Abstract: The presence of a disk cartridge in a disk drive is detected by obtaining a measure of the load on the spindle motor of the disk drive and comparing that measure to a threshold value. The measure of load on the spindle motor may comprise (i) the time the spindle motor takes to spin-up to its full operating speed, (ii) the time the spindle motor takes to coast down to its operating speed from a first speed in excess of the operating speed, (iii) the voltage applied across the coils of the spindle motor, or (iv) the current drawn by the spindle motor.

Abstract: A disk cartridge adapted for insertion into a data storage device having an insertion opening, a spindle motor positioned to engage a hub of the disk cartridge, and a cartridge receiving stop having first and second receiving projections. The disk cartridge includes an outer casing having a top surface having a substantially flat middle region and angled peripheral regions; a substantially flat bottom surface defining an opening; a back wall having a rear peripheral edge; a front wall having a front peripheral edge; and side walls that each meet the front wall to form a plurality of non-square shaped front corners. When the disk is inserted into the data storage device, a first engaging projection formed on the front wall engages the first receiving projection of the cartridge receiving stop, a second engaging projection formed on the front wall engages the second receiving projection of the cartridge receiving stop, and the hub engages the spindle motor.

Abstract: A data storage device comprises a cartridge receiving stop having a middle surface and angled outer edges for inhibiting the insertion of incompatible disk cartridges into the data storage device. A disk cartridge adapted for use in the data storage device has opposite front corners. The opposite front corners of the disk cartridge have a non-square shape adapted to avoid interference with the angled outer edges of the cartridge receiving stop. The data storage device may further comprise means for enabling a function of the data storage device upon insertion of a disk cartridge having non-square front corners into the disk drive. The disk cartridge may further comprise a projection positioned on the front peripheral edge of the disk cartridge and adapted to engage an operating member of the enabling means on the middle surface of the cartridge receiving stop.

Abstract: The presence of a disk cartridge in a disk drive is detected by obtaining a measure of the load on the spindle motor of the disk drive and comparing that measure to a threshold value. The measure of load on the spindle motor may comprise (i) the time the spindle motor takes to spin-up to its full operating speed, (ii) the time the spindle motor takes to coast down to its operating speed from a first speed in excess of the operating speed, (iii) the voltage applied across the coils of the spindle motor, or (iv) the current drawn by the spindle motor.