Nekonomicon - Backing up DEC tk50 tapes to cdrom

antagonizt
Who joined Aug. 24, 2012, 8:52 a.m.
and authored 10 notes

Wrote the following at Dec. 16, 2012, 3:22 p.m...

I picked up a VAXstation 3100 with a tk50 tape drive and 10 tapes. They appear to be ULTRIX and VMS installs and software. I'd like to backup these tapes so if they become damaged the software isn't lost. Does anyone have experience doing this or similar?

I know nothing about tapes. I have access to a PC with Linux and SCSI that I could hook the tape drive to. Could I just do a dd from the drive? I tried mt and tar commands but they appear to not be tar archives.

Ideally I'd be able to convert the OS install tapes to CDROM install media.

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antagonizt
Who joined Aug. 24, 2012, 8:52 a.m.
and authored 10 notes

Wrote the following at Dec. 16, 2012, 4:19 p.m...

AQ-LV82A-BE U-32 v2.3/UWS
AQ-LX08H-BE VMS V5.4-1 BIN
AQ-PCAYA-BE ULTRIX/SQL V1.0 (VAX)
AQ-KU57A-BE ULTRIX WS V1.1 UNSUPP
AQ-KU57A-BE ULTRIX WS V1.1 UNSUPP
AQ-PHLZA-BE ULTRIX PAKS
AQ-EE50H-BE DECNET-ULTRIX V4.2 VAX
AQ-KU57B-BE ULTRIX WS V2.0 UNSUPP
AQ-PEWJC-XH PATHWORKS V4.1 DOS FOR ULTRIX
WANmanager 1.1.2 for VAX

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SAQ
Who joined July 19, 2006, 7:37 a.m.
and authored 5590 notes

Wrote the following at Dec. 16, 2012, 8:59 p.m...

You can dd to a file, but you'll have a raw tape image that may or may not be usable without writing out to tape again. The VMS stuff will probably be in BACKUP format, and I think that each tape file is one part of the saveset - you can always copy them over and try. ULTRIX might be in tar format tapefiles or CPIO (I think tar, as ULTRIX is BSD). The first file on the install tapes will be the standalone backup or install program image - that may change for CD installs.

The short answer is go ahead and dd off each file - it will be a backup, but you may have to extract from tape if you're going to do an alternate install (I dd'd some IRIX stuff, then had to drag the tapes back out to distcp over the files so they'd be in a useable form. Keep both - I still have the dd backup so I can write out boottapes easily if necessary.)

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kjaer
Who joined May 7, 2008, 6:47 p.m.
and authored 281 notes

Wrote the following at Dec. 17, 2012, 8:03 a.m...

SAQ wrote:

You can dd to a file, but you'll have a raw tape image that may or may not be usable without writing out to tape again. The VMS stuff will probably be in BACKUP format

The BACKUP tapes are likely to use blocks of varying sizes. dd will indeed back them up, but you will need to do some extra work to capture the sizes of the individual blocks (and make use of the information again during writing), or else a copy of the tape you make from the dd image will not be usable.

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smj
Who joined Nov. 12, 2007, 7:54 p.m.
and authored 935 notes

Wrote the following at Dec. 17, 2012, 12:08 p.m...

Ooof, not sure if you'd be able to build a bootable CD from tape files. We used to duplicate these tapes for distribution within the university I worked at, but that was around 1990 - I've completely forgotten how we did it for VMS.

I know for the Sun OS tapes on QIC cartridges we used tputil, which Sun provided to us, but you might want to look for copytape as tputil wasn't FOSS (see this thread , and maybe this one - use "comp.sources.unix" as an additional keyword if you plug "copytape" into Google, it's still in BSDish ports trees. Or just go to the source at gatekeeper.dec.com ).

I think it would have a reasonable shot at working with the ULTRIX tapes, and if so you might as well try the VMS tape too.

Please make sure the write-protect switch on your TK50 cartridges is in the locked/protected position!

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antagonizt
Who joined Aug. 24, 2012, 8:52 a.m.
and authored 10 notes

Wrote the following at Dec. 17, 2012, 3:19 p.m...

Thanks for all the help. Unfortunately it's all for naught, the tk50 drive is giving me the rapid red blinking of death, and no amount dust-off seems to help. I've got the thing taken apart and have been blasting it with compressed air hoping it will pass the self-test, but nothing so far. Maybe some else on the forum would like to take this task on?

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iainmaoileoin
Who joined March 23, 2015, 3:38 p.m.

Wrote the following at March 23, 2015, 3:42 p.m...

red blinking light
Often the tacho is dirty/clogged.
It can be a difficult beast to get to but is at the rear capstan.
Once big screw down the back of the ribbon cable (take care) opens up the tacho and the plate.
Clean with an air brush. Dont bend the splines dont touch the wee bits.
reassemble with care.
Worked for me on four "bad" drives.

robespierre
From Boston
Who joined Sept. 12, 2011, 2:28 p.m.

Wrote the following at March 23, 2015, 5:18 p.m...

for backing up tapes you need to understand the tape format pretty thoroughly... is it fixed or variable block size? TK50 can use both on the same tape, although normally it won't let you change the setting for partial writes.
how do you plan to preserve file marks? normally when you use dd(1), the transfer will terminate at each file mark. but this may be something different than what you think of as a "file". and dd doesn't actually know anything about end-of-tape signaling, which presents a problem.

kjaer
From Seattle, WA
Who joined May 7, 2008, 7:47 p.m.

Wrote the following at March 24, 2015, 11:20 a.m...

If you want the tapes imaged, that's something I can do for you if you're willing to ship them to me. I suppose in that case I should also verify my TK50s are still working, since it's been a while. Most of the tapes I've been transferring these days have been QIC.

HP/DEC/Compaq

Backing up DEC tk50 tapes to cdrom