Bob_BobR_Retelle@cup.portal.com (11/21/90)
Unformatted capacity of a disk is a measure of the raw information storage ability of the media. Number of tracks times number of sectors per track times bytes per sector equals unformatted capacity. Formatted capacity of a disk is the available data storage regions AFTER such "overhead" areas as sync bytes, track header bytes, sector header and intersector gaps, FAT tables, directories, and boot sectors have been written to the disk. This is why there's usually quite a difference between the "unformatted" and "formatted" capacity figures. The difference can be quite striking on a very high capacity hard drive for instance... BobR
kdq@demott.COM (Kevin D. Quitt) (11/24/90)
In article <36113@cup.portal.com> Bob_BobR_Retelle@cup.portal.com writes: >Unformatted capacity of a disk is a measure of the raw information storage >ability of the media. Number of tracks times number of sectors per track >times bytes per sector equals unformatted capacity. Correct. >Formatted capacity of a disk is the available data storage regions AFTER >such "overhead" areas as sync bytes, track header bytes, sector header and >intersector gaps, Correct > FAT tables, directories, and boot sectors have been written >to the disk. Incorrect. Only the data necessary for allowing physical sector read/writes is considered overhead. The rest of these examples are data. -- _ Kevin D. Quitt demott!kdq kdq@demott.com DeMott Electronics Co. 14707 Keswick St. Van Nuys, CA 91405-1266 VOICE (818) 988-4975 FAX (818) 997-1190 MODEM (818) 997-4496 PEP last 96.37% of all statistics are made up.
bumby@math.rutgers.edu (Richard Bumby) (11/27/90)
In article <1014@demott.COM> kdq@demott.COM (Kevin D. Quitt) writes: > In article <36113@cup.portal.com> Bob_BobR_Retelle@cup.portal.com writes: . . . <undisputed matted deleted> . . . > > > FAT tables, directories, and boot sectors have > >been written to the disk. > > Incorrect. Only the data necessary for allowing physical sector > read/writes is considered overhead. The rest of these examples are data. > I agree that the original interpretation is incorrect, but the confusion may come from the fact that the chkdsk program in DOS (at least in version 2.11) excludes all of the goodies up to the ROOT directory from its count. Here is a sample of chkdsk output on my 640K "hard-RAM" 632832 bytes total disk space = 618K 3072 bytes in 3 directories (excluding root) 612352 bytes in 43 user files 1024 bytes in bad sectors (an interesting story) 16384 bytes available on disk The "bad sector" is my own creation. It seems that the pointer to cluster #100H kept getting corrupted into 000, so I declared that cluster bad to keep it from being allocated. -- --R. T. Bumby ** Math ** Rutgers ** New Brunswick ** NJ08903 ** USA -- above postal address abbreviated by internet to bumby@math.rutgers.edu voice communication unreliable -- telephone ignored -- please use Email