User's Manual

Theory of operations
41
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 22. DDS Drive Cartridge Design Features
Qualified DDS cartridges are designed with specific write-protect, lid and other
features for information interchange and are tested to comply with the ANSI DDS
specifications.
The DAT 72 and DDS-4 drives also recognize all MRS cartridges when MRS is
enabled. MRS cartridges have a series of alternate opaque and clear stripes at the
beginning of the tape. These stripes classify the media as data-grade, rather than
audio-grade media. Figure 23 shows the four recognition holes that allow the drive
sensors to identify the type of tape, its magnetic thickness, and whether the tape is
prerecorded, unrecorded or is a cleaning cartridge. Other cartridge features allow the
drive to determine the cartridge in, BOT and EOT points.
The cartridge also provides for write protection so that existing data on the cartridge
is not overwritten (See Figure 25). A write-protected cartridge allows the existing
data to be read but does not allow new data to be written to the tape.
Note:
A write-protected cartridge
prevents the system log (in
the system area) from being
updated.
Figure 23. Write-Protect Tab on the
DDS Cartridge
Write
Enabled
Write
Protected