AT&T 3B2/300 Technical Reference Manual page 34

EQUIPMENT D E S C R I P T I O N - - - - - - - - - - - - - - - - - - - - - - - - - - -
storage. Refer to the
AT&T SCSI (Small Computer System Interface) Definition,
(Select Code 305-013), for
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additional information on this capability. ._)
Removable Media Expansion
There are various forms of removable media available with 3B2 computers. Some are standard
equipment while others are optional.
Floppy Disk.
A second 720-kilobyte, double-sided, 96 tracks-per-inch, floppy disk drive can be
equipped in an AT&T/XM. Connection to the host 3B2 computer is via a CM195H Cartridge Tape
Controller (CTC) Card. While it is possible to equip more than two floppy disk drives on a system,
equipage of more than two floppy disk drives is not practical. Two floppy disk drives provide
drive-to-drive operational capabilities that are considered to be the optimum floppy disk drive equipage.
23-Megabyte Cartridge Tape. One or more 23-megabyte cartridge tape drives can be added to a
3B2 computer. The drive can be mounted in an AT&T/XM cabinet or by itself in a Tape Module
cabinet. Each cartridge tape drive connects to the host 3B2 computer via a CMl 95H Cartridge Tape
Controller Card that is installed in a 3B2 computer feature card slot. For a 3B2/400, the first cartridge
tape controller is equipped in slot 2. Each CM195H CTC Card can interface two peripheral devices
(one floppy disk and one cartridge tape drive). Simultaneous access of the two devices connected to the
same CMl 95H CTC Card is not possible.
60- and 120-Megabyte Cartridge Tape.
Additional 60- and 120-megabyte cartridge tape drives
can be added to an existing 3B2 computer using a SCSI. A CMl 95W SCSI Host Adapter Card provides
the interface between the computer and the SCSI bus. Refer to the
AT&T SCSI (Small Computer System
Interface) Definition, (Select Code 305-013), for additional information on this capability.
Rewritable Optical Disk. The SCSI Rewritable Optical Disk Module can be added to an existing
3B2 computer. The optical disk removable media provides approximately 584 megabytes (292
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megabytes per side) of formatted storage capacity. A CM195W SCSI Host Adapter Card provides the ·...,;
interface between the computer and the SCSI bus. Refer to the
AT&T SCSI (Small Computer System
Interface) Definition, (Select Code 305-013), for additional information on this capability.
AT&T 3BNET Local Area Network
The AT&T 3B2 computers can serve as nodes on the AT&T 3BNET Local Area Network (3BNET
LAN). The 3BNET LAN is an Ethernet compatible network operating at 10 megabits per second using
the Carrier Sense Multiple Access with Collision Detection (CSMA/CD) algorithm. The lowest level
protocols conform to the Institute of Electrical and Electronics Engineers (IEEE) 802.3 standards for
Carrier Sense Multiple Access with Collision Detection (CSMA/CD) local area networking. The
connection of a 3B2 computer to the 3BNET is via a CM195A Network Interface Card that is installed
in a 3B2 computer feature card slot.
AT&T STARLAN Network
The AT&T STARLAN network is a low-cost, local area network for linking MS-DOS* and UNIX
system-based computers. The STARLAN network runs at 1 megabit per second on twisted pair wiring.
The wiring is based on AT&T's Premises Distribution System (PDS). The high-level protocols support
applications written for Microsoft Networks.
Connection to STARLAN from a 3B2 computer is provided by a CM195U Network Access Unit
(NAU) Card that plugs into a 3B2 computer feature card slot.
• Registered trademark of Microsoft Corp.
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