Sun Microsystems StorEdge L400, Installation And User Manual, Page: 136 / 162

C-2 Sun StorEdge L400 Installation and User’s Guide • April 1998
C.2 Tape Formats and Capacities
The tape drive in the tape library can read and write data in an AME format only.
AME media is the only recommended tape format for use with the Sun StorEdge
L400 tape library. The 8900 tape drive treats the following formats as read-only:
■
8200
■
8500
■
8500c (compressed)
Note –
After reading any tape format other than AME, the 8900 tape drive must be
cleaned prior to any further use.
C.3 Choosing a Cleaning Cartridge
Use only Sun approved cleaning cartridges in the tape library. Cleaners designed for
video use are very abrasive and can damage the tape head and mechanism. Cleaners
that require a cleaning fluid are not recommended.
C.4 Data Capacity With Data Compression
The data capacity of drives with data compression is dependent on the redundancy
of the stored data. Sun specifies capacity figures that assume a compression ratio of
two to one (2:1). The compressibility of data can vary. Text and binary files tend to
compress at about a three to one (3:1) ratio. Image files are typically not redundant
and do not compress well.
C.4.1 Hardware Data Compression
Data compression can be done by the drive’s internal hardware-based data
compression. This is specified by the format/device identifier as shown in
TABLE C-1
.
One disadvantage of this approach is that this data format is not readable by the
earlier drives other than the 8900 because they do not incorporate hardware data
compression.