DEC VAX 4000 300 Manual page 32

input devices when you install software or copy data to your system. You
use tape cartridges and tapes as output devices when you copy software or
data from your system. You can copy individual files or programs, or you
can copy (back up) the contents of an entire fixed disk. Tapes are commonly
used to archive data.
Mass Storage Controllers and Adapters
All mass storage devices require a controller, a device that controls activity
between the CPU and the mass storage devices. While the controller for a
DSSI device is built into the storage device, other storage options require a
controller module located in your system's card cage. The controller for the
TK70 tape drive is the TQK70; the KDA50 is a controller for RA-series disk
drives. Each KDA50 controller supports up to four RA-series disk drives.
The KZQSA adapter allows the CPU to communicate with the TLZ04 tape
drive or RRD40-series digital compact disk drive. Each KZQSA adapter
can support up to two drives.
The CPU communicates with DSSI devices through a Digital Storage
Systems Interconnect (DSSI) adapter, which is built into the CPU. Your
VAX 4000 system has two DSSI adapters and, hence, two separate DSSI
busses. Each DSSI bus is capable of supporting seven DSSI devices. A
third and fourth DSSI bus can be added to your system by using up to two
KFQSA DSSI storage adapter modules. Each KFQSA storage adapter can
support up to seven DSSI devices.
NOTE: As of this printing, the KFQSA storage adapter does not yet support
the TF85 tape drive.
1.2.2.2 Mass Storage Subsystems
Several optional mass storage subsystems are available for VAX 4000
systems. Such subsystems include RRD42 compact disc subsystem, the
RV20 Optical Disk Subsystem, TSZ07, TS05, and TU81 tape drives, and the
SA600 Storage Array (with up to eight RA90 disk drives). If your system
includes an optional mass storage subsystem, refer to the user's guide or
owner's manual for that subsystem for instructions on how to operate the
device.
1.2.2.3 Mass Storage Expanders
You can expand the mass storage and Q-bus capacity of your VAX 4000
system by using the following expanders:
• The R400X mass storage expander provides space for up to seven
additional RF-series ISEs or up to six RF-series ISEs and a tape drive
(TF85 or TLZ04). Using R400X expanders, you can fill both DSSI busses
for a total of 14 DSSI devices.
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