The best chance of success in using the Stand-alone Disk Image Dump and Restore program is to use a replacement disk drive that is identical to the original.
If you cannot find an identical replacement, then you can try a disk drive that is compatible with the original. This replacement drive must be able to support the geometry of the original. In general, this means that this replacement drive must be the same size or larger. (See "A Note on Disk Geometry: Cylinder/Head/Sector Terminology" for an explanation.)
When you restore a disk image to a replacement IDE drive, the computer's CMOS Setup must be set for the geometry of the original drive. On computers that allow it, the easiest way to do this is to not run the CMOS hard-drive detection routines after replacing the drive. For example, on many motherboards that contain an Award BIOS, it is possible to bypass automatic setup and even manually specify drive geometry. Consult the documentation supplied by the manufacturer of the motherboard or the computer.
If you have a motherboard in which setup routines run automatically without the capability to override the setups, you may have problems. If the geometry of the replacement drive is different from your original drive, either you will not be able to use the disk image from the original disk, or at best, the disk will not be bootable. You must then find an identical replacement drive.
| Note: | If you successfully use a replacement IDE drive that is larger than the original, you will not be able to utilize all of the space on the replacement drive. The replacement drive will appear to the system to be the size of the original. |
Restoring a disk image from one SCSI drive to another is often more reliable than from one IDE drive to another. SCSI drives use standard geometries within a range of storage sizes. For example, modern SCSI disk drives that are less than 1GB have the same number of heads and sectors. Only the number of cylinders changes to account for the different storage sizes within this range. If you have a 700MB SCSI disk drive to replace a 300MB SCSI disk drive, you should be able to restore the disk image from the 300MB drive to the 700MB drive.
For SCSI disk drives, you may need to perform a low-level format of the replacement disk drive by using the low-level format utility supplied by the manufacturer of the drive adapter. For example, if the replacement drive uses an Adaptec controller, use the scsifmt.exe utility supplied by Adaptec.
The geometry of a disk drive is the combination of the numbers of cylinders, heads, and sectors that the drive has, along with the size of each sector.
Hard disk drives are made of multiple magnetic platters (flat discs) attached to a central spindle. A read/write head attached to an arm is placed above and below each platter surface. The arm can move across the platter. A track is the circle on the platter that is traced by the arm when the arm is at a given position and the platter spins. A cylinder is the set of tracks on all the platters that are at the same position. A sector is a fixed block of data within a track. For most disk drives, each sector has 512 bytes.
The storage size of a disk is determined by the standard formula:
512 bytes X (number of cylinders) X (number of heads) X (number of sectors per track)
Attention: The Stand-alone Disk Image Dump and Restore program only supports disk drives with 512-byte sectors. The use of this program with a disk drive that has a sector size other than 512 bytes will result in lost data.