A discrepency between used space and free space can be explained by the issue of 'slack space'.
That is, on a hard drive you don't just store files as bytes on their own. Rather, the drive is broken down into 'building blocks' of allocation units called clusters. Each file must consume a minimum of one cluster. So, say your drive uses 32 KB clusters and you save a 400 byte file. 32 KB is still used for that file regardless. If you save a 34 KB file then two clusters will be used, etc. Therefore having folder wtih a large number of small files leads to a lot of 'slack space', which is, the unused space that fills up the rest of the cluster. --- In [email protected], Jim Purcell <[EMAIL PROTECTED]> wrote: > > > My question is.......How come that a hard drive or partition > > will bloat over time and if you try to add up the individual > > contents it never comes up to the total being reported for > > the drive? > > It's about overhead. A drive or partition has a certain amount of > space used by data, but it also needs space for the 'overhead' that > is information about the file, etc. I have always thought that > stating total drive space instead of usable space is a bit like when > a cars engine horsepower is stated as the power created with nothing > attached to the engine. But things like the alternator, fuel pump and > water pump use horsepower that is NOT available for moving the car. > Maybe that is why they switched to the Liter rating or something > similar. > > There is also the old issue of million bytes vs Megabytes. Sometimes > the mfg will state the drive size in terms of millions of bytes or > trillions now. Look at it in the k-bytes values [since those are the > numbers I have memorized.] > ! kilobyte is 1024 bytes, not a thousand bytes. This results because > computers use binary numbers. Decimal numbers given are expressions > of some value of 2^nth power. Each time you ad a bit you increase the > nth power. Decimal numbers used to express binary equivalents do not > come out in even powers of ten. So they use terms like 'k' or 'M' > when have different values in the non computer world. > > I think the problem in question is more related to the overhead than > in the Meg vs Million, but the latter is confusing, especially with > larger drives. > > Jim > ------------------------ Yahoo! Groups Sponsor --------------------~--> AIDS in India: A "lurking bomb." Click and help stop AIDS now. http://us.click.yahoo.com/VpTY2A/lzNLAA/yQLSAA/67folB/TM --------------------------------------------------------------------~-> If you have any questions or problems with any aspect of this site, please feel free to contact me directly [EMAIL PROTECTED] Please do not post personal issues directly to the group. To unsubscribe from this list, send an email to [EMAIL PROTECTED] Thank you for using A-1 Computer Tech Yahoo! Groups Links <*> To visit your group on the web, go to: http://groups.yahoo.com/group/A-1-Computer_Tech/ <*> To unsubscribe from this group, send an email to: [EMAIL PROTECTED] <*> Your use of Yahoo! Groups is subject to: http://docs.yahoo.com/info/terms/
