User's Manual

Theory of operations 41
original data string, using fewer characters to represent the strings. Because these
smaller symbols are substituted for the longer strings of data, more data can be
stored in the same physical space.
Some important benefits result from data compression in DAT drives:
• The same amount of information can be stored on a smaller length of tape.
• More data can be stored on a given length of tape.
• Performance can more closely parallel to that of high-transfer-rate computers.
More information can be transferred in the same time interval.
For more information on data compression in Scorpion drives, see the Scorpion 40
Product Manual, part number 10006598-001, Rev. B.
About the DDS data cartridge
The Scorpion 240 tape drive is designed to use data-grade DDS cartridges, which
comply with the specifications in the
3.81-mm Helical-Scan Digital Computer Tape
Cartridge for Information Interchange, ANSI X3B5/89-156
standard. Seagate
recommends Seagate-qualified, data-grade DDS DAT cartridges (Model M32000: 90
meters; and Model 34000: 120 meters, Model 324000: 125 meters) to ensure optimal
data integrity and reliability.
Seagate also recommends the use of a Seagate-qualified DDS head-cleaning
cartridge (Model STDMCL). You can order both DDS data and head-cleaning
cartridges from Seagate.
Note. Proper maintenance of the drive requires that you use the DDS head-
cleaning cartridge after every 50 hours of read/write operation and whenever
the rectangular, green cartridge-in-place LED flashes during operation.
These small (approximately 2 inches × 3 inches × 0.4 inch) cartridges house
magnetic tape that is 3.81 mm (0.150 inch) wide. The DDS cartridges are slightly
bigger than a credit card. Figure 20 shows key features of the DDS cartridge.
Slider Lock (2)
Slider Lock (1)
Datum Holes
File Protect Hole
(Restorable)
Recognition
Holes (1, 2, 3, 4)
(4)
(1)
(2)
(3)
Lid Lock
(Locked by Slider)
Figure 20. DDS cartridge design features