6 ms·

Magnetic tape have simply a far bigger working area than HDDs. An HDD have only it's disk area, multiplied by the number of disks. Magnetic tape is wrapped

by Kuinox 5y ago

Magnetic tape have simply a far bigger working area than HDDs. An HDD have only it's disk area, multiplied by the number of disks. Magnetic tape is wrapped which make the total surface way way higher.

Dylan16807 5y ago
Not "simply" when the densities are so different. They both happen to be similar in price, but if the density gap grew by 3x then suddenly tape would be more expensive and only used for certain types of archival.
- Kuinox 5y ago
  The areal density of tape is far lower, but the volume density is higher, simply because HDDs plays only on 2D planes while tapes are wrapped. If the density gap grew, magnetics tapes will try to put more tape in a single enclosure, like HDDs try to put more disk in a single enclosure.
  - Dylan16807 5y ago
    > the volume density is higher Not really. If you compare the current best tapes and hard drives, the hard drives store exactly the same amount per cubic centimeter. If you look at just the 10cm by 10cm part with the platters, and compare it to the 10cm by 10cm tape cartridge, the hard drive is fitting more data into less space. Once LTO-9 is available then it will win the first comparison but it will be just about tied for the second comparison. > If the density gap grew, magnetics tapes will try to put more tape in a single enclosure, like HDDs try to put more disk in a single enclosure. You can only fit so much more tape in the same box. They've already been increasing the tape length as much as is reasonable, but from LTO-3 to LTO-9 it's less than a 50% increase. Much like hard drives have managed to fit in a couple extra platters.
    - adrian_b 5y ago
      What really counts is the volume density for the entire device, i.e. for a LTO tape cartridge vs. a 3.5" HDD. Comparing a 12 TB tape with an 18 TB 3.5" HDD, the volume of the cartridge is about a half or less, so the tape still has better density. Moreover the tape cartridge is many times lighter, if you carry in your pocket a tape cartridge vs a 3.5" HDD, the difference is very significant. You would not notice the tape cartridge, while the HDD would be like having a stone in your pocket. Experimental tapes have already been demonstrated at volumic densities much better than what HDDs hope to achieve in the future.
      - Dylan16807 5y ago
        > Comparing a 12 TB tape with an 18 TB 3.5" HDD, the volume of the cartridge is about a half or less, so the tape still has better density. The volume of a tape is very close to 60% of a hard drive. So 12TB tape and 20TB drive are very close. If we use 18TB then it's still close. But I wasn't even making an argument about the current tech. I was talking about if things were nudged just a bit. If we go back to imagining the world where the huge areal density gap is made slightly larger, then hard drives would crush tapes in both price and density. Despite tapes having a far bigger working area. So the analysis is not "simply" that tapes have a far bigger working area. If it was, we'd have hundreds of terabytes in a tape right now. > Moreover the tape cartridge is many times lighter, if you carry in your pocket a tape cartridge vs a 3.5" HDD, the difference is very significant. You would not notice the tape cartridge, while the HDD would be like having a stone in your pocket. That's such a niche use it would barely affect sales. Effectively nobody carries around pocket tapes, because if you can afford a drive then you have stacks and stacks of tapes. > Experimental tapes have already been demonstrated at volumic densities much better than what HDDs hope to achieve in the future. That's cool but I'll wait to see when/if they're practical to make into a product, and whether something else has come along to make both of them blush.
    - deleted 5y ago
      [deleted]

by Kuinox 5y ago

Dylan16807 5y ago

Not "simply" when the densities are so different. They both happen to be similar in price, but if the density gap grew by 3x then suddenly tape would be more expensive and only used for certain types of archival.

Kuinox 5y ago
The areal density of tape is far lower, but the volume density is higher, simply because HDDs plays only on 2D planes while tapes are wrapped. If the density gap grew, magnetics tapes will try to put more tape in a single enclosure, like HDDs try to put more disk in a single enclosure.
- Dylan16807 5y ago
  > the volume density is higher Not really. If you compare the current best tapes and hard drives, the hard drives store exactly the same amount per cubic centimeter. If you look at just the 10cm by 10cm part with the platters, and compare it to the 10cm by 10cm tape cartridge, the hard drive is fitting more data into less space. Once LTO-9 is available then it will win the first comparison but it will be just about tied for the second comparison. > If the density gap grew, magnetics tapes will try to put more tape in a single enclosure, like HDDs try to put more disk in a single enclosure. You can only fit so much more tape in the same box. They've already been increasing the tape length as much as is reasonable, but from LTO-3 to LTO-9 it's less than a 50% increase. Much like hard drives have managed to fit in a couple extra platters.
  - adrian_b 5y ago
    What really counts is the volume density for the entire device, i.e. for a LTO tape cartridge vs. a 3.5" HDD. Comparing a 12 TB tape with an 18 TB 3.5" HDD, the volume of the cartridge is about a half or less, so the tape still has better density. Moreover the tape cartridge is many times lighter, if you carry in your pocket a tape cartridge vs a 3.5" HDD, the difference is very significant. You would not notice the tape cartridge, while the HDD would be like having a stone in your pocket. Experimental tapes have already been demonstrated at volumic densities much better than what HDDs hope to achieve in the future.
    - Dylan16807 5y ago
      > Comparing a 12 TB tape with an 18 TB 3.5" HDD, the volume of the cartridge is about a half or less, so the tape still has better density. The volume of a tape is very close to 60% of a hard drive. So 12TB tape and 20TB drive are very close. If we use 18TB then it's still close. But I wasn't even making an argument about the current tech. I was talking about if things were nudged just a bit. If we go back to imagining the world where the huge areal density gap is made slightly larger, then hard drives would crush tapes in both price and density. Despite tapes having a far bigger working area. So the analysis is not "simply" that tapes have a far bigger working area. If it was, we'd have hundreds of terabytes in a tape right now. > Moreover the tape cartridge is many times lighter, if you carry in your pocket a tape cartridge vs a 3.5" HDD, the difference is very significant. You would not notice the tape cartridge, while the HDD would be like having a stone in your pocket. That's such a niche use it would barely affect sales. Effectively nobody carries around pocket tapes, because if you can afford a drive then you have stacks and stacks of tapes. > Experimental tapes have already been demonstrated at volumic densities much better than what HDDs hope to achieve in the future. That's cool but I'll wait to see when/if they're practical to make into a product, and whether something else has come along to make both of them blush.
  - deleted 5y ago
    [deleted]