[rescue] QIC Tape Archival

[Patrik Schindler]

Hello Kurt,

no offense intended, nor taken. Just wanted to make clear that I do have experience and am not just a random guy with merely a working tape drive. :-)


Am 05.12.2024 um 19:48 schrieb Kurt Nowak via rescue <rescue at sunhelp.org>:

> I'm not questioning your experience or expertise. I have experienced many tapes with the band stuck to the tape as I had described. They were even stored in a relatively cool place.

Interesting. Thanks for pointing out!

> It could be that they were not re-wound when I found them and all yours were rewound?

Hm. I don't see how this makes a difference in terms of transport belt sticking to the tape surface.

> But yes, most just snap instantly with the acceleration or they are already snapped - even brand new ones stored in plastic wrap are opened up and you can see the snapped band inside.

I obtained some NOS, sealed ones lately, none failed. :-)

> Regarding them turning into a tape salad as soon as they snap - I was being dramatic....

Thanks for admitting. :-)

> these things just weren't designed to last 30+ years.

Sadly, yes.

> Then you have to take it apart and carefully rewind them by hand.

And not generate salad or kinks by doing so. Been there, done that (accidentally), undone the salad. On a side note, DDS seems to be rather tolerant about kinks in the tape.

> Whatever it is, I've experienced it first hand more times than I want to admit. Tapes are fun when they work but a major pain when they don't.

I fully agree.

> I'd be interested to know what your secret to success is?

I don't really know. Maybe I was just lucky so far? I have not (yet?) handled dozens of tapes, but one dozen maybe. In earlier times I cannibalized low capacity cartridges of their belts to save the large ones.

Brands I have are 3M, Imation and BASF.

> Yes I know the bands are not made of rubber but some special compound of very thin plastic which, like all plastics, degrades over time. It's unfortunate that someone hasnt made replacement bands for these tapes, since there seems to be a big demand for them in the vintage computer community.

Well, I guess this is an extreme niche market and thus very uninteresting.

> The plasti-band method that YouTuber Curious Marc uses just didn't cut it for me in the past. The bands that you get are all very in size and most are too tight - plus they are just too elastic. Again, very much hit and miss.

I have seen the plastiband trial videos and it's amazing how tolerant this belt technique is against "mismatch" in width and tension.

Last time I checked, I was unable to find a source for those plastibands in Europe.

> Once they are sticky, I don't think alcohol will save them - the material is already decomposing and I don't want to risk damaging the tape.

I'm 100% convinced that alcohol can't undo the decomposition damage already done. There is no substitute to replacement.

I have successfully revived an Apple LaserWriter from 1986 some years ago by cutting and filing silicone (polysiloxane) rubber rolls from various printer replacement parts in the "everything else" carton to according size. That's what I'd try with a failed roll in a drive.

I think decomposition of silicone rubber doesn't convert it to a bitumen like substance but shows a hardening, crumbling result.

The Laser Writer's paper pickup rolls were decomposed to a state where the material literally dripped down to the remaining paper sheets in the paper drawer.

> You just have to give them the fingernail test (after cleaning) and use your best judgment.

Well, there are two points to consider. Stiffness and slickness. Most often, rollers are affected by both conditions, especially in printers. Stiffness results in easier abrasion of rough material quality, resulting in slickness. The abrasive roughness of paper sheets helps this — in printers.

Slickness might cause slip and thus wrong or uneven tape transport. I don't know how much slip can be compensated by the electronic clock extraction from the tape's magnetic flux, clocking the further logic accordingly. I guess for writes, slip might result in unreadable tapes, even on the same drive, if it's sufficiently uneven. Slickness can be compensated somewhat with alcohol, by dissolving a thin layer of rubber and thus introducing some roughness. Another possibility is using sand paper. Both techniques involve some means to evenly rotate the roller to keep it round and not introduce edges, resulting in uneven transport and additional vibrations and thus noise.

Stiffness (and too tight plastibands) cause additional work for the transport motor, maybe leading to overloading it, or causing the transport roll to more easy slip on its counterpart in the cartridge.

> Some people have reported success with surgical tubing, but I question the roundness of that material.

Interesting approach. I feel that material might be too smooth. But I have no first hand experience.

> But I guess whatever works right?

Indeed!

:wq! PoC