| Professional Computer|
| 1985 (1985)|
| Convergent Technologies|
5¼-inch floppy disks, optional quarter-inch cartridge tapes
Motorola MC68010 with custom Memory management unit clocked at 10Mhz
The 3B1 (also known as the PC7300, or Unix PC) was a Unix workstation computer originally developed by Convergent Technologies (later acquired by Unisys), and marketed by AT&T in the mid- to late-1980s. Despite the name, the 3B1 had little in common with AT&T's other 3B-series computers.
10 MHz Motorola MC68010 (16 bit external bus, 32 bit internal) with custom, discrete MMU
Internal MFM hard drive, originally 5 MB, later models with up to 67 MB
At least 512K RAM on main board, expandable via expansion cards
3 expansion slots
Monochrome green phosphor 10-inch (250 mm) monitor
Internal 300/1200 bit/s modem
AT&T Unix PC Wikipedia
The initial PC7300 model offered a very limited 512 KB of memory and an extremely slow 5 MB hard drive. This model, although progressive in offering a Unix system for desktop office operation, was painfully slow and had an aggravating 'grinding' noise even when not in active use. The modern-looking "wedge" design was innovative, and in fact the machine gained notoriety appearing in many movies as the token "computer."
A later enhanced model was renamed "3B1". The cover was redesigned to accommodate a full-height 67 MB hard drive. This cover change added a 'hump' to the case, expanded onboard memory to 1 or 2 MB, as well as added a better power supply.
The operating system is based on Unix System V Release 2, with extensions from 4.1 and 4.2 BSD, System V Release 3 and Convergent Technologies. The last release was 3.51.SMC BASIC
LPI Pascal (programming language)
LPI C (programming language)
SMART System (Office Suite)
AT&T Word Processor
SMART Word Processor
HoneyDanBer UUCP package.
Various Shells: Bourne, C, and Korn
SPICE/NUTMEG (circuit simulation tool)
The Store is a public domain software repository which was available for all 3B1 users.DOS-73 8086 co-processor card running MS-DOS, which could be fitted with an 8087 math co-processor chip. This board was designed and built for AT&T by Alloy Computer Products of Framingham MA.
RAM card could be added using 1 or 2 MB RAM cards (up to a maximum of 4 MB)
EIA/RAM combo cards contained extra RAM and two RS-232 serial ports.
Dual EIA port card
StarLAN 1Mbit/s LAN card
Ethernet 10 Mbit/s LAN card
VoicePower card allowed for the capture and digital recording of voice conversations.
Tape drive card provided interface for 23 MB MFM Tape Cartridge Drive.
Expansion chassis card was hard-wired to Expansion Chassis (with five added slots)
StarLAN – 1 MB/s local area network typically used in star format.