A Brief History of Data Storage - Eli Holderness - NDC London 2024

[@computertoucher]

Unless I’m missing something about what you meant, I’m a bit baffled to hear the claim that shingled recording on hard disks is a specialised thing reserved for long term cold storage, because that’s very much incorrect. Seagate has been quietly selling shingled (SMR, Shingled Magnetic Recording) HDDs for at least a decade now, which caused a fair bit of controversy due to the performance disadvantage you mentioned in this talk. (They were not, and still are not, especially transparent about specifying to the consumer whether a given drive uses CMR or SMR.) Aside from that detail, I enjoyed this quite a lot, thank you!

[@nintendoeats]

They may have been talking particularly about host-managed SMR. From a user perspective the seagate SMR disks are just like regular disks but with inconsistent performance (and support for the TRIM command). I assume that the drives used in cold storage facilities are host-managed SMR, where the computer can take more direct control over how the data is written (how this helps I have no idea, but it's a thing).

[@computertoucher]

@@nintendoeats Oh, maybe. Didn't actually say as much, if so, and it being stated generally makes it sound like ANY shingled drives are not sold to general consumers, which is obviously not the case. It would certainly make sense if you were correct about that though, because it strikes me as highly unlikely that somebody with a special interest in storage wouldn't know that SMR consumer drives have been not only in existence but extremely common for a decade at least.

[@nintendoeats]

@@computertoucher I agree, they didn't definitely didn't state it if that's what they meant.

[@edgeeffect]

Many of my favourites were missing from this talk, but if they'd included everything, it would have been about 6 hours long... which may have proved a little tiring.

[@urmet]

afaik CD is constant linear speed, slowing down angular speed when reading outer rings

[@vylbird8014]

For audio mode, correct. For data modes, it doesn't actually matter so long - some drives read CLV, mostly very old ones, while newer ones will run CAV and adapt for the different bit rate in the drives electronics. Data modes make no guarantee about seek times or sustained read speed, unlike audio.

[@computertoucher]

This was a thing LaserDisc changed its mind about a bit as well. CAV was generally considered better for a long time since it let you seek frame by frame (and there is arguably a small picture quality benefit) but once players started implementing field memory on the player side, CLV more or less took over, with CAV mostly being reserved as a “premium” format for special edition box sets and the like (since CLV let you fit much more on one disc).

[@nintendoeats]

@@vylbird8014 I think the important thing is that the data is CLV. As you say, whether the drive reads it in a CAV or CLV matter is not dictated by the design of the format.