Re: PROBLEM: KB->KiB, MB -> MiB, ... (IEC 60027-2)
> "Jan" == Jan Engelhardt <[EMAIL PROTECTED]> writes: Jan> For "F"s sake, when you gotta use abbreviations, then just use Jan> k=1000 and K=1024 already, b for bits and B for bytes. Problem Jan> gone. The one-letter abbreviations are identical to SI prefixes, except for "K", which is used interchangeably with "k" (in SI, "K" stands for the kelvin, and only "k" stands for 1,000). [...] BIPM (which maintains SI) expressly prohibits the binary prefix usage, and recommends the use of the IEC prefixes as an alternative (computing units are not included in SI). Some have suggested that "k" be used for 1,000, and "K" for 1,024, but this cannot be extended to the higher order prefixes and has never been widely recognised. -- http://en.wikipedia.org/wiki/Binary_prefix So if you continue insisting that "MB" is really 2^20 bytes, you're flouting the SI in at least two ways. I'd expect that from an USAian, not a German. ;-> (To be clear, I *am* a USAian, and I really desperately wish this country were metric...) Some other gems from that article that haven't been covered in this thread: * CD-Rs are generally specified in MiB, but DVD-Rs in GB * CPU clocks are given in decimal (See http://en.wikipedia.org/wiki/Binary_prefix#Usage_notes ) It also points out that there are some ongoing lawsuits on exactly this topic, completely analogous to the CRT diagonal cases. > "Alan" == Alan Cox <[EMAIL PROTECTED]> writes: Alan> K is Kelvin, k is kilo- One nice thing about IEC 60027-2 is that it seems to have fixed the capitalization inconsistency; kibi- really is "Ki". (I never cared for the lower-case "k" for "kilo-"; there are other clashes of symbols in the SI system proper; think "milli-" and "meter".) The standard also specifically states that "B", when used with the binary prefixes, is "byte" not "Bel". Which is nice. t. - To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to [EMAIL PROTECTED] More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
Re: PROBLEM: KB-KiB, MB - MiB, ... (IEC 60027-2)
Jan == Jan Engelhardt [EMAIL PROTECTED] writes: Jan For Fs sake, when you gotta use abbreviations, then just use Jan k=1000 and K=1024 already, b for bits and B for bytes. Problem Jan gone. The one-letter abbreviations are identical to SI prefixes, except for K, which is used interchangeably with k (in SI, K stands for the kelvin, and only k stands for 1,000). [...] BIPM (which maintains SI) expressly prohibits the binary prefix usage, and recommends the use of the IEC prefixes as an alternative (computing units are not included in SI). Some have suggested that k be used for 1,000, and K for 1,024, but this cannot be extended to the higher order prefixes and has never been widely recognised. -- http://en.wikipedia.org/wiki/Binary_prefix So if you continue insisting that MB is really 2^20 bytes, you're flouting the SI in at least two ways. I'd expect that from an USAian, not a German. ;- (To be clear, I *am* a USAian, and I really desperately wish this country were metric...) Some other gems from that article that haven't been covered in this thread: * CD-Rs are generally specified in MiB, but DVD-Rs in GB * CPU clocks are given in decimal (See http://en.wikipedia.org/wiki/Binary_prefix#Usage_notes ) It also points out that there are some ongoing lawsuits on exactly this topic, completely analogous to the CRT diagonal cases. Alan == Alan Cox [EMAIL PROTECTED] writes: Alan K is Kelvin, k is kilo- One nice thing about IEC 60027-2 is that it seems to have fixed the capitalization inconsistency; kibi- really is Ki. (I never cared for the lower-case k for kilo-; there are other clashes of symbols in the SI system proper; think milli- and meter.) The standard also specifically states that B, when used with the binary prefixes, is byte not Bel. Which is nice. t. - To unsubscribe from this list: send the line unsubscribe linux-kernel in the body of a message to [EMAIL PROTECTED] More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
Re: PROBLEM: KB->KiB, MB -> MiB, ... (IEC 60027-2)
>>>>> "Tony" == Tony Foiani <[EMAIL PROTECTED]> writes: Tony> How fast is your Ethernet port? 100Mbps or 95.37Mbps? >>>>> "Jan" == Jan Engelhardt <[EMAIL PROTECTED]> writes: Jan> Same lie like with harddrives. It's around 80, not 100. But it Jan> depends on how you look at it. 80 for Layer3, possibly a little Jan> more for Layer2/1. No, it's not the same lie. The physical media -- as presented to the next higher layer -- really has 100Mbps capability. Likewise, the "physical media" of a hard drive (as seen outside the controller on the disk) really is 500GB/465GiB (or whatever). [1] The overhead caused by Ethernet frames (level 2) and then IP packets (level 3) and then TCP or UDP (level 4) are more closely related to the losses you get on filesystem overhead (superblock, inodes, directories) and "slack" in block-allocated systems (having to round sizes up to the next 512 or whatever). [2] The problem is that a drive labelled "500GB" on its packaging is displayed as "465GB" on the computer. The fix is to have the computer display either "500GB" or "465GiB". t. [1] SFAIK, what's really on hard drive platters anymore is something much closer to "symbols", not just 1s and 0s. In the same way that "baud" is "symbols per second", the actual thingies on the platters are symbols, and it's up to the drive electronics to make sense of them. [2] Level numbers from: http://en.wikipedia.org/wiki/TCP/IP_model - To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to [EMAIL PROTECTED] More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
Re: PROBLEM: KB-KiB, MB - MiB, ... (IEC 60027-2)
Tony == Tony Foiani [EMAIL PROTECTED] writes: Tony How fast is your Ethernet port? 100Mbps or 95.37Mbps? Jan == Jan Engelhardt [EMAIL PROTECTED] writes: Jan Same lie like with harddrives. It's around 80, not 100. But it Jan depends on how you look at it. 80 for Layer3, possibly a little Jan more for Layer2/1. No, it's not the same lie. The physical media -- as presented to the next higher layer -- really has 100Mbps capability. Likewise, the physical media of a hard drive (as seen outside the controller on the disk) really is 500GB/465GiB (or whatever). [1] The overhead caused by Ethernet frames (level 2) and then IP packets (level 3) and then TCP or UDP (level 4) are more closely related to the losses you get on filesystem overhead (superblock, inodes, directories) and slack in block-allocated systems (having to round sizes up to the next 512 or whatever). [2] The problem is that a drive labelled 500GB on its packaging is displayed as 465GB on the computer. The fix is to have the computer display either 500GB or 465GiB. t. [1] SFAIK, what's really on hard drive platters anymore is something much closer to symbols, not just 1s and 0s. In the same way that baud is symbols per second, the actual thingies on the platters are symbols, and it's up to the drive electronics to make sense of them. [2] Level numbers from: http://en.wikipedia.org/wiki/TCP/IP_model - To unsubscribe from this list: send the line unsubscribe linux-kernel in the body of a message to [EMAIL PROTECTED] More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
Re: PROBLEM: KB->KiB, MB -> MiB, ... (IEC 60027-2)
> "David" == David Schwartz <[EMAIL PROTECTED]> writes: David> The way RAM and flash are measured is correct. In my experience, RAM and flash *drives* are measured differently. I understand that individual flash chips come in powers of 2, but by the time they're packaged as a "flash drive", some of that has been used up -- yet they're still sold as the full capacity, and the manufacturers use the confusion between MiB and MB to defend the practice. This "16Mb" drive doesn't really have 16 megabytes of capacity - it's really got 15.5. But that's just standard operating procedure for storage manufacturers. Non-volatile storage manufacturers, including hard drive companies, like to define a megabyte as 1,000,000 bytes and a gigabyte as 1,000,000,000 bytes. They're actually two-to-the-power-of-20 and two-to-the-power-of-30 bytes, which is 1,048,576 and 1,073,741,824 bytes respectively. This is the main reason why a "20Gb" hard drive won't actually give you 20Gb of capacity. In flash RAM devices, things can get a bit more complex again, thanks to the small amount of memory which may be used by the device itself for housekeeping. That can vary between device families; a CompactFlash card with a given nominal capacity may actually have a bit less space than a SmartMedia card with the same number on the label. And manufacturers may throw in some more memory to push the real capacity up closer to the stated one, which is what they've done with the USBDrive. It's still about three per cent shy of its claimed capacity, though. -- http://www.dansdata.com/flashcomp.htm (E.g., my "512MB" CF card shows up as "487MB" in the camera -- a difference of exactly 5%, as would be expected by the MB-vs-MiB scam. I'd be happier if the camera said "487MiB", but we're looking at OSes we do have control over, not others.) And this cheat is getting better (for the seller) with every expansion: 1 MiB is 5% bigger than 1 MB 1 GiB is 7% bigger than 1 GB 1 TiB is 10% bigger than 1 TB So when you go out to buy your 1TB drive this year, you're really only buying 0.9TiB or so. Since all the manufacturers do the same thing, it's possible to consider it "fair", at least for comparisons -- but when the customer gets home and formats their drive, I think they'd be happier if the number was the same as on the carton. Just last night I formatted some new "500GB" drives, and they eventually came back with 465GB as the displayed capacity. Wouldn't it make more sense to display that as "465GiB"? David> Talk about a cure worse than the disease! So you're saying that David> 256MB flash cards could be advertised as having 268.4MB? A David> 512MB RAM stick is mislabelled and could correctly say 536.8MB? David> That's just plain craziness. No, it sounds like he wants them advertised as 256MB and 512MiB, respectively -- packaged flash cards tend to use the 1000 multiples, while DRAM uses the 1024. One extra letter doesn't sound all that crazy. How fast is your Ethernet port? 100Mbps or 95.37Mbps? Somewhat archaic now, but how big was your common 3.5" floppy disk (PC "HD" format)? It actually used a basis of 1,024,000: And if two definitions of the megabyte are not enough, a third megabyte of 1 024 000 bytes is the megabyte used to format the familiar 90 mm (3 1/2 inch), "1.44 MB" diskette. -- http://physics.nist.gov/cuu/Units/binary.html What's likely is that the flash and drive manufacturers will either mark their products honestly, or they'll increase the capacity of their product to meet the given label. (Think about the CRT "diagonal" measurements -- it took a few lawsuits, but they eventually switched from measuring bezel-to-bezel, or total tube diagonal, to "viewable". Sure, everyone in technology "knew" that you had to chop off an inch or two from the advertised value to get the viewable; but that's not enough to meet the standard of truth in advertising.) David> Adopting IEC 60027-2 just replaces a set of well-understood David> problems with all new problems. Which are clearly solved in the standards document, and remove any ambiguity. Is one extra character really that painful to you? t. - To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to [EMAIL PROTECTED] More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
Re: PROBLEM: KB-KiB, MB - MiB, ... (IEC 60027-2)
David == David Schwartz [EMAIL PROTECTED] writes: David The way RAM and flash are measured is correct. In my experience, RAM and flash *drives* are measured differently. I understand that individual flash chips come in powers of 2, but by the time they're packaged as a flash drive, some of that has been used up -- yet they're still sold as the full capacity, and the manufacturers use the confusion between MiB and MB to defend the practice. This 16Mb drive doesn't really have 16 megabytes of capacity - it's really got 15.5. But that's just standard operating procedure for storage manufacturers. Non-volatile storage manufacturers, including hard drive companies, like to define a megabyte as 1,000,000 bytes and a gigabyte as 1,000,000,000 bytes. They're actually two-to-the-power-of-20 and two-to-the-power-of-30 bytes, which is 1,048,576 and 1,073,741,824 bytes respectively. This is the main reason why a 20Gb hard drive won't actually give you 20Gb of capacity. In flash RAM devices, things can get a bit more complex again, thanks to the small amount of memory which may be used by the device itself for housekeeping. That can vary between device families; a CompactFlash card with a given nominal capacity may actually have a bit less space than a SmartMedia card with the same number on the label. And manufacturers may throw in some more memory to push the real capacity up closer to the stated one, which is what they've done with the USBDrive. It's still about three per cent shy of its claimed capacity, though. -- http://www.dansdata.com/flashcomp.htm (E.g., my 512MB CF card shows up as 487MB in the camera -- a difference of exactly 5%, as would be expected by the MB-vs-MiB scam. I'd be happier if the camera said 487MiB, but we're looking at OSes we do have control over, not others.) And this cheat is getting better (for the seller) with every expansion: 1 MiB is 5% bigger than 1 MB 1 GiB is 7% bigger than 1 GB 1 TiB is 10% bigger than 1 TB So when you go out to buy your 1TB drive this year, you're really only buying 0.9TiB or so. Since all the manufacturers do the same thing, it's possible to consider it fair, at least for comparisons -- but when the customer gets home and formats their drive, I think they'd be happier if the number was the same as on the carton. Just last night I formatted some new 500GB drives, and they eventually came back with 465GB as the displayed capacity. Wouldn't it make more sense to display that as 465GiB? David Talk about a cure worse than the disease! So you're saying that David 256MB flash cards could be advertised as having 268.4MB? A David 512MB RAM stick is mislabelled and could correctly say 536.8MB? David That's just plain craziness. No, it sounds like he wants them advertised as 256MB and 512MiB, respectively -- packaged flash cards tend to use the 1000 multiples, while DRAM uses the 1024. One extra letter doesn't sound all that crazy. How fast is your Ethernet port? 100Mbps or 95.37Mbps? Somewhat archaic now, but how big was your common 3.5 floppy disk (PC HD format)? It actually used a basis of 1,024,000: And if two definitions of the megabyte are not enough, a third megabyte of 1 024 000 bytes is the megabyte used to format the familiar 90 mm (3 1/2 inch), 1.44 MB diskette. -- http://physics.nist.gov/cuu/Units/binary.html What's likely is that the flash and drive manufacturers will either mark their products honestly, or they'll increase the capacity of their product to meet the given label. (Think about the CRT diagonal measurements -- it took a few lawsuits, but they eventually switched from measuring bezel-to-bezel, or total tube diagonal, to viewable. Sure, everyone in technology knew that you had to chop off an inch or two from the advertised value to get the viewable; but that's not enough to meet the standard of truth in advertising.) David Adopting IEC 60027-2 just replaces a set of well-understood David problems with all new problems. Which are clearly solved in the standards document, and remove any ambiguity. Is one extra character really that painful to you? t. - To unsubscribe from this list: send the line unsubscribe linux-kernel in the body of a message to [EMAIL PROTECTED] More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
