5 ms·

Technically HDD manufacturers are doing exactly the same.

by heavenlyblue 7y ago

Stratoscope 7y ago
Can you explain what you mean?
- gugagore 7y ago
  HDD manufactures often report a storage capacity that is larger than the effective capacity, since some capacity is used for formatting information, or error correction. This is the same situation with protocols (like gigabit Ethernet). There's also "punning" between the SI préfixes, where e.g. "kilo" can be used to mean 1000 or 1024. See https://en.m.wikipedia.org/wiki/Kibibyte https://en.m.wikipedia.org/wiki/Kibibyte
  - Dylan16807 7y ago
    Your second line is right. Your first isn't really. Formatting only reserves about 100MB. Error correction bits are completely hidden and not marketed at all. It's the 10% difference between "TB" and "TB" that really matters.
  - Stratoscope 7y ago
    I think modern HDD and SSD manufacturers have been pretty honest about the actual capacity of their drives. They have no way of knowing what kind of filesystem you will be putting on the drive and how much overhead it has, or whether you might be putting it in a RAID 1 array (which cuts the effective capacity per drive according to the number of drives in the array). The number of bytes they specify is the actual number of bytes available to your operating system. It seems like a pretty fair measurement. The 1000 vs. 1024 thing is an unfortunate point of confusion. Terms like kibibyte and such were an attempt to solve it, but they never took off. (If you were to ask me which number a kilobyte or kibibyte was, I would have to go look it up!) Even if we did use the kilo vs. kibi terms, HDD and SSD manufacturers are the ones who are getting it right. As the article you linked notes: > 1 kibibyte (KiB) = 2^10 bytes = 1024 bytes > The kibibyte is closely related to the kilobyte. The latter term is often used in some contexts as a synonym for kibibyte, but formally refers to 10^3 bytes = 1000 bytes, as the prefix kilo is defined in the International System of Units. The same applies as you go up in the units. One mega-anything is 1,000,000 of those things, giga- is 1,000,000,000, and tera- is 1,000,000,000,000 things. So a one-terabyte HDD or SSD should have a true capacity of 1,000,000,000,000 bytes, before any operating system or RAID overhead. Of course its actual physical capacity has to be higher, to support remapping of failing sectors or flash blocks and such. But that's all hidden by the drive controller. I think it's the memory people who got this wrong, by co-opting a "kilobyte" to mean 1024 bytes, contrary to the standard definition. It was a handy coincidence of terminology at the time, but the error was amplified as we got into multiples of that size. And then the operating system and utility people (or many of them) completely messed up by using the power-of-two definitions for disk/flash storage instead of the correct power-of-ten definitions. This is why, for example, every single Amazon listing of a 1TB drive (HDD, SSD, flash card) which honestly provides the correct 1,000,000,000,000 bytes of storage to the OS will have at least one review complaining: > Claims to have 1TB but only has 931GB as reported by my operating system. The "missing" 69GB isn't due to formatting or any misdoing on the part of the drive manufacturer, it's because the OS is using the wrong units.
    - Dylan16807 7y ago
      > Even if we did use the kilo vs. kibi terms, HDD and SSD manufacturers are the ones who are getting it right. I'd remove that "even". If we used both terms, then they'd be getting it right. But since we're not, they're being misleading compared to the typical use. > I think it's the memory people who got this wrong The memory people? It's pretty much everyone that uses "gigabyte" and isn't selling you a storage device.
    - planteen 7y ago
      Many Linux utilities do things with the kibi terms, using the MiB, GiB, TiB units. There have been a few lawsuits about this: https://en.wikipedia.org/wiki/Binary_prefix#Consumer_confusion https://en.wikipedia.org/wiki/Binary_prefix#Consumer_confusi... The outcome is that hard drive manufacturers need to explicitly print their definition of a "gigabyte". IMHO, it's not a right or wrong discussion, just a difference.
- blihp 7y ago
  The age old usable capacity complaint. (i.e. a 1TB drive will never actually give you 1TB of usable space)
- AdrianB1 7y ago
  Some people use decimal prefixes but they mean the binary values, for example kilo is 1000 but in computers is most often used as 1024. HDD manufacturers express the size in decimal (1 TB = 10^12 bytes), people that think in 1024 multiples will calculate this is less Gigabytes than expected.
- bluedino 7y ago
  1GB RAM > 1GB HDD
mrb 7y ago
I never understood why specifically HDD manufacturers are criticized when in fact all vendors and all types of hardware (expect RAM) follow the same convention of using decimal prefixes: http://blog.zorinaq.com/decimal-prefixes-are-more-common-than-binary-prefixes-in-the-com/ http://blog.zorinaq.com/decimal-prefixes-are-more-common-tha...
aaronmdjones 7y ago
I see this repeated time and time again, and every time it isn't true. This is what my console shows when it sees a 1 TB drive: [ 1.629496] sd 2:0:0:0: [sda] 1953525168 512-byte logical blocks: (1.00 TB/932 GiB) If you multiply those 2 numbers (1953525168 x 512 bytes), you arrive at 1000204886000 bytes, or 1000.204886 GB. You can write to every single one of those bytes/sectors, none of them are reserved. Your choice of filesystem dictates the maximum amount of space you can use on the drive, but the drive itself is giving you all of the capacity you asked for, and if you don't use any filesystem at all, you can write 1TB to it. The confusion comes from Microsoft Windows being involved. Windows measures in IEC units, but displays the value as an SI unit. So, for example, it will tell you that a 16000000-byte file is 15.26 MB. It isn't. It's 16 MB; it is also 15.26 MiB. Likewise, Windows will tell you that a 1 TB harddrive is 931 GB. It isn't, it's 1000 GB; it is also 931 GiB. If I'm a cable vendor, and you ask me for a reel of 8 kilometres of cable, and I give you a 5-mile reel, I gave you what you asked for. 5 is less than 8, but 5 miles is not less than 8 kilometres. 931 is less than 1000, but 931 GiB is not less than 1000 GB.
- Dylan16807 7y ago
  > I see this repeated time and time again, and every time it isn't true. What isn't true? That they're using a definition that's technically correct but doesn't align with the lay definitions of the units? I don't think you can call that untrue, no matter how prescriptivist you get. And it's worse than that, because other technical users also mean powers of 2^10. And it goes far beyond Windows, and has nothing to do with file systems.
  - kube-system 7y ago
    Gibibyte is not a different definition of gigabyte. They’re different units.
    - lostlogin 7y ago
      On reading this on iOS I selected the word and pressed “look up”. It seems that iOS strips out formatting in its dictionary, make superscript full size. Not ideal. Gigabyte “a unit of information equal to one thousand million (109) or, strictly, 230 bytes.”
taneq 7y ago
Technically, everyone in computing BUT the HDD manufacturers are doing this. That's why we now have MiB, GiB etc. units as well as MB, GB etc.

Technically HDD manufacturers are doing exactly the same.

Stratoscope 7y ago

Can you explain what you mean?

gugagore 7y ago
HDD manufactures often report a storage capacity that is larger than the effective capacity, since some capacity is used for formatting information, or error correction. This is the same situation with protocols (like gigabit Ethernet). There's also "punning" between the SI préfixes, where e.g. "kilo" can be used to mean 1000 or 1024. See https://en.m.wikipedia.org/wiki/Kibibyte https://en.m.wikipedia.org/wiki/Kibibyte
- Dylan16807 7y ago
  Your second line is right. Your first isn't really. Formatting only reserves about 100MB. Error correction bits are completely hidden and not marketed at all. It's the 10% difference between "TB" and "TB" that really matters.
- Stratoscope 7y ago
  I think modern HDD and SSD manufacturers have been pretty honest about the actual capacity of their drives. They have no way of knowing what kind of filesystem you will be putting on the drive and how much overhead it has, or whether you might be putting it in a RAID 1 array (which cuts the effective capacity per drive according to the number of drives in the array). The number of bytes they specify is the actual number of bytes available to your operating system. It seems like a pretty fair measurement. The 1000 vs. 1024 thing is an unfortunate point of confusion. Terms like kibibyte and such were an attempt to solve it, but they never took off. (If you were to ask me which number a kilobyte or kibibyte was, I would have to go look it up!) Even if we did use the kilo vs. kibi terms, HDD and SSD manufacturers are the ones who are getting it right. As the article you linked notes: > 1 kibibyte (KiB) = 2^10 bytes = 1024 bytes > The kibibyte is closely related to the kilobyte. The latter term is often used in some contexts as a synonym for kibibyte, but formally refers to 10^3 bytes = 1000 bytes, as the prefix kilo is defined in the International System of Units. The same applies as you go up in the units. One mega-anything is 1,000,000 of those things, giga- is 1,000,000,000, and tera- is 1,000,000,000,000 things. So a one-terabyte HDD or SSD should have a true capacity of 1,000,000,000,000 bytes, before any operating system or RAID overhead. Of course its actual physical capacity has to be higher, to support remapping of failing sectors or flash blocks and such. But that's all hidden by the drive controller. I think it's the memory people who got this wrong, by co-opting a "kilobyte" to mean 1024 bytes, contrary to the standard definition. It was a handy coincidence of terminology at the time, but the error was amplified as we got into multiples of that size. And then the operating system and utility people (or many of them) completely messed up by using the power-of-two definitions for disk/flash storage instead of the correct power-of-ten definitions. This is why, for example, every single Amazon listing of a 1TB drive (HDD, SSD, flash card) which honestly provides the correct 1,000,000,000,000 bytes of storage to the OS will have at least one review complaining: > Claims to have 1TB but only has 931GB as reported by my operating system. The "missing" 69GB isn't due to formatting or any misdoing on the part of the drive manufacturer, it's because the OS is using the wrong units.
  - Dylan16807 7y ago
    > Even if we did use the kilo vs. kibi terms, HDD and SSD manufacturers are the ones who are getting it right. I'd remove that "even". If we used both terms, then they'd be getting it right. But since we're not, they're being misleading compared to the typical use. > I think it's the memory people who got this wrong The memory people? It's pretty much everyone that uses "gigabyte" and isn't selling you a storage device.
  - planteen 7y ago
    Many Linux utilities do things with the kibi terms, using the MiB, GiB, TiB units. There have been a few lawsuits about this: https://en.wikipedia.org/wiki/Binary_prefix#Consumer_confusion https://en.wikipedia.org/wiki/Binary_prefix#Consumer_confusi... The outcome is that hard drive manufacturers need to explicitly print their definition of a "gigabyte". IMHO, it's not a right or wrong discussion, just a difference.
blihp 7y ago
The age old usable capacity complaint. (i.e. a 1TB drive will never actually give you 1TB of usable space)
AdrianB1 7y ago
Some people use decimal prefixes but they mean the binary values, for example kilo is 1000 but in computers is most often used as 1024. HDD manufacturers express the size in decimal (1 TB = 10^12 bytes), people that think in 1024 multiples will calculate this is less Gigabytes than expected.
bluedino 7y ago
1GB RAM > 1GB HDD

mrb 7y ago

I never understood why specifically HDD manufacturers are criticized when in fact all vendors and all types of hardware (expect RAM) follow the same convention of using decimal prefixes: http://blog.zorinaq.com/decimal-prefixes-are-more-common-than-binary-prefixes-in-the-com/ http://blog.zorinaq.com/decimal-prefixes-are-more-common-tha...

aaronmdjones 7y ago

I see this repeated time and time again, and every time it isn't true. This is what my console shows when it sees a 1 TB drive: [ 1.629496] sd 2:0:0:0: [sda] 1953525168 512-byte logical blocks: (1.00 TB/932 GiB) If you multiply those 2 numbers (1953525168 x 512 bytes), you arrive at 1000204886000 bytes, or 1000.204886 GB. You can write to every single one of those bytes/sectors, none of them are reserved. Your choice of filesystem dictates the maximum amount of space you can use on the drive, but the drive itself is giving you all of the capacity you asked for, and if you don't use any filesystem at all, you can write 1TB to it. The confusion comes from Microsoft Windows being involved. Windows measures in IEC units, but displays the value as an SI unit. So, for example, it will tell you that a 16000000-byte file is 15.26 MB. It isn't. It's 16 MB; it is also 15.26 MiB. Likewise, Windows will tell you that a 1 TB harddrive is 931 GB. It isn't, it's 1000 GB; it is also 931 GiB. If I'm a cable vendor, and you ask me for a reel of 8 kilometres of cable, and I give you a 5-mile reel, I gave you what you asked for. 5 is less than 8, but 5 miles is not less than 8 kilometres. 931 is less than 1000, but 931 GiB is not less than 1000 GB.

Dylan16807 7y ago
> I see this repeated time and time again, and every time it isn't true. What isn't true? That they're using a definition that's technically correct but doesn't align with the lay definitions of the units? I don't think you can call that untrue, no matter how prescriptivist you get. And it's worse than that, because other technical users also mean powers of 2^10. And it goes far beyond Windows, and has nothing to do with file systems.
- kube-system 7y ago
  Gibibyte is not a different definition of gigabyte. They’re different units.
  - lostlogin 7y ago
    On reading this on iOS I selected the word and pressed “look up”. It seems that iOS strips out formatting in its dictionary, make superscript full size. Not ideal. Gigabyte “a unit of information equal to one thousand million (109) or, strictly, 230 bytes.”

taneq 7y ago

Technically, everyone in computing BUT the HDD manufacturers are doing this. That's why we now have MiB, GiB etc. units as well as MB, GB etc.