Reading and Writing to a Disk Data must be written to the disk through a process called flux transition before it can be read. Flux transition is a process of electromagnet changing the charge to either positive or negative charge. RLL began data compression techniques, it is used on most IDE, SCSI, etc drives. This is not used much on the newer hard drives. A hard disk can be divided into 4 subdivisions.
Partitioning disks can improve disk efficiency.
The bigger the disk the larger the cluster size. The first sector 0 is reserved for the master boot record. The master bot record contains the mapping for all partitions on all drives. The compression utility works between the operating system and disk controller to intercept files to be compressed before they are written to the disk. DOS and Win3x use a program called DBLSpace while Win95 uses DriveSpace which can compress data on floppies and removable drives.