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TDS-754C Renders Tektool floppy backup unreadable

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amaschas:
Hey all, I have a TDS-754C that I've posted a few threads about as it appears to be a singularly problematic device. It has various problems, not communicating over GBIP when in unlocked mode being the primary issue, and I'm trying to dump the NVRAM EEPROM using the tdsNvramFloppyTool-extra tool in the tektool repo so I can avoid bricking the device while working on it, but unsurprisingly I've run into a bizarre issue. The scope seems to write to the floppy fine, and I can see the backup files on the floppy, but the backup process appears to have altered the floppy filesystem such that nothing can be read from it. I've attempted formatting the floppy both on a windows machine and in the scope itself, and the backup seems to create files on the floppy in both cases, but nothing can be read from the floppy once the backup has been created.

My only option for reading/writing the floppy is a USB floppy drive, which reads and writes everything fine _before_ the firmware backup, even if I've formatted the floppy with the oscilloscope, but afterwards it only shows the files on the drive, reading and writing throws a variety of errors depending on which operating system I'm trying to use.

Just as an example, I'm current using a Ubuntu system to try to read the floppy. I format the floppy in the scope, move it back to Ubuntu, copy dumpall.app and startup.bat on the floppy, then insert the floppy into the scope and power it up. A few seconds after powering up I get a message that the backup succeeded along with a beep. When I check the floppy in Ubuntu again, I see that the original dumpall.app and startup.bat have been renamed to d and s (this doesn't happy every time), I can see all of the files on the floppy, but trying to copy them results in "Error splicing file: Input/Output Error".

I'm honestly leaning towards getting rid of this scope since it's been so much trouble at this point, and appears to be causing problems that no other version of this scope does. But I figure if I can at least backup the memory I can start making more drastic changes.

44kgk1lkf6u:
Since the long file names got corrupted, I would try to make it easier for the oscilloscope by making sure that all the file names are 8.3.  That is, naming the files DUMPALL.APP etc. and making sure that no unnecessary files exist such as the system volume information thing if the floppy was accessed by Windows after being formatted.

If it is the computer giving the input/output error, dmesg usually contains a more specific error message.

My oscilloscope has the opposite problem.  It can copy files from the hard drive to a floppy but has problems copying files from a floppy to the hard drive.  I have only had to copy files to the hard drive once.  I ended up using GPIB.

I don't have much experience with floppies.  But there should be plenty of information on what to do if a floppy drive doesn't work right.

PA0PBZ:
After the backup succeeded can you see the files on the floppy using the scope? (I assume that you can list the files there, I don't have one.) If there are only 2 or 3 files on the floppy they occupy the same directory sector and the scope has to write that sector back to update the directory. If you can see the files on the scope my guess would be that the floppy head(s) are misaligned. Also, make sure that the floppy is of the correct type, another guess from me is that it should be a 720KB floppy and not a 1.44MB.

nctnico:
Mis-alignment between drives is the most common problem AFAIK. Unfortunately the quality of floppy-disk drives has fallen a lot since the old days which makes exchanging data between two systems using floppy disks a huge challenge. What may help is to format the disk on the target machine and then try to read it using a PC attached disk drive.

TERRA Operative:

--- Quote from: PA0PBZ on December 01, 2024, 03:30:08 pm ---After the backup succeeded can you see the files on the floppy using the scope? (I assume that you can list the files there, I don't have one.) If there are only 2 or 3 files on the floppy they occupy the same directory sector and the scope has to write that sector back to update the directory. If you can see the files on the scope my guess would be that the floppy head(s) are misaligned. Also, make sure that the floppy is of the correct type, another guess from me is that it should be a 720KB floppy and not a 1.44MB.

--- End quote ---

These scopes do use 1.44Mb HD disks.

My money is on misaligned heads too.
A good excuse to install a floppy emulator... :)

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