Abstract: A disk drive is disclosed comprising a microprocessor, a non-volatile serial semiconductor memory for storing code segments of a control program, a first semiconductor memory for storing code segments of a loader program, and a second semiconductor memory for receiving the code segments of the control program. When the disk drive is powered on, the microprocessor executes the loader program from the first semiconductor memory to load the control program from the non-volatile serial semiconductor memory into the second semiconductor memory. The microprocessor then executes the control program from the second semiconductor memory.

Abstract: A disk drive is disclosed comprising a semiconductor memory comprising a cache buffer having a plurality of segment pools, each segment pool comprising a plurality of cache segments, and each cache segment comprises 2k number of blocks where k is a predetermined integer for each segment pool. Host commands have a command size comprising a plurality of bits indicating a number of blocks of data associated with the host command. Each bit of the command size is mapped to a corresponding segment pool in order to allocate cache segments for the host commands.

Abstract: A dual channel helical scan recording system (30) includes a rotating dum (36) having sets of heads (W1, W2) (R1, R2) mounted on its peripheral surface (56). A set of write heads (W1, W2) is situated on an opposite side of the drum (36) from a set of read heads (R1, R2). The write heads (W1, W2) simultaneously write two adjaent tracks (T1, T2), which are read for verification 180 detrees later by corresponding read heads (R1, R2). The heads (W1, W2, R1, R2) are strategically mounted on the drum (36) with respect to angular and axial placement, and have selected head widths and azimuthal angles. Should a block of data (317) written to tape (32) be determined, during readback, to be bad block, that bad block is subsequently rewritten on the tape (32) in the course of writing good blocks and amongst other good blocks. The rewritten block is recorded at a row position on the tape which is sufficiently displaced from the row position of a previous writing to avoid media defects occuring on the tape.