Re:Western Digital is trying to redefine the word “RPM”
by userbinator on Monday September 07, 2020 @10:07PM
(#24404641)
In 1962 an ACM paper referred to a "4K IBM 1401" which had 4000 characters of storage, but in 1964 Amdahl wrote a paper that had 1K meaning 1024.
That's easy to explain, as a 1401 is actually a decimal computer.
Re:Western Digital is trying to redefine the word “RPM”
by throw0101a on Tuesday September 08, 2020 @10:45AM
(#24408905)
Further up:
> In the 1950s, "1 kilobit" meant 1000 bits:[9][10]
Re:Western Digital is trying to redefine the word “RPM”
by ATsch on Tuesday September 08, 2020 @03:41AM
(#24406087)
It just randomly so happened that drive manufacturers used the meaning that benefitted them and is not really used by anyone else
Re:Western Digital is trying to redefine the word “RPM”
by throw0101a on Tuesday September 08, 2020 @10:44AM
(#24408888)
It just randomly so happened that drive manufacturers used the meaning of what the SI folks said the meaning actually was.
Re:Western Digital is trying to redefine the word “RPM”
by boomboomsubban on Tuesday September 08, 2020 @03:19PM
(#24411948)
While I'll admit they do have a slightly better case here, basically every OS's definition is more important than the SI. They clearly did it to make their drives look bigger. As proof, why are they sticking behind old SI definitions 25 years after they added the other ones?
Re:Western Digital is trying to redefine the word “RPM”
by throw0101a on Tuesday September 08, 2020 @07:52PM
(#24415009)
> As proof, why are they sticking behind old SI definitions 25 years after they added the other ones?
Because hard drives, going back to the original (the IBM 350), have used decimal prefixes.
Re:Western Digital is trying to redefine the word “RPM”
by boomboomsubban on Tuesday September 08, 2020 @09:09PM
(#24415588)
At best, that means they should have switched when SSD's happened.
Given what this article is about, I don't know why you're giving HD manufacturers the benefit of the doubt.
The 'confusion' as to whether the "K" prefix meant a factor of 10^3 or 2^10 goes back decades.
In 1961 a book says "it is more usual to express the speed in bits or kilobits (1,000 bits) per second"; an IBM 1410 manual says ""The 40K core array requires 40,000 valid five-position addresses from 0,000 to 39,999." In 1962 an ACM paper referred to a "4K IBM 1401" which had 4000 characters of storage, but in 1964 Amdahl wrote a paper that had 1K meaning 1024. Academics went back and forth a bit it seems.
* https://en.wikipedia.org/wiki/Timeline_of_binary_prefixes
For hard drives specifically, a 1974 example has Mbytes in the 10^6 sense. Further examples often have drives using the base-10 sense of the prefix (including the first 5 ¼ inch floppy), while memory chips using the base-2 sense of the prefix.
The powers-of-1024 nomenclature of kibi/mebi/etc was introduced in 1995, with IEEE mandating SI prefixes only be used for powers-of-1000 in 1997. The IEC follows suit a couple of years later.
* https://en.wikipedia.org/wiki/Binary_prefix