Strange Request

[customukr]

Hi,

One of our clients wishes to obtain an old JPG of his sons football team from an old redundant floppy drive.

There are two in total, one with a pzp archive (with the jpg embedded), the other one has the single jpg file.

Both the floppy drives have bad sectors, therefore attempting to copy out of the drive onto desktop will fail with both. The drives and files can be loaded into HxD, but as you scroll down the data stream it will lock up. Of course tools like R-Studio etc can't get around the bad sector issue.

I need to clone the device, but have a lack of available tools (apart from DD). What do you think will be sufficient? I don't want to try DD until I know the best course of action as i'm worried the amount of stress the device will receive will leave it unusable.

I appreciate your time.

Thanks,

Chris

[Spildit]

What are the type of the floppy disks ? Do the client have the original computer/drive used to write the floppy ?
By norm very old computers floppy drives tend to handle better floppy then the recent drives.
Sometimes a drive will not read sectors on a floppy when other drive will read just fine.
Check the inside of the disk for moisture/mould too, as it can prevent reading and get the heads of the reader dirty.
If you have a very old pc, like a IBM Ps2 you will have better resoults reading damaged floppies at the low speed it uses.
Clean the reader heads with absolute alcool.
I have some Ms-dos 4.0 disk cloning tools that work on those old systems and are ideal to clone the floppy, but if the floppy is clean from mould and was not stored near something magnetic most of the time you just need an older computer/drive. Using the same drive that was used for recording is also a good trick .
If you want to outsource the job i think i can handle it without problem, as i've recovered thousands of floppy and video tapes with mould inside with great rate of success.

[hhddrec]

Good advice Spildit

Hi customukr.

You must clone tools, if you do not know this tools contact with a pro.

[Spildit]

Hi,

One of our clients wishes to obtain an old JPG of his sons football team from an old redundant floppy drive.

There are two in total, one with a pzp archive (with the jpg embedded), the other one has the single jpg file.

Both the floppy drives have bad sectors, therefore attempting to copy out of the drive onto desktop will fail with both. The drives and files can be loaded into HxD, but as you scroll down the data stream it will lock up. Of course tools like R-Studio etc can't get around the bad sector issue.

I need to clone the device, but have a lack of available tools (apart from DD). What do you think will be sufficient? I don't want to try DD until I know the best course of action as i'm worried the amount of stress the device will receive will leave it unusable.

I appreciate your time.

Thanks,

Chris

Ok. I'm assuming you work at a data recovery firm.

First i would check the interior of the floppy for mould. If there is mould on the disk it will contamine the head on the drive and will not read and will cause scratches on the floppy disk.

Then i would use one of those :



Those computers read floppy at a very slow speed and are very tolerant to error on the surface of the floppy.
Also, those floppy readers ignor the little window on the floppy that sets High Sensity. So you can read Lower density formated as high density without having to puntch a hole on the corner of the floppy.
Use DOS 4.0 and image the floppy. Then with the disk editor extract the file.

If the 2 floppy that you have contain the SAME copy of the file, even better, as you can use parts of the file retrieved from the compressed pzp (you have to force sector by sector decompression) to fill the bad spots on the other file.

At any rate remember that floppy drives have some diferences from ones to the others, and writting on the floppy using one machine might mean writting to the floppy track in a slight diferent position that another floppy drive would write/read too. Agan, PS1 computers are very, very, very tolerant regarding floppy and i was able to copy more then 1000 of those that wouldn't even read on a regular present day usb floppy reader.

If you want to outsource those disks to me you will not risk a thing. If you get stuck during your work and can't go any further you can image whatever you can and if you don't have luck (AS LONG AS YOU DON'T DAMAGE THE FLOPPY EVEN FURTHER) you can just ship those floppies to me and i will send the files back to you by mail, and the cost is very low, same as for the risk as you will have a image of the max. that you can clone using your tools

I'm very confident that as long as it's recoverable i will be able to do it, as i started my hobby on DR on school days when students were starting to use floppies (on that time it was like a rarity to find people with computers/floppies) and i've allways had a great recovery rate on those, even when most of the computer shops at the time would fail.

Best regards. Wishing you luck for the project.

[fzabkar]

If you have a very old pc, like a IBM Ps2 you will have better resoults reading damaged floppies at the low speed it uses.

Your statement made me curious, but I was unable to find any reference to any speed other than 300RPM or 360RPM. In fact, AISI, a reduced rotation rate would result in a lower signal amplitude. That's because the EMF induced in the head coil is proportional to the time rate of change of flux, and that is in turn proportional to the RPM. Therefore ISTM that reducing the RPM would make it more difficult to read a marginal diskette.

[Vorian]

But it is true that usb floppy disk drive are *very* sensitive and give lots of errors when reading old floppies

[dick]

It might also help to use one of the old floppy copying utilities in pure MS dos. So copy from source to target floppy.

For example I used to use a little copying utility called 'exact diskcopy' well I think that was what it was called. This was very useful for making identical copies of floppy disks with sectors outside the usual parameters and would also copy any bad sectors. That way we were able to back up copy protected disks for the old Atari games consols and the like.

Do you have old floppy disk drives to test if they are working? As has been mentioned over time the disks and drives seem to go slightly out of specification which means there might be an element of luck riding on this. Sorry to say!

[Spildit]

Hi,

One of our clients wishes to obtain an old JPG of his sons football team from an old redundant floppy drive.

There are two in total, one with a pzp archive (with the jpg embedded), the other one has the single jpg file.

Both the floppy drives have bad sectors, therefore attempting to copy out of the drive onto desktop will fail with both. The drives and files can be loaded into HxD, but as you scroll down the data stream it will lock up. Of course tools like R-Studio etc can't get around the bad sector issue.

I need to clone the device, but have a lack of available tools (apart from DD). What do you think will be sufficient? I don't want to try DD until I know the best course of action as i'm worried the amount of stress the device will receive will leave it unusable.

I appreciate your time.

Thanks,

Chris

Well, i'm assuming it's a 3 1/2 disk and not an 5 1/4 (i support those too and can recover from those too).
At any rate if you placed the disk on a "recent" drive and didn't bother to slide the metalic "window" of the floppy to peek at the disk, i bet that by now you will have some very beautifull circular marks/scratches all over some of the tracks.

I've spend a considerable part of my teenager days recovering those disks (and VHS tapes).

The best piece of advice to give is :

1 - Open the slide metalic window of the floppy and peek inside. If there is dust and Mold DON'T try to read it that way. Disk have to be cleaned in a "special way" with "special product" and forget about water with soap as people say on the net. It will not work and cause mor damage.

2 - Get a very old drive, the older you get the better as long as it working. Clean the heads with absolute alcool. Let it dry. If you can grab an old computer the better. Forget about USB floppy drives or even internal recent ones, they are "crap". Maybe because of the "quality" of the older drives, they will read even when recent drive will not.

3 - Boot under DOS and NEVER windows, not EVEN 3.1.

4 - Use "Exact Diskcopy" (PC (Floppy) Utilities) or Norton DE, or if you have PS1 boot from ROM and use the IBM DOS (copy disk) option or under PS1 try to copy the file to HDD even without cloning.

5 - If you don't get luck try another drive / reader and be sure that the heads on the reader are clean. Also make sure that you didn't cause more damage to the floppy by peeking inside the disk and rotating the disk wile opening the slider window.


In most of cases this will get the job done if the floppy isn't too damaged (like the mold eat the disk or the heads punched a hole to one side to the other of the floppy).

[Spildit]

Your statement made me curious, but I was unable to find any reference to any speed other than 300RPM or 360RPM. In fact, AISI, a reduced rotation rate would result in a lower signal amplitude. That's because the EMF induced in the head coil is proportional to the time rate of change of flux, and that is in turn proportional to the RPM. Therefore ISTM that reducing the RPM would make it more difficult to read a marginal diskette.

In the data recovery world, as with many things in life, one thing is what you learn from school and from books, and another is what happens in real life with practice day after day.
The point is, a IBM PS1 is way slower to copy the data, i don't know if it's the drive that is spinning slower or if the data is slower to transfer, or whatever, maybe it's the drive that have a better quality that recent drives don't have, maybe this, maybe that .... the fact is that with those old computers working in DOS 4.0 with DOS apps i'm able to recover floppy disks that people with recent computers can't even read.
Best regards.

[Spildit]

This topic brings back old memories ....

I've googled a little bit.

Interesting reading about how to recover data here :

http://www.nypl.org/blog/2012/07/23/dig ... al-history

If you have a very old pc, like a IBM Ps2 you will have better resoults reading damaged floppies at the low speed it uses.

Your statement made me curious, but I was unable to find any reference to any speed other than 300RPM or 360RPM. In fact, AISI, a reduced rotation rate would result in a lower signal amplitude. That's because the EMF induced in the head coil is proportional to the time rate of change of flux, and that is in turn proportional to the RPM. Therefore ISTM that reducing the RPM would make it more difficult to read a marginal diskette.

It might not be a question of speed after all, but the controller.
On modern computers if you use a good controller like the KryoFlux you will be able to read data on floppy disks that you can't with other controllers.

http://webstore.kryoflux.com/catalog/index.php?cPath=1

As I mentioned in my post about how to use the FC5025 ( http://www.spellboundblog.com/2011/07/2 ... sks-from... ), I found many of my disks had read errors on some sectors. Is there a chance that the KryoFlux will be able to read sectors that the FC5025 cannot?

Thanks!
Jeanne

Jeanne

Yes, it is possible. The Kryoflux operates at a lower level than FC5025. You can set the KF to attempt to read a sector it cannot reads as many times as you like. In the Manuscripts Division @ NYPL our KF is set to attempt twenty reads on each sector before throwing in the towel. Often the KF will read a sector 10+ times then somewhat magically get a good read.

While I haven't gone back and re-imaged any 5.25 disks done on the fc5025, it's in the plan for the collection of floppies we are currently working on.

Don Mennerich

Guess that my IBM PS/1 Controller and drive are as good as the Kryoflux lolololol

And by the way, if the floppy that you are trying to read is a low density one (only one window to write-protect and no window on the other side of the floppy) modern USB floppy drives will not even read those !!!! (The majority will only read HD floppy)

[fzabkar]

@Spildit, I don't for one second question your data recovery experience with floppy diskettes. However, I do take issue with your explanation, and I do that as an electrical engineer. I also have some practical hands-on experience with the PS/2 Model 25 (720KB 3.5" FDD) and the PS1. I did once have the complete set of IBM's technical reference manuals for the Model 25, but I can't recall any specification data for its FDD. However, I do still have the IBM PC/AT Technical Reference Manual.

In fact here are the schematics for the original IBM PC/AT HDD/FDD MFM controller:
http://www.users.on.net/~fzabkar/PC-AT/FDC_HDC/

AISI factors that could explain the PS1's slow FDD copy speed would be track-to-track skew and head skew. In the ideal case the maximum copy time at 300 RPM would be ...

80 tracks per side x 2 sides per diskette x 0.2 seconds per revolution = 32 seconds

The IBM PC/AT standard allows for programmable head load/unload times and stepping rates, among other things. If PC DOS or OS/2 were to opt for more conservative values for each of these parameters than does MS-DOS or Windows, then it could result in the target sector passing by the head before it settles on the next track, which in turn would necessitate an additional revolution. This would significantly increase the copy time.

In fact I once played with a DOS utility that enabled the user to tune these FDD settings, including skew.

http://www.qnx.com/developers/docs/qnx_ ... ormat.html

As for RPM, AFAICT the 720KB and 1.44MB 3.5" drives both spun at 300RPM just like regular PC drives.

See http://retrotechnology.com/herbs_stuff/drive.html

The early 1.2MB 5.25" drives were dual speed (360RPM and 300RPM), but the latest ones were 360RPM single speed drives.

The data separator on the PC/AT FDD controller could be configured for 250kbps, 300kbps, or 500kbps data rates. If you were to slow the drive down, then the data separator's PLL wouldn't have enough range to lock onto the bitrate. That is, unless the PS/2 were to use something different.

In fact the following device appears to be able to accommodate all of IBM's standards, including 2.88MB FDDs, so it does appear that the PS/2 was no different in regard to bitrate.

DP8473 Floppy Disk Controller:
http://www.datasheetcatalog.org/datashe ... 009384.PDF

"This controller is a full featured floppy disk controller that is software compatible with the uPD765A but also includes many additional hardware and software enhancements. These enhancements include additional logic specifically required for an IBM PC PC-XT PC-AT or PS/2 design."

"This controller incorporates a precision analog data separator. ... This provides optimal perform-
ance at the standard PC data rates of 250, 300 kb/s and 500 kb/s. It also enables optimum performance at 1 Mb/s."

So AISI the 720KB 3.5" drives would be operating at a bitrate of 250kbps, and the 1.44MB drives would be running at 500kbps. This would make them no different to ordinary FDDs.

As for why the PS1 drives gave you a better recovery rate, I can only imagine that they may have had better alignment tolerances, or perhaps their heads were more sensitive, or maybe the head coils were slightly wider. Whatever the reason, I can't see how it could be related to copy speed.

[Spildit]

@Spildit, I don't for one second question your data recovery experience with floppy diskettes. However, I do take issue with your explanation, and I do that as an electrical engineer. I also have some practical hands-on experience with the PS/2 Model 25 (720KB 3.5" FDD) and the PS1. I did once have the complete set of IBM's technical reference manuals for the Model 25, but I can't recall any specification data for its FDD. However, I do still have the IBM PC/AT Technical Reference Manual.

In fact here are the schematics for the original IBM PC/AT HDD/FDD MFM controller:
http://www.users.on.net/~fzabkar/PC-AT/FDC_HDC/

AISI factors that could explain the PS1's slow FDD copy speed would be track-to-track skew and head skew. In the ideal case the maximum copy time at 300 RPM would be ...

80 tracks per side x 2 sides per diskette x 0.2 seconds per revolution = 32 seconds

The IBM PC/AT standard allows for programmable head load/unload times and stepping rates, among other things. If PC DOS or OS/2 were to opt for more conservative values for each of these parameters than does MS-DOS or Windows, then it could result in the target sector passing by the head before it settles on the next track, which in turn would necessitate an additional revolution. This would significantly increase the copy time.

In fact I once played with a DOS utility that enabled the user to tune these FDD settings, including skew.

http://www.qnx.com/developers/docs/qnx_ ... ormat.html

As for RPM, AFAICT the 720KB and 1.44MB 3.5" drives both spun at 300RPM just like regular PC drives.

See http://retrotechnology.com/herbs_stuff/drive.html

The early 1.2MB 5.25" drives were dual speed (360RPM and 300RPM), but the latest ones were 360RPM single speed drives.

The data separator on the PC/AT FDD controller could be configured for 250kbps, 300kbps, or 500kbps data rates. If you were to slow the drive down, then the data separator's PLL wouldn't have enough range to lock onto the bitrate. That is, unless the PS/2 were to use something different.

In fact the following device appears to be able to accommodate all of IBM's standards, including 2.88MB FDDs, so it does appear that the PS/2 was no different in regard to bitrate.

DP8473 Floppy Disk Controller:
http://www.datasheetcatalog.org/datashe ... 009384.PDF

"This controller is a full featured floppy disk controller that is software compatible with the uPD765A but also includes many additional hardware and software enhancements. These enhancements include additional logic specifically required for an IBM PC PC-XT PC-AT or PS/2 design."

"This controller incorporates a precision analog data separator. ... This provides optimal perform-
ance at the standard PC data rates of 250, 300 kb/s and 500 kb/s. It also enables optimum performance at 1 Mb/s."

So AISI the 720KB 3.5" drives would be operating at a bitrate of 250kbps, and the 1.44MB drives would be running at 500kbps. This would make them no different to ordinary FDDs.

As for why the PS1 drives gave you a better recovery rate, I can only imagine that they may have had better alignment tolerances, or perhaps their heads were more sensitive, or maybe the head coils were slightly wider. Whatever the reason, I can't see how it could be related to copy speed.

Thanks for the explanation,

Now, for the important part;

What would you suggest for the OP to do in orther to get a better chance to recover the data from the floppy ?

[fzabkar]

Guess that my IBM PS/1 Controller and drive are as good as the Kryoflux lolololol

I'm guessing that your PS1's FDD controller would have been nothing special. The Read Data signal is TTL, so all the analogue-to-digital conversion would already have been done on the drive. All that the controller would need to do would be to extract the clock and data from the MFM stream. If you still have the controller, I'd be very curious as to which chip(s) it uses.

As for KryoFlux, it appears to be primarily a software solution. Even though it has its own controller, it still depends heavily on the quality of the drive for its success. It bypasses BIOS, but that's its only real advantage, AFAICT. It can read the actual GAP and ID fields, and it would be able to set up its own data rates, so that would enable it to handle non-PC formats. But IMHO, if you wanted a genuine data recovery solution, then you would need a specialised floppy drive. For example, I would think that a micro-stepping feature would be desirable. This would allow misaligned diskettes to be recovered. I would also want a drive whose read gains could be adjusted, thereby circumventing the drive's AGC.

[fzabkar]

What would you suggest for the OP to do in orther to get a better chance to recover the data from the floppy ?

Send it to you. :-)

[fzabkar]

What would you suggest for the OP to do in orther to get a better chance to recover the data from the floppy ?

There is a tool called Bad Block Copy for Windows. It works like ddrescue, but it works on individual files. You can use it to automatically reconstruct a single file from multiple corrupt sources.

http://alter.org.ua/soft/win/bb_recover/

In the old days I used DiskEdit from the Norton Utilities. It would identify all the sectors/clusters belonging to a particular file. You could then manually copy those sectors to a target drive.

Before doing anything, I would examine the diskettes for physical damage, eg circular scratch marks and mould, as you have already said. I lived in Singapore for 2 years where it is humid every day, so I know that mould is a very real problem.

[fzabkar]

And by the way, if the floppy that you are trying to read is a low density one (only one window to write-protect and no window on the other side of the floppy) modern USB floppy drives will not even read those !!!! (The majority will only read HD floppy)

I haven't come across those myself, but I wonder what would happen if you chose 720KB for your drive type in BIOS.

In fact I have an old 486 machine running Win95 DOS. It has a 3.5" FDD. If I choose a drive type of 1.2MB 5.25" in BIOS, then I can still read the data on a 1.44MB diskette without error, ie ...

copy a:*.* nul

However, if I choose a drive type of 720KB 3.5", then I get an Abort/Retry/Fail error.

The reason is that the 1.2MB and 1.44MB FDDs use the same bit rate for the data separator, namely 500kbps. The former rotates at 360RPM while the latter spins at 300RPM.

15 sectors per track x 6 revs per second = 18 sectors per track x 5 revs per second

15 x 6 x 512 x 8 = 18 x 5 x 512 x 8 = 368640 data bits per second

[Spildit]

Of course that by now i would bet that the OP have it recovered and we are arguing for nothing.

[fzabkar]

I prefer to think of it as a discussion.

[hhddrec]

Hi fzabkar and Spildit, you are two gurus.

thanks 4 your coments

I thin your two ways are good advices. sometimes maybe one baetter than other but all recovery cases are diferent and those two ways are very pretty.

[Spildit]

It would be nice to know if op got the photos from the floppy at the end...