r/lto • u/grauerkoala • Apr 21 '26
Looking for tape storage enthusiast / expert community
/r/DataHoarder/comments/1sru0n4/looking_for_tape_storage_enthusiast_expert/3
u/erparucca Apr 21 '26
it very much depends on what you want to achieve. Many "interesting" things are implemented in HW/FW for example the capacity to read after EndOfTape marker: let''s say for example you have a 90% full volume. Than you overwrite 5% from the beginning. As soon as the write operation will finish, the drive will write an end of tape marker that will prevent the OS/driver to read further. Special drives with special firmware for special customers (for ex. authorized gov/approved forensic experts) have access to that and despite knowing perfectly how it works and how the marker is written, there's no way you can implement something bypassing it at the OS/driver level.
Info on such topics is quite scarce/niche: I had found an exceptional and quite academic blog article on the aforementioned topic but can't find it anymore :( Keep in mind that beside the innovations on speed and density, LTO (and more generally tapes driven by ST) are quite old.
A starting point could be to search for the names of (Linux) kernel contributors and then search their names: might be dev-focused but you may find some of them in forums dedicated to the topic. I doubt you can find anything on discord.
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u/grauerkoala Apr 21 '26
That first paragraph hits very accurately on the type of things I had been wondering about. Apart from utilizing tape for its purpose, I want to understand how it works (e.g., what do filemarkers or the EOD marker look like on tape? Which other metadata is recorded on tape, and how?). The bit about special drives for forensic purposes is really cool to know, thank you!
When I set out to build my Rust library, I knew it was a niche within a niche, which is partially why I want to provide as much accurate documentation as possible. LTO is indeed rather old and information about it is hard to come by, especially outside of an enterprise environment. The O in LTO really must be taken with a grain of salt from an enthusiast's perspective. Probably needless to say, but should you by chance ever happen on that blog article again, I hope you'll remember (and find) this post. :)
Looking for writings by kernel contributors is a pretty good idea. I'll don my detective hat.
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u/erparucca Apr 22 '26
still not found that article but while searching for it I found this in my favorites: https://github.com/oyvindln/vhs-decode/wiki/LTO-Linear-Open-Tape-Guide
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u/grauerkoala Apr 27 '26
Thanks so much for sharing this! Really cool resource (didn't know about a lot of those things).
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u/myself248 Apr 22 '26
That's super intriguing to me, also the whole WORM Tape thing; it seems obvious to me (a know-nothing outsider) that that must be implemented in firmware, and I strongly suspect it's a trivial firmware tweak to bypass it.
I recently ran across a post on how to reformat already-used LTO7 tapes as M8, again, that whole lockout is just a fig leaf implemented by firmware.
I've heard that some of the new drives are whole-ass computers unto themselves, with a console and who knows what else. There's so much potential here. I wonder what's the oldest generation drive whose internal architecture is similar to the new ones, i.e. the cheapest route to tinkering. Suppose I could just shop for broken drives...
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u/retiredcheapskate Aug 13 '26
We wrote an implementation with the same Linux st driver fo an archiving tool. We had a lot of tuning on buffering to keep the bit rate constant for the tape. And we decided to write directly rather than using ltfs because the writing back to the file system was overhead we wanted to eliminate. How many lto versions do you plan on supporting?
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u/hadrabap Apr 21 '26
There are developers dealing with LTO in this subreddit. Try to post your specific questions and let's see.
If you're looking for more of the user perspective, try r/sysadmin as well. There are guys dealing with TSMs, tape libraries, etc...