Use of tapes22
HP restricted
The following table gives the minimum acceptable Capacity Proportion Values and the approximate
capacity they will give:
NOTE: Capacities are approximate and can be affected by defects that reduce the actual capacity
of the tape. Other factors, such as compression and block packing, may also affect capacity.
WORM media
HP Ultrium-3 WORM (Write Once—Read Many) data cartridges are two-tone grey/yellow to
distinguish them from RW media. They have a unique Cartridge Type stored in the Cartridge
Memory, so that they will be rejected by non-WORM compatible drives. For automation
configurations with auto-eject disabled, the cartridge will not be physically ejected from the drive
but held at the “ready eject” position.
The write-protection tab behaves as on Read/Write (RW) cartridges.
How WORM media works
Drives use the EOPD (End of Protected Data) value to control the use of WORM tapes.
EOPD is a logical position on tape that is automatically calculated based on the End of Data (EOD)
value read from the Cartridge Memory (CM) when the cartridge is loaded into the drive. The EOD
value is an “intrinsic” code stored and protected in the Cartridge Memory of each WORM
cartridge, and updated after each write session. The EOPD indicates that data between BOM and
this position cannot be overwritten.
The EOPD value is held within the drive’s memory. It is updated automatically and continuously as
each block of data (typically 64 or 128 KB) is written to tape, so the EOPD value indicates a logical
position immediately after the last block of data written to tape.
When the cartridge is unloaded, the drive updates the EOD value in CM to reflect the end of
successfully written data on the cartridge, and clears the EOPD value stored within the drive. Any
future writes to the cartridge will occur after the location of the EOD, which will become the initial
location for EOPD during the next write operation.
Changes to SCSI commands
New additional sense codes and TapeAlert flags
ASC/Qs:
• 300Ch (WORM medium—overwrite attempted)
• 300Dh (WORM Medium—integrity check failed)
Cartridge Min. capacity proportion value Resultant approx. min. capacity Max. capacity
Ultrium 2
1605h 17.2 GB 200 GB
Ultrium 3
151Ah 33 GB 400 GB
Ultrium 4
1055h 51 GB 800 GB
