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Option 61C Meridian Mail Tape Drive failure?

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BSmith01

Systems Engineer
Mar 29, 2023
14
US
I am working on an OPT61C with Meridian Mail (RLS12.14.1) and the tape drive seems to keep eating the backup tapes. I've tried multiple cleanings and have new backup tapes (Tape Cartridge - Imation Magnus DC6250 2.5/5Gb SLR4 Data Cartridges (46168)). Not sure whether its the tape drive itself or that the drive was just extremely dirty, but if I have to replace the tape drive, what would the procedure be? I can't seem to find the documentation on this anywhere?! The tape drive is an NT6P05BA, module is an NT6D45AA. I am having the new tape drive and cartridges shipped to site and just want to make sure I have all information needed to fix the issue.
 
If you have Meridian Mail 12, then your drive has to be very old. I'm surprised that it's still in service. Just goes to show how good the kit was.

I'm not sure if it's just a case of swapping out the drive as the hard disk must still be working fine.

Firebird Scrambler

Nortel & Avaya Meridian 1 / Succession & BCM / Norstar Programmer

Website = linkedin
 
Yes, this system is very old. I am hoping that doing a few cleanings on the tape drive unit will have corrected the issue with the drive eating the tapes so I wouldn't have a need for replacing the drive itself. Won't know for sure about that until I have the new tape cartridges on site. But since I haven't replaced a tape drive before and don't know if the drive is good or bad, I was wanting to verify the procedure in the event I would have to replace it. Problem is, I can't seem to find the documentation that covers this? If I replace the tape drive (NT6P05BA) would I need to power down the shelf or is it "hot swappable"? And will this cause Meridian Mail to go down if I don't need to shut off power as I don't have a backup cartridge currently since it was eaten. Just wanting to do what I can to keep from having the mail crash and not be recoverable.
 
Unfortunately those drives are degrading internally and in their old age have a tendency to eat tape cartridges. Cleaning likely won't get you much improvement as the cleaning process just removes accumulated tape oxide from the read/write heads.

If you look inside the drive with a flashlight you'll likely see that the rubber captsan roller isn't in very good shape. As the rubber ages it starts to disintegrate and lose its shape and grippiness. Because of the way QIC cartridges operate, and how they use that capstan to move the tape through the cartridge by way of friction this means the tape gets moving at a decent speed and then things get out of sync in the cartridge and the tape material gets tangled up or snaps.

In addition to the capstan issues, all of the DC6250 tapes you can find out there today are well past their expected lifespan, even new sealed ones. There is a vinyl band "belt" inside that usually either gets too hard and snaps, or stretches and no longer keeps the two spools in the tape moving in sync.
 
That's what I was thinking on the drive as well. Issue now is that I've found documentation that describes what needs to be done. NTP 555-7061-250 makes it clear that the module will have to have power shut off in order to replace the tape drive. My hope is that I'll get lucky and the drive will have only been dirty as I don't necessarily look forward to a shut down of the module without a known good backup cartridge at this point... I will definitetly check the rubber capstan roller though. I'll update once I've done the work with the outcome.
 
These drives and tapes are really quite old now, and they're a format that has a particular problem:

QIC tapes have an internal rubber belt that is used to drive the reels of tape, and it degrades with time. There's some variety to the failure modes of rubber (some get hard and crack, others stretch with no other visible problem, and some turns to sticky goo that gets on everything) but the general idea is that very few tapes of this format are working out of the box these days. In a scenario where you absolutely must recover the data on a tape, there are ways to 'fix' the tape long enough to read it into a modern PC, but these generally shouldn't be considered to be a viable backup option anymore.

The other common failure points in the drives themselves are the rubber parts there: belts, and the pinch roller (at least I think QIC uses a pinch roller).

I believe Meridian Mail uses SCSI tape drives, so there may be something a bit more reliable that could be swapped in for backups, but it's down to whether the OS that Meridian Mail runs on is generic enough with SCSI tape support that it would work with a different drive. There's also a few modern devices that support tape emulation, even Nortel used some of them in the DMS-100 to replace the aging DDS tape format in a few places.

At this point, something as old as Meridian Mail is frankly getting into the vintage computing era of electronics equipment, and you might have to look to some of the techniques that community uses to keep these old systems going.
 
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