Preserving Atari 8-bit disks

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fgasking
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Joined: Thu Mar 26, 2015 10:36 pm

Preserving Atari 8-bit disks

Post by fgasking » Sun Mar 29, 2015 6:31 pm

Hi all,

Most of my work involves the Games That Weren't project at http://www.gamesthatwerent.com/gtw64 - and recently I have obtained some Atari formatted 5.25" disks from a coder who used an Atari 600XL and 1050 drive to develop C64 games (and port down a serial cable to a C64 to compile and test). They seem to be single sided double density disks that have been recorded on, and only recorded on one side (notched on only one side).

I brought a Kyroflux recently, and have been trying to use a IBM YD-580 320/360kb 5.25" drive to preserve the disks - but sadly i'm not having much luck at all. I assume that it is the 3a (FM XFD) format that I need to use to preserve them - but i'm either getting bad sectors or unformatted on any Atari disk that I try (even original software). I've tried cleaning the disks and the drive heads, but with no further joy.
Trying a C64 format disk will recognise the format, but with many bad sectors and errors - producing a D64 which is completely corrupted (and even using a fully working disk). Same C64 disk managed to back up perfectly fine using my 1541 Ultimate.

Interestingly the drive has managed to read some PC formatted disks with the Kyroflux without any problems though, recognising the DOS format and backing them up as IMG files.

I'll be honest, i'm no expert on disk drives at all - and from what I can gather online, a 41 track drive should be fine to read the disks and the jumpers are set up correctly. I'm just wondering if there is something i'm missing or if I need to modify on the drive to help things along, or if maybe I just need a different drive?

Any help or suggestions would be really great, and I can provide a RAW copy of one of the disks if required.

Feltzkrone
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Re: Preserving Atari 8-bit disks

Post by Feltzkrone » Sun Mar 29, 2015 7:50 pm

Could you upload RAW files for one of the disks at a one-click hoster? We could take a look then. Please do also include the command line used to dump and a log file if possible (see viewtopic.php?f=3&t=458&p=4280&hilit=tee#p4280 if you're using Windows and want to print progress to console and simultaneously to log file).

fgasking
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Joined: Thu Mar 26, 2015 10:36 pm

Re: Preserving Atari 8-bit disks

Post by fgasking » Mon Mar 30, 2015 1:44 pm

Thanks Feltzkrone - i'll get this sorted tonight.

fgasking
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Re: Preserving Atari 8-bit disks

Post by fgasking » Mon Mar 30, 2015 9:32 pm

Here we go:

http://www.gtw64.co.uk/dumps/roaddump.zip (raw files)
http://www.gtw64.co.uk/dumps/roaddump.log

Command used to produce the above was:

dtc -froaddump -i0 2>&1 | wtee roaddump.log

If you need anything else, let me know and many thanks!

Feltzkrone
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Re: Preserving Atari 8-bit disks

Post by Feltzkrone » Tue Mar 31, 2015 11:38 pm

I'm almost sure that it's a problem with the drive. To be more precise: With the alignment of the drive.

To me it looks like data of adjacent tracks is bleeding into each other in particular areas. A small percentage of sectors are still intact in the dump but taking into account that you have also tried without success using a C64 disk which worked fine with a different drive I'd suggest using a different 5.25" drive with KF. It doesn't have to be a 360 KB drive, a more common 1.2 MB HD drive will also do.

Judging from the log you didn't restrict the number of tracks to 41 which possibly has caused the drive to bump the head in the middle of the dumping process. Depending on the drive mechanics this could have lead to the misalignment (in case you have dumped other disks the same way before that one). DTC defaults to 84 tracks. With each new drive you should do a calibration first using the -c2 command.

So when using 41 track (= 48 tpi) drives (calibration would e.g. show maxtrack: 40, counting from 0) please make sure that you use command -e40 at the end of your command line, e.g.
dtc -froaddump -i0 -e40

As said before you can also go for 96 tpi / 1.2 MB / HD drives. Most of us are using these for dumping C64 disks. And in case you haven't read about it yet: If you are intending to also fully dump back sides of flippy disks (such as C64 disks which one could also insert upside down / flipped into the drive) you will need a modified drive which allows the head to be positioned at track -8: Either do the modification yourself, let someone else do or buy a pre-modded drive.

I hope that this information is helpful to you and if you need more details on particular topics please don't hesitate to ask. Most of the topics/problems addressed here are already covered in different threads, so by searching the forums you should also be able to get access to useful additional information. :)

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Mayhem
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Re: Preserving Atari 8-bit disks

Post by Mayhem » Wed Apr 01, 2015 3:09 pm

If you're having problems Frank, and need these doing soon-ish, you could always send them to me. I've got a full Kryo setup here with modified drive. I'd just need the proper and full command line to type ;)
Lie with passion and be forever damned...

fgasking
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Re: Preserving Atari 8-bit disks

Post by fgasking » Wed Apr 01, 2015 11:20 pm

Thanks Feltzkrone for taking a look and all of the advice given. I really appreciate it!

Unfortunately the successful C64 disk port was with a 1541-II drive and a 1541 Ultimate 2. I do have another PC drive (A TEAC FD-55GFR 1.2mb drive) - but after many attempts, cleans and reading the documentation on it, I couldn't get past the dredded "No disk in drive" message for many disks (suggesting that has a fault too).

I think i'll look out for another 1.2mb drive as suggested, and then have a go at the flippy mod (which I will need longer term). Long term I would like to get a solution to help dump other formats like this as part of the project. The waiting list for a refurbed drive seems pretty long, so i'll just have to keep an eye on Ebay.

@Mayhem - That is very kind of you if you would be up for that in the short term for now? I assume that your modded drive would be equipped to handle Atari 8-bit disks? I wouldn't know the exact command to use though - but I can point towards the commands i've tried using on the Atari Age forums to give a try?

Thanks for your help guys! :)

fgasking
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Joined: Thu Mar 26, 2015 10:36 pm

Re: Preserving Atari 8-bit disks

Post by fgasking » Thu Apr 02, 2015 9:01 pm

Another quick question, but Mayhem has very kindly offered to have a go at porting the disks with his modified (and working) drive.

Which would be the best command line parameters to use for such disks?

I had found and used the following:
dtc -fdiskname -g0 -k1 -e41 -i0 -fdiskname-raw -g0 -k1 -e41 -i2 -fdiskname.xfd -g0 -k1 -e39 -i4a

Does this seem correct?

Just in case the -i4a option wasn't working, I did try using a8rawconv (http://atariage.com/forums/topic/231835 ... n-utility/) to convert the RAW files to an ATX file, with no joy due to the files produced not being great.

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IFW
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Re: Preserving Atari 8-bit disks

Post by IFW » Fri Apr 03, 2015 8:07 pm

Imho wait for a proper modded and aligned drive...
Not sure what you are trying to do with that command, but you can dump any disk to stream with just a blind dump:
dtc -fname -i0
and then add formats to check against, ,e.g. -i6 for CBM DOS and where the *original* system is not supposed to use both sides of a disk (e.g. CBM) you want to add side control before the format e.g. -g2 -i6. Since CBM is a flippy format add -y; -y -g2 -i6.
Usually you don't want to see most of the output, just the format check, which you can achieve by adding -l8
Also add some decent amount of retry -t10 is enough in most cases, you probably need to clean the disk if it's supposedly readable and 10 retries are not enough.
There is physical offset of 8 tracks between the 2 heads of a flippy modded drive. With the most common modification you need to add -b-8.
You'd probably also prefer to have folders generated for you automatically - just add -p
So something like this would work for a CBM DOS disk:
dtc -p -b-8 -fstreamname -i0 -y -g2 -i6 -l8 -t10

For an A8 disk, it depends on what kind of disk it is; could be FM or MFM, flippy or double sided - so you need to find out first.
A blind dump can do that for you and let's you experiment with the parameters later:
dtc -fstreamname -i0
Then you could access the stream files by adding -m1
dtc -m1 -fstreamname -i0 and experiment with the formats and parameters - the disk will no longer be accessed, just the stream files.
Alternatively, post the first few tracks (first 10 at most from both sides should be enough) and someone can take a look ;)

An FM flippy disk is likely to work with this:
dtc -p -b-8 -fstreamname -i0 -y -g2 -i3a -l8 -t10
3a is default parameters for A8 FM - these are always flippy disks.

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IFW
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Re: Preserving Atari 8-bit disks

Post by IFW » Fri Apr 03, 2015 8:10 pm

Forgot... you often need to control the density line, just add -dd0 or -dd1.
Unfortunately, it's impossible to tell which one since it depends on the drive type, jumpers/hardwired settings etc.

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