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38
Motors and control circuits
Timing tracking circuitry
Signal-processing electronics
Write head B
Figure 21. Alternating azimuth angles on tape tracks
The Scorpion 40 drive uses four direct-drive, brushless motors—the capstan,
cylinder and two reel motors. Using these small, direct-drive motors provides
maximum reliability. The cylinder motor rotates the cylinder. The capstan motor
moves the tape. The mode motor loads and ejects the cartridge. The two reel motors
turn the tape reels.
The cylinder, capstan and reel servos are controlled by custom ASICs and the motor
control firmware.
The fifth motor in the mechanism is a brush-type mode motor. This motor controls
(selects) the mechanism mode. Because the mode motor is not frequently used, and
due to space and torque requirements, a brush-type motor is best suited to this
application. The mode motor performs the mode changes as directed; for example,
this motor conditions the mechanism to eject the cartridge.
The timing tracking circuitry of the drive is designed to provide high precision tracking
and head positioning. The timing tracking system, in conjunction with the four-head
read-after-write (RAW) design provides for reliable high-density data recording with
maximum storage efficiency.
The signal-processing electronics circuitry in the drive is made up of several
components. The drive's main control microprocessor, data engine, and data buffer
management circuitry are all integrated in a single IC package. A single chip DDS
formatter LSI communicates with the microprocessor and with the read and write
LSIs. The C3 ECC coprocessing capability and a second buffer memory control
function are also included in this IC. Other vital components are the high-
performance SCSI LSI chip, the flash memory, and the DRAM buffer memory, is 8
Mbytes.
Scorpion 40 DDS-4 Product Manual, Version A
Write head A
20˚ head azimuth
3 tape tracks
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