5.25 Floppy Drive
 

I am trying to recover some old floppy drives with file system sysv4. I have successfully recovered all the 3.5 floppy disks, with the same file system, but I cant find a way to make linux recognize the 5.25 disks correctly. The bios has settings for the 5.25 1.2 and the 360 disks. Windows 2k has no probelm formating and writing to these 5.25 disks. I know the hardware is good and the bios settings work fine for windows. Any help would be appreciated. I have tried koppix, ubuntu 8.04 and 10.x and the latest versions as well.

Thanks in advance

Forgot to add the 5.25 Floppy drive is Teac FD-55GFR 7149-U5

You have two problems,...

First, is 5.25 floppy drive support compiled in your kernel?

and

Second, Reading this "sysv4" file format,... what is that 1970s era Unix?!?! You'll maybe have more luck with BSD? Anyway, you'll need filesystem support or maybe have to try testdisk...

You have two problems,...

First, is 5.25 floppy drive support compiled in your kernel?

Answer: Yes, I was just able to get the darn thing to read a fat 32 file that i created with windows.

the sysV4 Files are form an OS called Venix Mid 80's I believe.

I just e-mailed someone that is infoming me the 5.25 disks probably came from a DEC PRO system and is sending me a software imager to try.

Thanks for your quick responce.

5.25 floppies cane in 180k, 360k, and 1.2Mb at least, and possibly other sizes.

I did something like that - recovering an old CP/M 800k floppy, which a company was being charged £400 for a copy of. At the time (1990s), fdutils had a page on linux.lu. I emailed the maintainer, and was instructed on how to discover the format (8 x 1k sectors, 80 tracks). I was able to configure the 1.44MB drive as an 800K drive, and dd in a disk, and dd out copies. The guy wrote the thing up as a technical article on his site - I think it was the first practical use of the fdutils that anyone had found.

You may be the second :-P.

I believe that there is a low level Linux kernel i/o problem reading 360k floppies from a 1.2M 5.25" diskette drive.

I tried using FreeBSD and OpenBSD.

OpenBSD works!

It's dawning on me that it's probably the filesystem you're having a problem with.

5.25" disks are from the era of Dos 3.x - 6.x. For windows 95, there was a significant filesystem revision(Dos-7.x). You don't need module vfat; you need the old module msdos. msdos support in the 3.8.x kernels is for the partition tables, not the dos-6.x filesystem. It is difficult to provide support for both as theoretically vfat is/was backward compatible; But that was windows 95 era vfat. This was a horrible situation. Read compatibility was there. Writes by dos-6.x destroyed vfat systems, and file checks by vfat systems destroyed msdos systems. It is probable that backward compatibility has been dropped by Dos-7.x since.

Who still does that? Mebbe (just maybe) the Tomsrtbt system still has it. It's a floppy drive system. I think support was there in 2.4 kernels
http://www.toms.net/rb

Otherwise, go to a 2.4 kernel, which is not straightforward. Support might have made it into a 2.6 kernel, which would be easier. Do you really need that old stuff so badly?

I am assuming that your problem is the following:
You have some 5.25 inches floppy disks which have been formatted in a sysv format, and you are trying to
read them using linux. I am guessing that your 5.25 inches floppy drive is connected to the same controller
as the 3.5 inches drive so that the 3.5" drive is A: under Windows, and the 5.25" drive is B: .
In Linux, the drives should be respectively /dev/fd0 and /dev/fd1.

First question: can you read from the /dev/fd1 drive under Linux ?
have you tried to do dd if=/dev/fd1 of=floppy.image ibs=1024 count=360 ? If so, what kind of error messages
do you obtain ? If that operation succeeds, can you mount the file using the loopback interface (see man mount) ?

Second question: can you read MSDOS/Win2K formatted floppies from that drive i. e. have you tried, on
a Win2K formatted floppy to do a mdir b: ? Have you tried to write a text file in Win2K on one of these
floppies, and have you tried to read its content with mtype b:textfile.txt on Linux ?

Last question: if you try to do mount -t sysv /def/fd1 /media/floppy what kind of error message do you
obtain ? Is there anything in /var/log/syslog or /var/log/messages ?

Your problem may be caused by a too recent version of the Linux kernel, that does not support old 5.25" drives well.
I have an old 486 PC with Linux 2.0 and a 5.25" drive which can read old MSDOS floppies. If all else fails, you
should probably install an old Linux 2.0/2.2 on the Win2K computer to be able to read the floppies.

A few extra things:
What is the output of getfdprm /dev/fd[0-1] ? Have you looked at the info file on fdutils
and the page http://www.moria.de/~michael/floppy/ ?
You may need to use setfdprm(1) to make Linux read your sysv formatted floppies even if you can read
MSDOS floppies on Linux.

The reason I suspect that the low level device driver is in error is because I can use the OpenBSD "dd" command and copy a diskette to disk. Then I mount the file as a filesystem under Linux with a loopback and it works fine.

So the msdos/vfat filesystem software on Linux is fine.

Both Linux and FreeBSD seem to insert bad data to the input when using "dd" to copy a diskette to disk. And the result is unrecognizable as an MSDOS filesystem.

The diskettes were originally created on a 360k floppy drive and I am reading them on a 1.2M drive.

The problem might be historical. Linux was was written in 1991 when 5.25 inch floppies were no longer popular and the 3.5 inch floppy was the standard.

Just as Linux did not support the old Intel 286 chip, it may not have adequately supported the old 5.25 inch floppy drive.

Good work. It sounds like you have got your data, which, I hope, was the exercise.
Have you installed the fdutils package? That has low level commands to allow you to get to the bottom of many issues.

BTW, linux never was back ported to the '286 because the '286 was subnormal and had hardware limitations which made multitasking a very rough process. An attempt was made to back port linux to the 286, but it floundered without releasing anything, IIRC. There was several who also tried for multitasking or Beowulf type designs under Dos.One of these was the Transtec(Ireland) Hydra project, which bankrupt that company in the 1980s. There is a transtec found by web searching, but it's not the same outfit.

I am not sure about that. As I wrote previously, I was able to read 5.25" 360K floppies from 1991 with mtools on an old 486 PC running Linux 2.0. That was in 2009, so the floppies were already 18 years old. That does not square with
a defective device driver in the early versions of Linux. I was not using dd but the mtools programs though. Maybe
it is the Linux dd that has a problem with 5.25" floppies.

I had a 5.25" floppy drive which worked with the linux 2.0 kernels. 360k or 1.2M.

Around the same time I was configuring a 1.44MB drive using a 720k disk to be an 800k disk ojn a format I had worked out using fdutils. There is/was an article about discovering formats up on the site, which is the results of emails between me and the author. A 1.2M disk can be configured with a few commands bu you into a 360k disk, looking for the format you have.

I have been suggesting fdutils to you. Perhaps time to take them seriously? Alternatively, since you have read the disks under bsd, why not mark this solved, unless you want to invest time in duplicating that on linux.

Unless someting in the forum software has gone wrong, and some posts disappeared, I don't see any statement by the OP that he could read his floppies. Other posters did say they had various degrees of progress.

jlinkels