Optical storage

Optical disks are generally used for storing objects that are accessed infrequently, primarily because of their high capacity and performance characteristics. This section provides an overview of optical storage and its role in OAM. Table 1 lists the optical devices that OAM uses.

Table 1. Optical devices that OAM supports
Device name Disk size Storage slots Internal drives Operator-accessible Media supported Attaches to
3995-131 5.25 inch 144 4 1 sd-REWR Attaches to host system.
3995-132 5.25 inch 144 4 1 sd-WORM Attaches to host system.
3995-133 5.25 inch 144 4 1 sd/dd WORM/REWR Attaches to host system.
3995-111 5.25 inch 144 4 0 sd-REWR Attaches to Model 131.
3995-112 5.25 inch 144 4 0 sd-WORM Attaches to Model 132.
3995-113 5.25 inch 144 4 0 sd/dd WORM/REWR Attaches to Model 133.
3995-C3A 5.25 inch 0 0 1 or 6 sd/dd/qd/8x WORM/REWR Attaches to host system.
3995-C32 5.25 inch 52 2 0 sd/dd/qd/8x WORM/REWR Attaches to Model C3A.
3995-C12 5.25 inch 52 2 0 sd/dd/qd/8x WORM/REWR Attaches to Model C3A/C32 pair.
3995-C34 5.25 inch 104 2 or 4 0 sd/dd/qd/8x WORM/REWR Attaches to Model C3A.
3995-C36 5.25 inch 156 4 or 6 0 sd/dd/qd/8x WORM/REWR Attaches to Model C3A.
3995-C16 5.25 inch 156 4 or 6 0 sd/dd/qd/8x WORM/REWR Attaches to Model C3A/C36 pair.
3995-C38 5.25 inch 258 4 or 6 0 sd/dd/qd/8x WORM/REWR Attaches to Model C3A.
3995-C18 5.25 inch 258 4 or 6 0 sd/dd/qd/8x WORM/REWR Attaches to Model C3A/C38 pair.
3995-SW3* 5.25 inch N/A N/A N/A sd/dd/qd WORM/REWR This drive is used in the C3A, C1x, and C3x libraries.
3995-SW4** 5.25 inch N/A N/A N/A sd/dd/qd/8x WORM/REWR This drive is used in the C3A, C1x, and C3x libraries.
Notes:

REWR = rewritable
WORM = write-once, read-many
sd = single-density (652 MB maximum disk size)
dd = double-density (1304 MB maximum disk size)
qd = quad-density (2600 MB maximum disk size)
8x = eight times density (5.2 GB maximum disk size)

* The 3995-SW3 drive in the C3A, C1x, and C3x libraries is capable of reading only from single-density WORM and rewritable media, not writing to it. It can read from or write to double- and quad-density media.

** The 3995-SW4 drive in the C3A, C1x, and C3x libraries is capable of reading only from single- and double-density WORM or rewritable media, not writing to it. It can read from or write to quad- and 8x-density media. Quad-density and 8x-density drives cannot coexist in the same library.

For information concerning approximate user data disk capacities for the supported media, see Table 1.

The approximate user data disk capacity can vary depending on file sizes. Smaller file sizes take up more space on the disk than larger file sizes due to the increase in extents.

For simplicity, the following 3995 library models are referred to as C1x and C3x respectively: C12, C16, C18, C32, C34, C36, C38.
Related reading: For more information about the 3995 optical library, see the following documents:
Parent topic: Understanding the Object Access Method