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Comment by m0lecules | Hacker News Reader

Why can't tape be self-contained like HDDs?

Aside from the fact that most people using tape for archival storage don't want to pay extra for the read/write heads, SATA interface, etc., there is no reason why you couldn't package all these things into a self-contained tape unit with a small flash disk acting as a small cache and directory listing.

You could definitely package such a thing for consumers, for example, but most workloads there aren't a great fit for the medium. Basically the only thing that makes sense is using it for archival and backups.

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> Why can't tape be self-contained like HDDs?

Because that gets rid of the main advantage of tape. Which is that the tape-media has no read/write head and is therefore much much much cheaper to mass produce.

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In practice, people buy tape-libraries entirely. Like a 3U unit with 50-tape slots + a few drives to read/write to those tapes, and then hook them up to the network.

https://www.quantum.com/en/products/tape-storage/

From this perspective, you buy as many tapes as you want storage (aiming for 500TB? Buy like 40 LTO7 tapes for your library. Aiming for 1000TB? Buy 80 LTO7 tapes for your library, assuming compression of course).

From there, you just read/write to the library, and have the underlying software handle the details, like any other NAS.

> assuming compression of course

I don't know why this seems the standard practice in the industry, but it really annoyed me when I realized a “15TB” LTO-7 tape has actually only 6TB real, “native” storage coz it assumes some average compression ratio.

Why is this acceptable? What if I use the tape to store incompressible data like video and images? Feels like intentional cheating.

Meh. It's only cheating if the manufacturer keeps it a secret, and they don't.

When a company is spending >$20k on a tape system, the people in charge of buying it will talk to the sales people, tell them the use case, and get a more accurate estimate.

If the buyers are engineers that understand the concept of storage space measured in bytes, this 'estimate' does not help them. If they don't, it only serves to mislead.

The fact that buyers may talk to salespeople is really not an excuse for the deceptive behavior.

"well, in our restaurant medium rare means well done and rare means medium rare, but that's okay our customers are well-paid professionals, they'll talk to waiters to get a more accurate picture"

Tangent: That's how most restaurants operate, because most people don't know what the words mean and get upset when they ask for "rare" and get what they asked for.

Clothing manufactures also lie about the waist measurements of pants. (Go measure yours and see.)

Funnily enough the first hard drives were like this too. They were a round pizza-sized (but a few inches thick) replaceable cartridge and could be inserted into a 'reader' which contained the heads.

But I guess work the data density required these days and the extreme closeness of the head to the platters this won't work anymore as dust would get in.

But this is how the first hard drives worked, we had some with our pdp-11 at the computer museum.

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