The Std124000N Drive - Seagate STD124000N Product Manual

Chapter 8

The STD124000N Drive

Page 72
The Scorpion 24 uses the helical scan recording method with a four-head cylinder
design. Four direct-drive motors and one brush-type motor are used in the drive.
The read and write functions use LSIs. Engineering decisions—such as the modular
partitioning of the electronics and use of surface mount, low power commercial and
custom LSIs—allow the drives to conform to the industry-accepted 3.5-inch form-
factor. These design features are also important contributors to the overall reliability,
durability and performance of the drive.
The Scorpion 24 mechanism is designed for minimum tape wear and prevention of
damage to the tape. The modes or operational states, such as stop, rewind and
play, reduce mechanism and tape wear. Fewer mechanical mode changes result in
less wear on key drive components. In some cases, the need for a mode change is
circumvented using the Pause mode, which stops the tape without activating the
mechanism. All mode selection is performed by the controller firmware. The host
computer does not directly control mode selection.
A custom timing tracking design (described in detail in Chapter 6), combined with
the four-head cylinder design, implements the specifics of the DDS-3 recording
format standard and provides the precision required to perform seamless appends,
or the ability to add subsequent recorded data frames immediately adjacent to the
last data frames written on the tape.
A bank of jumpers is available at the rear of the drive. These jumpers allow you to
set the SCSI ID for the drive and to change configuration choices. Refer to chapter
3 for information about setting these jumpers.
By using the jumpers, you can also enable terminator power if needed. (The default
for internal models is with terminator power disabled. For external drives, the default
is with terminator power enabled.)
Note. The Scorpion 24 comes supplied with a terminator power fuse to provide
protection from component damage in case the SCSI cable is connected
incorrectly.
Two rectangular front-panel light-emitting diodes (LEDs) indicate a drive busy status
and tape cartridge in place status. When blinking, these LEDs also function as fault
indicators. (Refer to Chapter 4 for a summary of the function of these LEDs.) The
external subsystem also provides a round, green LED on the front panel to indicate
power on.
Theory of Operations
DAT Drives