Backing up Japanese 3.5" disks

[Calpis]

Hmm, strange Windows can't deal with the filenames, I would have guessed it was having trouble reading a disk written by a 360 RPM "3mode/tri-mode" drive as seen on the PC-98.

[Flash]

Nothing "strange" about it - Windows is ages behind linux in terms of proper Unicode support. In linux you can name your files in any language supported in unicode, you can even mix korean, japanese, cyrillic etc. in one file name. I don't think that Windows will be able to display/open/copy such stuff properly

Hardware/format issues can be easily checked with dd or other raw dumping software - if there will be error then it's a hardware issue

[Jamtex]

What computer format are these discs in? The only difference between Japanese and IBM PC discs at DD level is that the Japanese discs spin at 360RPM rather then the 300RPM that the IBM PC discs do. Most external drives should support Mode 3.

Although you may have the language files installed, you have to make sure you have Japanese selected for non unicode programs, if you load up a command prompt you will notice that the \ symbol has turned into yen symbol if this is done. Then you should be able to read the discs. Without this, Windows will read the file names wrongly and treat some of the Shify JIS Japanese files names as control characters which will throw copying out.

DD disks for the PC-98x1, Sharp X68000, FM Towns and DOS/V all basically have the same format (FAT 12, 80 Tracks, 9 Sectors, 512 Bytes per sector) so reading and copying the files should not be a problem. I've copied non protected discs using nothing more then DISKCOPY with Windows XP and they are still readable on the PC-9821.

[Calpis]

No shit, you can mix characters in Unicode? What does Unicode have to do with anything???

Japanese filenames were Shift JIS, it's still extremely common to see SJIS files today. If Windows doesn't have the conversion table to read SJIS it appears as mangled extended ASCII dependent on your region. If you can't copy a file due to an invalid path then you can just rename the file, though that would clearly compromise the integrity of the disk. He already tried WinImage, WinImage is just as low-level as "dd", they both receive pseudo-raw sector data which doesn't consider filenames.

Obviously the issue is "hardware", and the most probable explanation is that the disk was written with a 3-mode drive at 360 RPM. Since disk controllers aren't smart enough to demodulate 360 encoded data at 300 RPM, it's necessary to get a 3-mode drive or perhaps the drive can be jumpered for 360 RPM. Also it's necessary to have 3-mode support in your BIOS because it's unlikely that Windows sets up the controller itself.

[Segafreak_NL]

What computer format are these discs in? The only difference between Japanese and IBM PC discs at DD level is that the Japanese discs spin at 360RPM rather then the 300RPM that the IBM PC discs do. Most external drives should support Mode 3.

Although you may have the language files installed, you have to make sure you have Japanese selected for non unicode programs, if you load up a command prompt you will notice that the \ symbol has turned into yen symbol if this is done. Then you should be able to read the discs. Without this, Windows will read the file names wrongly and treat some of the Shify JIS Japanese files names as control characters which will throw copying out.

DD disks for the PC-98x1, Sharp X68000, FM Towns and DOS/V all basically have the same format (FAT 12, 80 Tracks, 9 Sectors, 512 Bytes per sector) so reading and copying the files should not be a problem. I've copied non protected discs using nothing more then DISKCOPY with Windows XP and they are still readable on the PC-9821.

No shit, you can mix characters in Unicode? What does Unicode have to do with anything???

Japanese filenames were Shift JIS, it's still extremely common to see SJIS files today. If Windows doesn't have the conversion table to read SJIS it appears as mangled extended ASCII dependent on your region. If you can't copy a file due to an invalid path then you can just rename the file, though that would clearly compromise the integrity of the disk. He already tried WinImage, WinImage is just as low-level as "dd", they both receive pseudo-raw sector data which doesn't consider filenames.

Obviously the issue is "hardware", and the most probable explanation is that the disk was written with a 3-mode drive at 360 RPM. Since disk controllers aren't smart enough to demodulate 360 encoded data at 300 RPM, it's necessary to get a 3-mode drive or perhaps the drive can be jumpered for 360 RPM. Also it's necessary to have 3-mode support in your BIOS because it's unlikely that Windows sets up the controller itself.

Indeed, it's giving me some mangled ASCII characters (jokers and stuff) but the structure of directories and stuff is still there. The discs are mostly 'TDK MF-2DD Super EB Finecoat' discs. (if that helps, at all).

[Jamtex]

Have you gone into Region and Languages and made sure you have east asian language support AND selected Japanese for the language for non unicode support as I mentioned on the previous page? If not then go and do it... then you should find windows will magically display Japanese file names as long as you have a compatable external disc and you have not accidently written to the disc.

As for format, do you know which computer these were developed on? DOS/V, PC-98x1, X680x0, FM Towns, Windows 3.1(J), Windows 95 (Japanese), etc.

[emu002]

the old macs at my work used to be able to support 2mb high density floppies
Where as windows would only take up to 1.44mb ones

[Segafreak_NL]

Did that, the slash HAS changed into the Yen symbol but it wants to format the disk fist :( 'Disk is not formatted do you want to format it?'

[Flash]

Maybe i just don't get it, but you want to backup those disks, right ?

Then first make raw images with WinImage, linux live cd + dd etc. If it will go without errors and you'll get a few 720k images, just copy them somewhere to be on a safe side. And then you can open them somewhere. There's a lot of utilities that can open floppy images, virtual machines, or emulators like Dosbox or japanese computer emulator can mount them.

Best way - live cd or virtual machine with linux, you can just do something like sudo mkdir /mnt/floppyimg, then sudo mount -o loop <insert floppy image name here> /mnt/floppyimg and then open that folder in any GUI browser and rename Japanese names to english ones to avoid problems in windows. Or you can try it in windows with those Region and Languages stuff.

Just don't try to do anything on those real floppies.

Obviously the issue is "hardware", and the most probable explanation is that the disk was written with a 3-mode drive at 360 RPM. Since disk controllers aren't smart enough to demodulate 360 encoded data at 300 RPM, it's necessary to get a 3-mode drive or perhaps the drive can be jumpered for 360 RPM. Also it's necessary to have 3-mode support in your BIOS because it's unlikely that Windows sets up the controller itself.

In this case you won't be able to do anything with those floppies, you won't see any files, directories etc, you'll just get an error message when you'll try to access floppy drive, similar to one when you insert unformatted floppy.

[Druid II]

Can you copy one of the filenames here, it may be shift-jis.

[Segafreak_NL]

I'll do some pictures from my old Win 95 pc.

[Druid II]

A picture is cool but it's easier to ID shift-jis if we have the actual character string.

[l_oliveira]

Have something like Winhex on the old Win98 PC which can read the discs. Then with that image the discs. :)

[Segafreak_NL]

Okay this what my old DOS/Win95 PC gives me;



Obviously something's wrong with the file sizes..

Here's a string of one of the filesnames on the disk (bottom right one in the Win95 image above);

ﾕxﾇY・[._]

thats

[Jamtex]

The disc could be corrupt as the file sizes are a tad too large to fit on a disc, although did you do what I told you to do last time with regards to the non unicode programs? Do the same and then do a DIR in a cmd prompt....

[Segafreak_NL]

Hmm doesn't sound too good..Win95 doesn't support unicode right? I only changed those settings in Win XP (successfully) but Win XP wants me to format the disks before letting me do anything with them.

[pool7]

Did you have a chance to try under GNU/Linux?

[Nemesis]

The filesystem is corrupted, forget about trying to copy off the "files". Those filenames aren't in "unicode", what you're seeing there is garbage from a corrupted FAT directory listing, hence why your computer thinks there's 5TB of data on a 1.44MB floppy. What you need to do is take a proper image of the disk, and recover all readable sector data. You can then worry about trying to reconstruct the real files from the image.

To take a proper image of the disk, I'd recommend you use R-Studio (http://www.r-studio.com). You can use the demo version of the software to take a disk image, you don't need a license to use that function. If you want to try taking a disk image use the following process:
1. Make sure the disk is inserted in the drive before you launch R-Studio
2. Run R-Studio with admin rights
3. Select the disk drive from the list, rightclick, and select "Create Image"
4. Under the "Main" tab, select a "Byte to byte image". This will create a raw disk image (.ima).
5. Under the "Advanced" tab, in the "Read attempts" field, enter 10, to make it retry bad sectors a few times.
6. Press the "Ok" button. The image process should now run through and copy off all readable sectors from the disk.
7. Once the image has been created, rightclick in the "Log" window, and select "Save Log to File". If there are bad sectors, the log file will record the sector locations where they occur inside the disk image.

Once you've created the disk image, you can then try and reconstruct the file system. R-Studio itself is the best tool for this. You can open the disk image up in the software, and do a scan of the disk image to try and identify the filesystem and file contents. Note that every bad sector that can't be read off the disk is 512 bytes of missing data from the disk though. The more bad sectors you have, the more damage there is in the filesystem and the files themselves. In my experience 1.44MB floppies with bad sectors can usually be "encouraged" to read correctly, but it's a slow and difficult process. Backup as much readable sector data from the disks as you can first, then I can offer some advice about the bad sectors if you want.

[Segafreak_NL]

Oh dear, was worried that might have been the case. I'll try your process and post the outcome here.

[Druid II]

I could swear those filenames could be shift-jis but the forum mangles up the text when you post it here.

But Nemesis is probably correct.
Honestly, I would've been surprised if the data on those diskettes is still intact after so long... most of my floppies died on their own in months, even when safely stored.