5 ms·

Isn't that "base-10"? HDDs, RAM, network speed were base-2 (e.g. 1TB = 1024GB) for most of my life until SSDs became common and even Google now says "1 Gigabyt

by jotm 4y ago

Isn't that "base-10"? HDDs, RAM, network speed were base-2 (e.g. 1TB = 1024GB) for most of my life until SSDs became common and even Google now says "1 Gigabyte = 1000 Megabytes" to my exasperation.

cyberge99 4y ago
Technically it’s gibibyte(s).
CorrectHorseBat 4y ago
AFAIK network and HDDs were always measured in si units, only RAM was measured in powers of 2.
- deleted 4y ago
  [deleted]
- microtonal 4y ago
  For hard drives it was complicated, since their size is a function of the number of cylinders, heads, and sectors. Since the sector size is normally 512 bytes, they were a multiple of that. See e.g. this table of old hard drives: https://www.computerhope.com/hdquantu.htm https://www.computerhope.com/hdquantu.htm E.g., if you take the Quantum Bigfoot 1.2 GB model: 2492 cylinders * 16 heads * 63 sectors * 512 bytes per sector = 1286111232 bytes The size it was sold as, is definitely closer GiB (as in power of two): 1.2 * 2*30 = 1288490189 With rounding, they could sell it as 1.3 GiB with the current marketing trick of using SI units. So the old branding strategy seems to have been: compute the size in bytes, then find a reasonably MiB or GiB value (powers of two).
  - kloch 4y ago
    The gap between SI prefixes and their base-2 approximations grows as sizes get larger. Before 1GB HDD’s the file system overhead was a much more dramatic effect so it didn’t really matter to consumers which prefix convention they used or how they rounded.
  - CorrectHorseBat 4y ago
    As I see it the GB numbers are powers of 1000 rounded down: 2492 * 16 * 63 * 512 / 1000 ^ 3 = 1.286111232 4092 * 16 * 63 * 512 / 1000 ^ 3 = 2.111864832 4994 * 16 * 63 * 512 / 1000 ^ 3 = 2.577383424 Using GiB you get different numbers if you look past the first element in the table: 2492 * 16 * 63 * 512 / 1024 ^ 3 = 1.197784423828125 4092 * 16 * 63 * 512 / 1024 ^ 3 = 1.966827392578125 4994 * 16* 63 * 512 / 1024 ^ 3 = 2.4003753662109375 So I stand by my point, they have always used SI units. It's only ram (and software) that used incorrect definitions of k, M, G and T.
  - mlyle 4y ago
    The whole power-of-10 thing for storage goes back forever-- to IBM mainframes and to the first hard drives used in PCs. E.g. Seagate ST-506, first 5.25" hard drive. "The total formatted capacity of the four heads and surfaces is 5/10 megabytes (32 sectors per track, 256 bytes per sector, 612/1224 tracks)." 612 * 32 * 256 = 5013504, or 5.01 megabytes or 4.78 mebibytes.
cesarb 4y ago
> HDDs, RAM, network speed were base-2 (e.g. 1TB = 1024GB) for most of my life No, network speeds are the exception in that they have always used base-10 for a long time. For example, the basic ISDN data rate of 64kbit/s is exactly 64000 bits/s (8000 samples of 8-bit PCM per second); a 9.6k modem is 9600 bits/s; a 10 megabit Ethernet link is 10000000 bits/s; and so on.

by jotm 4y ago

Isn't that "base-10"? HDDs, RAM, network speed were base-2 (e.g. 1TB = 1024GB) for most of my life until SSDs became common and even Google now says "1 Gigabyte = 1000 Megabytes" to my exasperation.

cyberge99 4y ago

Technically it’s gibibyte(s).

CorrectHorseBat 4y ago

AFAIK network and HDDs were always measured in si units, only RAM was measured in powers of 2.

deleted 4y ago
[deleted]
microtonal 4y ago
For hard drives it was complicated, since their size is a function of the number of cylinders, heads, and sectors. Since the sector size is normally 512 bytes, they were a multiple of that. See e.g. this table of old hard drives: https://www.computerhope.com/hdquantu.htm https://www.computerhope.com/hdquantu.htm E.g., if you take the Quantum Bigfoot 1.2 GB model: 2492 cylinders * 16 heads * 63 sectors * 512 bytes per sector = 1286111232 bytes The size it was sold as, is definitely closer GiB (as in power of two): 1.2 * 2*30 = 1288490189 With rounding, they could sell it as 1.3 GiB with the current marketing trick of using SI units. So the old branding strategy seems to have been: compute the size in bytes, then find a reasonably MiB or GiB value (powers of two).
- kloch 4y ago
  The gap between SI prefixes and their base-2 approximations grows as sizes get larger. Before 1GB HDD’s the file system overhead was a much more dramatic effect so it didn’t really matter to consumers which prefix convention they used or how they rounded.
- CorrectHorseBat 4y ago
  As I see it the GB numbers are powers of 1000 rounded down: 2492 * 16 * 63 * 512 / 1000 ^ 3 = 1.286111232 4092 * 16 * 63 * 512 / 1000 ^ 3 = 2.111864832 4994 * 16 * 63 * 512 / 1000 ^ 3 = 2.577383424 Using GiB you get different numbers if you look past the first element in the table: 2492 * 16 * 63 * 512 / 1024 ^ 3 = 1.197784423828125 4092 * 16 * 63 * 512 / 1024 ^ 3 = 1.966827392578125 4994 * 16* 63 * 512 / 1024 ^ 3 = 2.4003753662109375 So I stand by my point, they have always used SI units. It's only ram (and software) that used incorrect definitions of k, M, G and T.
- mlyle 4y ago
  The whole power-of-10 thing for storage goes back forever-- to IBM mainframes and to the first hard drives used in PCs. E.g. Seagate ST-506, first 5.25" hard drive. "The total formatted capacity of the four heads and surfaces is 5/10 megabytes (32 sectors per track, 256 bytes per sector, 612/1224 tracks)." 612 * 32 * 256 = 5013504, or 5.01 megabytes or 4.78 mebibytes.

cesarb 4y ago

> HDDs, RAM, network speed were base-2 (e.g. 1TB = 1024GB) for most of my life No, network speeds are the exception in that they have always used base-10 for a long time. For example, the basic ISDN data rate of 64kbit/s is exactly 64000 bits/s (8000 samples of 8-bit PCM per second); a 9.6k modem is 9600 bits/s; a 10 megabit Ethernet link is 10000000 bits/s; and so on.