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Unable to read entire TK50 tape - Suggestions needed.

 
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Respected Contributor

Unable to read entire TK50 tape - Suggestions needed.

I have attempted to read an older TK50 tape without much success. The tape is an older backup tape and contains some sources that are needed. The backup begins and reaches about 1/3 the way throught the tape then a controller error occurs. I am using a TZ87 drive and all the lights on the right hand side blink repeatedly.

Note:
1) I have attempted this with 3 different drives thus far with the same result.

2) Once the tape gets into this condition, I need to manually remove the tape and rewind it into the cartridge. No amount of power cycling or resets of any nature will rewind or unload the tape.


Any suggestions?

Thanks,
Dan
16 REPLIES 16
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Re: Unable to read entire TK50 tape - Suggestions needed.

If one or more of these drives is a TZ87 and these are not all TZ87N series drives, then I'd suggest ceasing recovery efforts as that just scrapes off more of that limited resource of readable bits of oxide, and calling upon a data recovery service.
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Re: Unable to read entire TK50 tape - Suggestions needed.

Dan,

Way back we regularly had similar issues.

If turned out, that reading such tapes with a non-SCSI drive regularly succeeded (with a number of "recoverable media errors").
SCSI however is unable to proceed past a single parity error.
( That is why we used to say that SCSI was pronounced like the Italian Scusi "I am so sorry" -- for the poor quality.
But SCSI was less than 10% the cost of solid DEC-style periferals, so ....

_IF_ you can sill find and operational TK50 or TK70 drive, you stand a fair chance. You WILL need patience! But NO way I can guarantee success. Just as Hoff said: it is already old stuff, and the repeated tries have done nothing to improve them!

Proost.

Have one on me.

jpe

Don't rust yours pelled jacker to fine doll missed aches.
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Respected Contributor

Re: Unable to read entire TK50 tape - Suggestions needed.

I have a TK70 drive that I can install into my VAX machine that I can try. I haven't as yet because of the need to install the TK70 controller. Maybe over this long weekend, I'll try that path.

Thanks for the suggestions.

Dan
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Re: Unable to read entire TK50 tape - Suggestions needed.

Dan, reading a TK50 with a TK87 is really stretching the envelope as it is. The TK70 would be much closer to native and I'd encourage you to try that. If that doesn't work I could check in the garage and see what model TK drive I have. That effort would be complicated because the host system was DSSI-based and is currently diskless.

Now if it were my data I might carefully try to fiddle around with the cartridge and make triple sure that the tape wasn't buggered inside the "can" so to speak. We used to have some bizarre experiences at a former employer where all our 40 production MicroVAXen had their reloadable personalities on TK and we never knew if the tape drive had a ton of drywall dust or a herd of dust bunnies inside the drive. Reloading was always a challenging toss-up.

If you can't get the data directly yourself we might trade contact info if your options dry up.

bob
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Re: Unable to read entire TK50 tape - Suggestions needed.

Thanks for the updates. I have multiple TK70 drives available that can be installed in a DSSI based system (still functioning after 10 years with 2 reboots...). I'll let you know how it works out next week.

I'll be resurrecting a couple of Flamingos this week end too. Should be fun.

Dan
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Re: Unable to read entire TK50 tape - Suggestions needed.

Any suggestions on how to remove the tape other than by dis-assembly and hand winding? The tape appears to be about 1/3 wound inside the drive.

Thanks,
Dan
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Re: Unable to read entire TK50 tape - Suggestions needed.

I have a number of table-top TZ87 drives to do TK50/TK70 recoveries. If you remove the drive from the enclosure (I just cut a hole in the enclosure), you'll see a Phillips screw that is in-line with the center of the cartridge.

GENTLY rewind the tape (counter-clockwise as seen from the underside of the cartridge) and it will wind back up into the TK cartridge. I use a wimpy power screwdriver to do this, since it takes lots and lots of revolutions to get it all back in.
http://www.stanq.com/charon-vax.html
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Valued Contributor

Re: Unable to read entire TK50 tape - Suggestions needed.

Call MSRC Company Inc., 603-642-6300, Brentwood NH. They can totally refurbish a TZ87 drive to like-new specs, including a new TK50 head.

My technical contact there was Matt Parker at extension 239, but it's been a few years since I spoke to him, so I don't know if he's still there.

You'll want to clean the head after each tape (or attempt). Use non-fabric cleaning wipes and isopropyl alcohol to clean the head -- you have to pull the clear (usually) shield off the inside of the drive to get to the head.

You might guess that I've spent entirely too much time inside the TZ87 hardware...

Unfortunately, if you pull a hard error on the drive, you're dead. There was some "diagnostic" firmware that would let you continue, but it was never released into the wild. Some very expensive recovery shops like OnTrack Data Recovery (http://www.ontrack.com/datarecovery/servicequote.asp?PartnerID=2337811) [yes, I'm a partner] might have that firmware. I've never asked.
http://www.stanq.com/charon-vax.html
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Respected Contributor

Re: Unable to read entire TK50 tape - Suggestions needed.

I was a bit surprised that a power cycle did not effectively rewind the tape abck into the cartridge. I would have normally expected this to occur. I just received a number of TK87 drives that I will test. But will wait until I attempt the TK70 drive. I just found a TK50 drive as well still wrapped in the packing envelope. I will try that as well.

Thanks for the suggstions.

Dan