VOGONS


First post, by LCKurtz

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Hello everyone. I have a couple of old files with names PCBACKUP(1).001 and PCBACKUP(2).001 that I backed up with pctools many years ago (when I was many years younger, I'm 86 now). The original files are long gone, and I would like to restore them for old time's sake. I have tried to restore them with dosbox and an old pcrestore file I found, with no luck. I'm not as good at this stuff as I used to be and I'm wondering if there might be someone out there that would have a go at it for me. The files have no monetary value, only sentimental value to me, and my son would like to have them. I could email the files to anyone who might be interested.
--Lynn

Reply 3 of 11, by Makus

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Hello Lynn,
Do you remember what version of PC Tools you used, DOS or Windows 3.1?
Are the files part of the same backup or are they 2 separate backups?
Because if they are part of the same backup the second file should have extension “002”.
The name of the files is strange because it exceeds the 8 characters allowed by DOS: have they been renamed?
Where did you copy them from?
Because it seems that Central Point Backup formats the floppies in a special format maybe readable only by a real floppy disk drive:
https://www.os2museum.com/wp/the-central-poin … -floppy-format/
Also there maybe should be a file with the extension “DIR”: Central Point CPBackup

Reply 4 of 11, by LCKurtz

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I just found an old r/w cd I have that looks like it has perhaps a better version of the backup. At least the names look better. I will send them to you later today (maybe tomorrow your time depending on where you are).
--Lynn

Reply 5 of 11, by konc

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A milestone in this effort is identifying the software that created these backup files.

-The name of the software and generated files changed from PCBackup to CPBackup (Central Point Backup), beginning in version 7. So it's a version earlier than that.
-The backup software wasn't part of PCTools (or didn't even exist, I'm not sure) until version 3. So your files are generated using version 3, 4, 5 or 6.
-Versions 3, 4 and 5 use a non-standard DOS format. The disks aren't readable from DOS to get these files.
-So it has to be version 6 (which even mentions in the readme.txt that it's not compatible with backups created from older versions)

And indeed, attempting a small backup using version 6 produced a file with the same name as yours, exact same size, similar internal structure and even padding in the end. I'm fairly confident that 6 is the correct version.

SCREEN01.jpg
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575 views
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Public domain

But... I'm not confident that the files you sent are not somehow corrupted. Yes they are part of a multi-disk backup set (maybe even 2 different sets) and you only sent one part, but the software has the capability to rebuild for what you have and partially restore whatever exists on that part. Yet nothing can be restored from these 2 files. So if you found another copy as you wrote above, it might be good to share it too.

Reply 7 of 11, by Makus

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@konc thank you for clarifying the differences between the software versions: I missed the inversion of the first 2 letters of the software name.
@LCKurtz as you say, your PCBACKUP.001 file is very strange, it doesn't seem to be encoded like the other 2.
Anyway I did some tests with PC Backup V6: during the backup it also creates PCBACKUP.INF and PCBACKUP.DIR files.
If PCBACKUP.DIR file is deleted, the backup can no longer be restored even with the Rebuild function.

Reply 8 of 11, by konc

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Makus wrote on 2024-05-30, 10:11:

Anyway I did some tests with PC Backup V6: during the backup it also creates PCBACKUP.INF and PCBACKUP.DIR files.

Only if you backup to a fixed disk directory. If you do the backup on floppy disks only one file is written, as per my screenshot in a earlier post.

Reply 9 of 11, by konc

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LCKurtz wrote on 2024-05-29, 16:07:

Thank you very much for the info konc. I will email you the other set right away.
--Lynn

After investigating more, I don't have good news. As @Makus already mentioned, the problem is the missing directory information because of the way PC-Tools v6 stores it.

When creating backups to a fixed disk location, the process is straight-forward: 2 additional files (.INF and .DIR) are created. If they are missing, I see no way of restoring anything but then again people would copy those too.

When creating backups to floppy disks the process changes: the program formats the disks creating its own, non-standard DOS boot sector which needs to be detected for a backup disk to be recognized and accepted. But it also encodes the directory information (the equivalent of.INF and .DIR files) in sectors not occupied by the main file and unfortunately this information is not visible as files. Assuming that your backup was done using floppies, that's why you weren't able to see it and copy it. Again I see no way of recreating this missing piece of information, it's not even readable text but binary. Sorry!

What a stupid approach... I can only imagine how many people ended up with useless backups because of it. Of course they changed it in the next version and since v7 even floppy backups contain the directory information as a visible file.

Last edited by konc on 2024-06-01, 07:43. Edited 1 time in total.

Reply 10 of 11, by Makus

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Thank you @konc for your deep technical explanation.
@LCKurtz, unless you have kept the original floppy disks, I'm afraid there's nothing you can do.
If you happen to find them, you could try creating images with a USB floppy drive and WinImage utility.

Reply 11 of 11, by LCKurtz

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Many thanks to both of you. I can't say I am surprised by the outcome though. Several years ago in a moment of house cleaning I disposed of all my floppies-- won't ever need these for anything again. And as for the originals that the floppies backed up, a techie where I worked was going to add a linux image on my computer and managed to reformat a spare drive that he was supposed to leave alone and that had the originals. So I now have a couple of working DOS apps I wrote that I no longer have my source files for. Luckily for me, it's not an important loss. I guess one takeaway from this experience is to "never throw anything away", but that has its own issues. Anyway, thanks again for your time and effort.
--Lynn
http://math.la.asu.edu/~kurtz