Re: [smartmontools-support] Disk Geometry - Slightly OT

 Re: [smartmontools-support] Disk Geometry - Slightly OT From: Tim Small - 2009-11-17 11:37:27 ```Al Grant wrote: > Current partition structure: > Partition Start End Size in > sectors > > 1 P FAT16 >32M 0 1 1 6 254 63 112392 > [DellUtility] > 2 P HPFS - NTFS 7 2 60 1312 109 13 20971520 > [RECOVERY] > 3 * HPFS - NTFS 1312 109 14 38913 37 36 604055552 > [Family] > > (a) I assume the Start/End values are CHS values? > Looks like it. > (b) If so, isnt C*H*S = block size (ie should be same as size in sectors? > Close - you need to know what the pretend geometry is (lets guess at something like 38913/255/63 - since most things use 255/63 these days), and also that cylinders and heads are numbered from zero, but sectors are numbered from 1 (just to make things a bit more difficult), so: The first sector on the disk is 0 0 1, and start of partition 1 is 63 sectors-in (0 0 1 to 0 0 63 contains the mbr). The end of partition 1 is at track 6, head 254, sector 63. i.e. at the end of the 63rd sector of the 7th track on the 255th head. So the size of partition 1 = (7 * 255 * 63) - (1 * 63) = 112392 http://en.wikipedia.org/wiki/Cylinder-head-sector#Examples Ta, Tim. ```

 [smartmontools-support] Disk Geometry - Slightly OT From: Al Grant - 2009-11-17 08:40:49 ```Hi All Apologies for this being slightly OT, but smartctl and drive geometry seem to go hand in hand. The following is taken from testdisk on a ddrescue.bin file and shows the partition structure. Current partition structure:     Partition                  Start                    End Size in sectors  1 P FAT16 >32M               0   1  1         6 254 63       112392 [DellUtility]  2 P HPFS - NTFS              7   2 60       1312 109 13     20971520 [RECOVERY]  3 *  HPFS - NTFS           1312 109 14     38913  37 36    604055552 [Family] (a) I assume the Start/End values are CHS values? (b) If so, isnt C*H*S = block size (ie should be same as size in sectors? Still struggling to come to terms with drive geometry numbers!!!! All help appreciated. Regards -Al ```
 Re: [smartmontools-support] Disk Geometry - Slightly OT From: Tim Small - 2009-11-17 11:37:27 ```Al Grant wrote: > Current partition structure: > Partition Start End Size in > sectors > > 1 P FAT16 >32M 0 1 1 6 254 63 112392 > [DellUtility] > 2 P HPFS - NTFS 7 2 60 1312 109 13 20971520 > [RECOVERY] > 3 * HPFS - NTFS 1312 109 14 38913 37 36 604055552 > [Family] > > (a) I assume the Start/End values are CHS values? > Looks like it. > (b) If so, isnt C*H*S = block size (ie should be same as size in sectors? > Close - you need to know what the pretend geometry is (lets guess at something like 38913/255/63 - since most things use 255/63 these days), and also that cylinders and heads are numbered from zero, but sectors are numbered from 1 (just to make things a bit more difficult), so: The first sector on the disk is 0 0 1, and start of partition 1 is 63 sectors-in (0 0 1 to 0 0 63 contains the mbr). The end of partition 1 is at track 6, head 254, sector 63. i.e. at the end of the 63rd sector of the 7th track on the 255th head. So the size of partition 1 = (7 * 255 * 63) - (1 * 63) = 112392 http://en.wikipedia.org/wiki/Cylinder-head-sector#Examples Ta, Tim. ```