IBM TS2250, Setup, Operator, And Service Manual

Page: 69 / 149

Write-Protect Switch
The position of the write-protect switch on the tape cartridge (see
4
in Figure 4-1
on page 4-1) determines whether you can write to the tape. If the switch is set to:
v
The locked position (solid red), data cannot be written to the tape.
v The unlocked position (black void), data can be written to the tape.
If possible, use your server's application software to write-protect your cartridges
(rather than manually setting the write-protect switch). This allows the server's
software to identify a cartridge that no longer contains current data and is eligible
to become a scratch (blank) data cartridge. Do not write-protect scratch (blank)
cartridges; the tape drive will not be able to write new data to them.
If you must manually set the write-protect switch, slide it left or right to the
desired position.
Capacity Scaling
To control the capacity of the cartridge (for example, to obtain a faster seek time)
issue the SCSI command SET CAPACITY. For information about this command,
refer to the
IBM System Storage Ultrium Tape Drive SCSI Reference .
WORM (Write Once, Read Many) Cartridge
Certain records retention and data security applications require a Write Once, Read
Many (WORM) method for storing data on tape. The LTO Ultrium generation 3, 4
and 5 drives enable WORM support when a WORM tape cartridge is loaded into
the drive.
Because standard read/write media are incompatible with the WORM feature, a
specially formatted WORM tape cartridge (see Figure 4-2) is required. Each WORM
cartridge has a unique, worldwide cartridge identifier (WWCID), which comprises
the unique CM chip serial number and the unique tape media serial number. See
“Media Supplies” on page C-5 for information on how to choose and purchase the
appropriate WORM tape cartridges for your library.
Data Security on WORM Media
Certain built-in security measures help ensure that the data written on a WORM
cartridge does not become compromised, for example:
v The format of a WORM Tape Cartridge is unlike that of standard read/write
media. This unique format prevents a drive that lacks WORM-capable firmware
from writing on a WORM tape cartridge.
a67b0024
Figure 4-2. Ultrium Data Cartridge on the left; WORM Cartridge on the right
Chapter 4. Using Ultrium Media
4-3