostic software that can send code to the drive to accomplish this???

 

But you are not reading a track. You are reading the sectors of a track and you can do that with a stock drive. What I mean is that you are not reading such things as the sector order or timing, or duplicated sectors. You just want the sectors' data.

 

Anyway, my main point is that even with the Archiver, the recovery that you can perform is very limited in comparison to low level tools.
 



#14 AtariGeezer OFFLINE  

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Posted Sun Mar 19, 2017 3:26 PM

But you are not reading a track. You are reading the sectors of a track and you can do that with a stock drive.

I suggest you go back and read my previous post again :) http://atariage.com/...s/#entry3722000

 


What I mean is that you are not reading such things as the sector order or timing, or duplicated sectors. You just want the sectors' data.

No,  I re-read Bad Tracks if not all 18 sectors of a track can be read the first go around.  Then re-read Sectors if they have CRC Errors.

 


Anyway, my main point is that even with the Archiver, the recovery that you can perform is very limited in comparison to low level tools.

You do things your way,  and I'll do it "Old School",  because it does indeed work  :)



#15 Bryan OFFLINE  

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Posted Sun Mar 19, 2017 4:16 PM

Also, a disk may still be readable, but the lubricating coating may have deteriorated to where the disk drags or 'whines'. Reducing the force on the pressure pad may help you get a good read.



#16 Allan OFFLINE  

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Posted Sun Mar 19, 2017 7:51 PM

Has the oxide been damaged? If the surface of the disk is worn off, not much you can do. If it looks OK, you can usually read it.

 

Bob

I don't think so.

 

Allan



#17 Allan OFFLINE  

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Posted Sun Mar 19, 2017 7:53 PM

Assuming the problem is not physical, not oxide coating damage as Bob points out:

 

1 - Give the disk (and the drive) a very good cleanup. There are a few threads here about how to do it.

2 - Make a raw low level dump with something like a SCP or Kryoflux. Sometimes this is enough. Otherwise, post or PM me the raw dump. Sometimes I can recover small magnetic damages.

 

Chances the problem is not the oxide coating, as this usually tends to produce whole track errors, and not one particular sector on several tracks.

I can do number one but I don't have a SCP or Kryoflux. I'll try cleaning it and see if that helps.

 

Allan



#18 Allan OFFLINE  

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Posted Sun Mar 19, 2017 7:55 PM

Thanks guys for all your input. I'll try cleaning the disk to see if that helps.

 

Allan



#19 ijor OFFLINE  

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Posted Mon Mar 20, 2017 9:48 AM

I suggest you go back and read my previous post again :) http://atariage.com/...s/#entry3722000
No,  I re-read Bad Tracks if not all 18 sectors of a track can be read the first go around.  Then re-read Sectors if they have CRC Errors.

I realize you are reading tracks. But unless the disk is copy protected it makes no different at all. You would get the same net effect if you would read individual sectors. What you are doing is just performing some variations on how you retry reading the sectors, because that's what the Archiver does when you read a track. You don't use any of the low level track data (again, sector order, timing, etc).
 

You do things your way,  and I'll do it "Old School",  because it does indeed work  :)


Of course it works, I didn't say it doesn't. Any reasonable retry and recovery strategy will work in some cases. Just that some methods will work in more cases than other ones.



#20 ijor OFFLINE  

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Posted Mon Mar 20, 2017 9:51 AM

I can do number one but I don't have a SCP or Kryoflux. I'll try cleaning it and see if that helps.

 

If cleaning and other methods fail, and if the title is indeed very rare, then may be you should contact somebody that can do a low level dump or perform a different recovery strategy.



#21 _The Doctor__ OFFLINE  

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Posted Mon Mar 20, 2017 11:08 AM

I think the disks should be left as is and taken or transported to someone who has had experience cleaning and Kryo /super card capable.... this will ensure further loss does not occur!

 

Once you have learned the ropes by watching either directly or remotely (youtube of it maybe) practice with screwed up disks that are a dime a dozen and don't matter because you already have everything elsewhere...    just saying to be careful...  having been told some horror stories and received disk that were destroyed by little or no experience... just trying what they can... good intention-ed persons...  some times when the oxide is going you can clean too much.. best to go slow and leave just enough behind.... the pattern while degraded may still be there..... looking at the degraded stream and picking the prevalent number or numbers or trying each until something use-able is produced... some peeps have algorithms they run to automate such attempts  but not me...

 

In any event that's my thoughts......


Edited by _The Doctor__, Mon Mar 20, 2017 11:10 AM.


#22 bob1200xl OFFLINE  

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Posted Mon Mar 20, 2017 11:49 AM

OK... disk errors:

 

Oxide scraped off the surface. You can see wear on the disk oxide. Depending on how much oxide is gone, the data may have gone with it. Be very careful if you see oxide damage. Oxide will build up on the head and then wipe out the next disk you read.

 

End-of-life or contaminated disk jacket. This will impede disk rotation, causing random errors. You may have to cut open your disk and move the platter to another, good sleeve. You may need to clean mildew/mold off the disk with dishwashing soap and a soft cloth.

 

Disk written off-speed or off-track. These will normally be repeatable errors. I keep a 1050 that is used to read these kinds of disks by tweaking the servo and speed control until I get a good read.

 

If the disk was readable at one time, you can usually read it again - if the oxide is OK.

 

I don't know where my 'fixer' 1050 is, but I can maybe read your disk for you. PM me.

 

Bob






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