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Physically Immutable Optical Archive Libraries

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Re: Physically Immutable Optical Archive Libraries

#4
So it's like a tape library, but for 1Tb optical disks?

I think a tape library still wins. LTO-9 allows 18Tb on one tape (without compression) and LTO-10 is 30/40Tb

And tape is going to be fine, as long as it's kept in reasonable conditions. No need to do clean rooms to store it or anything like that.

Re: Physically Immutable Optical Archive Libraries

#5
post #4

So it's like a tape library, but for 1Tb optical disks? I think a tape library still wins. LTO-9 allows 18Tb on one tape (without compression) and LTO-10 is 30/40Tb And tape is going to be fine, as long as it's kept in reasonable conditions. No need to do clean rooms to store it or anything like that.

The tricky bit, especially for the small operater is keeping a working drive as long as you want to keep the storage.

Re: Physically Immutable Optical Archive Libraries

#7
With that modern LLMs are capable of I'n seriously considering investing in at least M-DISC storage or similar to store stuff I don't want to lose :). It's unlikely that both iCloud and Synology get hacked at the same time, but the probability is higher than I could imagine before.

Re: Physically Immutable Optical Archive Libraries

#8
post #5
post #4

So it's like a tape library, but for 1Tb optical disks? I think a tape library still wins. LTO-9 allows 18Tb on one tape (without compression) and LTO-10 is 30/40Tb And tape is going to be fine, as long as it's kept in reasonable conditions. No need to do clean rooms to store it or anything like that.

The tricky bit, especially for the small operater is keeping a working drive as long as you want to keep the storage.

Yeah, the back-compat story for LTOs is not great. They are going to try and improve it starting with LTO-10.

It was partially on purpose for the earlier LTO generations. The capacity/speed ratio was not too high, so you could just keep upgrading your library in the background every decade. It outweighed the complexity of designing backwards-compatible hardware.

But it's becoming less practical now. LTO-4 is 1.6Tb with 160Mb read speed, so each tape takes just about 3 hours to read. LTO-10 is 40Tb with 400Mb read speed, resulting in more than 24 hours of time to read one tape.

Drive availability is an interesting question in itself. Laser drivers are pretty complicated beasts themselves that require highly precise mechanics. Tape drives are much simpler, because the areal information density is about 3 orders of magnitude smaller than on optical media.

The mechanical stuff that loads and unloads the tape and keeps it in tension is crazy, but it's all just regular "macroscopic" parts that can be custom-manufactured if needed.

Re: Physically Immutable Optical Archive Libraries

#9
post #8
post #5

Earlier quoted context omitted.

The tricky bit, especially for the small operater is keeping a working drive as long as you want to keep the storage.

Yeah, the back-compat story for LTOs is not great. They are going to try and improve it starting with LTO-10. It was partially on purpose for the earlier LTO generations. The capacity/speed ratio was not too high, so you could just keep upgrading your library in the background every decade. It outweighed the complexity of designing backwards-compatible hardware. But it's becoming less practical now. LTO-4 is 1.6Tb wi…

> Tape drives are much simpler

Maybe back in the 90's :)

LTO-9 increased track density, increased the total number of tracks by reducing their width and increased linear density.

The "how" certainly does not sound "much simpler" to me ?[1]

    The new, narrower track width was achieved through a combination of improvements in tracking
    performance, new, narrower tunneling magnetoresistive (TMR) readers within the head assembly
    (now 
In addition the LTO Program's own technical paper describes how LTO-9 manages dimensional changes in the new substrate with a one-time-per-tape calibration algorithm to control 32-channel recording via closed-loop servo algorithms, plus a longer-block Reed-Solomon C2 code — together getting LTO-9's uncorrectable bit error rate to 10⁻²⁰, a 10× improvement over LTO-8[2]

[1] https://at.ingrammicro.eu/api/cfs/Icecat/PDF.ashx?l=en&s=957... [2] https://www.lto.org/wp-content/uploads/2022/08/LTO-UBER-Tech...

Re: Physically Immutable Optical Archive Libraries

#10

The video says they use 200GB Blu-ray media. Is this something new?

No. In fact, Sony had their own version of this that had three generations of media before getting shitcanned. I think it wound up going to something like 300GB discs - which is like 2.5x what consumers can do with BDXLs.
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