How to backup/evacute a vintage hard drive that has Stacker 4.0 compression utility?

[Bill-kun]

I purchased a used vintage hard drive that I would like to back up before I clear it for my own use. It is a Miniscribe model 3650, 42 MB. It has PC DOS 7.0 on it and it is bootable.

When this hard drive is connected and I boot up (either from the 3650 or a floppy), the boot up screens include the following message:


I looked this up and WinWorldPC says Stacker was a wildly popular hard drive compression program; version 4.0 was 1994.
https://winworldpc.com/product/stacker/40

In the first life of vintage computers, I never used compression programs. I always considered that the reduction in access time was not worth the gain in space. So I don't know how to use any of them. I also am now of the opinion that it adds far too much difficulty in backup and recovery, to the extent that there is a risk of data loss.

Compression utilities seem to make it very hard for me to back up the hard drive, because:

1. A dir of the contents of the hard drive shows that there are many more bytes free on the hard drive than the hard drive physically has, which is at best confusing to me. I can't figure out if I am just supposed to be able to use ordinary DOS copy commands to copy files onto floppies or what, let alone how much space the files would take up on the floppy if I did.

2. The hard drive frequently gets a second partition put on it (sometimes labeled "HOST_FOR_C") which has completely different contents, or a huge compression file, example 40 MB.; can't just copy that 40 MB. file onto floppy disks.

3. The added partition makes using multiple physical drives that much more complicated. If the compression utility starts pointing to the wrong drive letter because I've connected 2 physical hard drives, it could start writing the compression files to the other physical hard drive.

The real problem: In addition, having this hard drive connected, even as the only physical drive, regardless of whether booting from the hard drive or a floppy, it is impossible for me to use either of the floppy drives for anything but booting. If I try to do a dir on the boot floppy, that works, but if I put a different floppy in drive A and do a dir, or try a dir on drive B regardless, the floppy drive light in question turns on, then off, and the computer hangs up!

How do I copy files off of this hard drive??

Here is a "dir /s" of the 3650 if it is the only hard drive connected: M3650.TXT

Here is a "dir /s" of the 3650 if it is connected as the secondary physical hard drive: M3650_ST.TXT

 

[Timo W.]

HOST_FOR_C is the actual real partition. It contains a large image file that Stacker mounts as C:. This is where the compression happens.

All you need to backup is what's on C:.

 

[Bill-kun]

Sorry, all you've done is make me more confused.

HOST_FOR_C is the actual real partition.

Please define "real." In this case, drive C on the 3650 is labeled "TURBO-286"; drive D on the 3650 is labeled "HOST_FOR_C". But--

Drive C from the 3650 only appears when the 3650 is the primary/sole physical hard drive, and then drive D on the 3650 cannot be seen.
Drive D from the 3650 only appears when the 3650 is the secondary physical hard drive, and then drive C from the 3650 cannot be seen.

HOST_FOR_C is the actual real partition. It contains a large image file that Stacker mounts as C:. This is where the compression happens.

Drive C from the 3650 results in a "dir /s" that is 37 kB. long and totals "24.9 MB." of files (presumably compressed).
Drive D from the 3650 results in a "dir /s" that is 1 kB. long and totals only 267 kB. of files.

All you need to backup is what's on C:.

Given the above info I added, is this still true? Can I totally ignore drive D from the 3650 and just copy off drive C, then repartition and reformat?

 

[Timo W.]

"real" as in what's defined in the partition table and fdisk.

HOST_FOR_C is the real C: - the primary partition that is on the drive. When Stacker loads, it will re-assign the drive letter to D: (or whatever is the first free letter) and mount the image file to be seen as C: by the user. Stacker will then try to hide D: (afaik) to make sure the user does not accidentally mess with the files there, as that would completely wipe all data. Of course, if you add a second hard disk, letters will shift, as D: is no longer available in that case.

So yes, all you need to backup is C: with Stacker loaded.

 

[Bill-kun]

Okay, thank you. I never knew the drive letters get reassigned. That clears up that info.

Now the obstacle becomes: How to I get files off of the drive when the drive being connected seems to be the cause of not being able to use the floppy drives?

 

[eswan]

My tool of choice would be LapLink, reliable but slow. Would require another dos machine with enough free space. Easy to 'push' the client from one machine to the one without working floppies.

 

[jafir]

You should be able to make a boot floppy with a config.sys with something like:

DEVICE=C:\STACKER\STACKER.COM C:\STACVOL.000
DEVICE=C:\STACKER\SSWAP.COM C:\STACVOL.000 /SYNC

(you'll want to look at the config.sys on host_for_c to see what the exact name of your stacvol.000 is, it's hidden by default. I don't see that in your DIR, so it might be hidden, use attrib in the DOS directory to look for the hidden files)

 

[Trixter]

I'm not sure I understand the issue here: Whether the drive is compressed or not, just copy the files off of it like you would any drive. Don't treat it any differently. Once you have the files off, just repartition/format/etc. from a clean boot disk.

I wouldn't try to copy the compressed volume; that just makes it more difficult to access the files later.

If you're still freaked out by the compression, Stacker comes with an "un-compress" util to put things back to uncompressed. Type "stac" at the DOS prompt after booting off the hard drive and it will tell you if you need to delete some files to make room for the uncompression procedure, or just start the procedure.

 

[Bill-kun]

I'm not sure I understand the issue here: Whether the drive is compressed or not, just copy the files off of it like you would any drive. Don't treat it any differently. Once you have the files off, just repartition/format/etc. from a clean boot disk.

I wouldn't try to copy the compressed volume; that just makes it more difficult to access the files later.

If you're still freaked out by the compression, Stacker comes with an "un-compress" util to put things back to uncompressed. Type "stac" at the DOS prompt after booting off the hard drive and it will tell you if you need to delete some files to make room for the uncompression procedure, or just start the procedure.

The problem was that I was backed into a corner in terms of being able to copy off any of the data from the 3650. I'm out of the corner now, but the following were the obstacles.
1. I could not boot with both the 3650 and any other hard drive.
2. If I booted from the 3650 as the sole hard drive, I could not use either of the floppy drives. The computer would hang up immediately if I tried.
3. If I booted from drive A, I could use that boot floppy and the hard drive, but as soon as I tried to use any other floppy disk in either floppy drive, the computer would likewise instantly hang up.
4. I even tried booting from the 3650, then running STAC to try to change the Stacker options or do an Uncompress command, or to get a stack report. I got into the Stacker screen, but as soon as I tried to give Stacker any command, the computer once again instantly hung up. I was able to run Sierra's Hoyle Volume 1 which was on the hard drive, but that's as far as I bothered to go in running anything directly.

Thankfully, my one way out was to put File Maven 3.0 (which is less than 360 kB.!) on the 1.44 MB. boot floppy then use it to do a null modem transfer to another vintage computer. That took a lot of time to arrange because all the hardware had to be in the same location.
1. That was finally successful and I got all the files with no problem!
2. In doing that back up, I find that the copies I made of the files on the hard drive match exactly, to the exact number of bytes. So that is good.
3. There were 24,951,498 bytes occupied and transferred. Because the natural capacity of the 3650 is 42 MB., I suppose none of the files were actually compressed.

Now that I'd successfully created a full backup, I was ready to reformat the 3650 hard drive for use in my own purposes, but:

Trying to reformat using "A:\>format c: /s" resulted in the following output:

Formatting 74.38 MB.
Not ready
Format terminated.
Format terminated.
​

"A:\>fdisk" showed me that there was a single PRI DOS partition of 40 MB.
I deleted that and created a new PRI DOS partition for 100% of the disk size.
In trying "A:\>format c: /s" again, this time it succeeded, and showed:

Formatting 40.23 MB.
Format complete.
System transferred
​

Now I finally, finally have a secondary hard drive for my Dell System 200, giving it 85 MB. in total! Huzzah!

 

[Samir]

Glad you got this sorted out. The kids with their modern computers and issues don't have a clue how hard our problems were back in the day.

One of the best solutions I found for getting information off another computers using just a serial or parallel laplink cable was Microsoft's Interlink. You had to run a driver on the destination computer that would be 'seeing' the drive, but on the source computer is was an easy little exe called intersvr.exe (if I remember this right), and it would allow the system on the other side to get a standard drive letter so you could use any program you would like and not be limited to laplink or other serial transfer programs. I believe Interlink came with MSDOS 5.0. Hope this helps someone out there!