![]() AT&T UNIX PC  | |
| Manufacturer | Convergent Technologies[2] | 
|---|---|
| Type | Professional Computer | 
| Release date | March 26, 1985[3] | 
| Introductory price | US$5,095 (equivalent to $13,900 in 2022) - US$7,290 (equivalent to $19,800 in 2022)[3][4] | 
| Media | 5¼-inch floppy disks, optional QIC tapes | 
| Operating system | AT&T UNIX v3.51[1] (Based on SVR2) | 
| CPU | Motorola 68010 with custom MMU clocked at 10 MHz | 
| Memory | 512 KB to 4 MB RAM | 
| Storage | 10 MB, Optional 20 MB, 40 MB,[2] and 67 MB hard drives[1] | 
| Display | 12 inches (30 cm), 720 x 348 | 
| Input | Keyboard, 3-button Mouse | 
| Connectivity | RS-232 port, Parallel port, 3 phone jacks | 
| Mass | 40 lb (18 kg) | 
The AT&T UNIX PC is a Unix desktop computer originally developed by Convergent Technologies[2] (later acquired by Unisys),[5][1] and marketed by AT&T Information Systems in the mid- to late-1980s. The system was codenamed "Safari 4"[6] and is also known as the PC 7300, and often dubbed the "3B1". Despite the latter name, the system had little in common with AT&T's line of 3B series computers. The system was tailored for use as a productivity tool in office environments and as an electronic communication center.[7]
Hardware configuration


- 10 MHz Motorola 68010 (16-bit external bus, 32-bit internal) with custom, discrete MMU[2]
 - Internal MFM hard drive, originally 10 MB,[3] later models with up to 67 MB[1]
 - Internal 5-1/4" floppy drive[2]
 - At least 512 KB RAM on main board (1 MB or 2 MB were also options), expandable up to an additional 2 MB via expansion cards (4 MB max total)[2]
 - 32 KB VRAM
 - 16 KB ROM (up to 32 KB ROM supported using 2x 27128 EPROMs)
 - 2 KB SRAM (for MMU page table)
 - Monochrome green phosphor 12-inch (300 mm) monitor[2]
 - Internal 300/1200 bit/s modem[2]
 - RS-232 serial port[2]
 - Centronics parallel port[2]
 - 3 S4BUS expansion slots[2]
 - 3 phone jacks[2]
 
PC 7300
The initial PC 7300 model offered a modest 512 KB[2] of memory and a small, low performance 10 MB hard drive.[3] This model, although progressive in offering a Unix system for desktop office operation, was underpowered and produced considerable fan and drive bearing noise even when idling. The modern-looking "wedge" design by Mike Nuttall was innovative, and the machine gained notoriety appearing in numerous movies and TV shows as the token "computer".[8]
AT&T 3B/1
An enhanced model, "3B/1", was introduced in October 1985 starting at US$8,495 (equivalent to $23,100 in 2022).[9][1] The cover was redesigned to accommodate a full-height 67 MB hard drive.[1] 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.[1]
S/50
Convergent Technologies offered an S/50 which was a re-badged PC 7300.[10]
Olivetti AT&T 3B1
British Olivetti released the "Olivetti AT&T 3B1 Computer" in Europe.[11]
Operating system

The operating system is based on Unix System V Release 2,[2] with extensions from 4.1 and 4.2 BSD, System V Release 3 and Convergent Technologies.[1] The last release was 3.51.[1]
Windowing software (xt/layers) from SVR3 was provided to allow connection to a DMD 5620 graphics terminal.
Programming languages
Application software
- Business Graphics (produces chart graphics from 20/20 spreadsheet data)
 - dBASE III (DBM)[3]
 - Informix (DBM)
 - Oracle (DBM)
 - Paint Power (drawing package)
 - Samna/AT&T Write Power 2 (word processor/spreadsheet)
 - Samna Plus (word processor/spreadsheet)[12]
 - SMART System (Office Suite)
 - Sound Presentations (presentation graphics)[13]
 
Spreadsheet software
Word processors
Games
Utility
Expansion cards
The UNIX PC has three proprietary S4BUS slots for expansion cards:
- DOS-73 8086 co-processor card running at 8 MHz, Hercules graphics-compatible, with 512 KB RAM, an RS-232 COM2 port and optional 8087 math co-processor. Mouse, floppy, modem (on COM1), and printer are shared in a DOS session. MS-DOS 3.1 was included. This board was designed and built for AT&T by Alloy Computer Products of Framingham, MA.
 - RAM could be added using 512 KB RAM or 2 MB RAM cards, up to a maximum of 4 MB (2 MB on the motherboard and 2 MB on expansion cards).
 - EIA/RAM combo cards contained extra RAM (512 KB, 1 MB, or 1.5 MB) and two RS-232 serial ports.
 - Dual EIA port card (same card as the EIA/RAM but without the RAM sockets)
 - StarLAN 1 Mbit/s (1BASE5) network over twisted-pair wire local area network typically used in star format
 - Ethernet 10 Mbit/s LAN card (AMD Lance-based) using AUI connector and Wollongong TCP/IP stack/drivers
 - AUDIX Voice Power (“Speech Processor”) card allowed for the capture and digital recording of voice conversations. This was an option of the "Integrated Solution" package for the AT&T System 25 PBX where the UNIX PC served as the "Master Controller".[17]
 - PC/PBX Connection Package 4 for AT&T PBX System 75 or System 85
 - Floppy Tape card provided interface for 23 MB MFM Tape Cartridge Drive (e.g. Cipher FloppyTape 525)
 - QIC-02 card for tape backup
 - Expansion chassis card was hard-wired to the externally-powered Expansion Unit with five additional S4BUS slots (manufactured by Alloy Computer Products)
 - Piiceon Model SR-2048 (2 MB) RAM expansion card
 
Public domain software
The STORE! was a public domain software repository provided by AT&T and accessible via dialup UUCP.[1][18]
Emulation
Cancelled successor
Three prototypes of a follow-on "P6" model were alleged to have been built[19][1] with the specifications claimed to be:
- Motorola 68020
 - Optional Motorola 68881 FPU
 - SIMM sockets for up to 16 MB RAM
 - Color monitor
 - 2400 baud modem
 - 60 MB QIC tape
 
See also
References
- 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 "3b1 FAQ". unixpc.org. Retrieved 1 August 2019.
 - 1 2 3 4 5 6 7 8 9 10 11 12 13 14 Mayer, Alastair J. W. "System Review: The AT&T UNIX PC" (PDF). Byte. No. May 1986. pp. 254–262. Retrieved 2019-08-01.
 - 1 2 3 4 5 6 7 8 9 10 11 12 13 14 Howitt, Doran (1984-04-08). "At Last, AT&T's 7300/Unix PC". Infoworld. p. 17. Retrieved 2019-08-01.
 - ↑ "AT&T Introduces Computer Gear Aimed at IBM-Led Office Market".
 - ↑ CBR Staff Writer (December 13, 1988). "UNISYS Corp Puts Ely in Charge of $2,000m UNIX Group". Tech Monitor. New Statesman Media Group Ltd. Retrieved November 29, 2021.
 - ↑ "NEW AT&T COMPUTER OFFICE GEAR". Chicago Tribune. March 27, 1985.
 - ↑ AT&T, Select Code 999-601-311IS, AT&T UNIX PC Owner's Manual (1986)
 - ↑ "AT&T PC 7300". Starring the Computer.
 - ↑ Petrosky, Mary (October 14, 1985). "6300 Plus Launched By AT&T". InfoWorld. Vol. 7, no. 41. p. 8.
 - ↑ "Vendors of Multiuser Microcomputer Products". Infoworld. 1986-10-13.
 - ↑ "Olivetti Technical Specifications". Olivetti.
 - ↑ "Samna Plans Unix-based Product Line". InfoWorld. June 16, 1986. p. 17.
 - 1 2 3 4 5 Satchell, Stephen (1985-09-23). "A Look at Software for AT&T's Unix PC". Infoworld. pp. 32–33. Retrieved 2019-07-30.
 - ↑ "Games".
 - ↑ "Comp.sources.3b1 Archive Volume 1".
 - ↑ "Miscellaneous Software".
 - ↑ AT&T System 25 Reference Manual. September 1989.
 - ↑ "The STORE".
 - ↑ "SVR3.5 + source code".
 
External links
- AT&T Leapfrogs IBM With the Unix PC., InfoWorld, April 15, 1985, pp. 15–17
 - The AT&T Unix PC, article from BYTE magazine Volume 10 Number 05: Multiprocessing (May 1985), pp. 98–106
 - The AT&T Unix PC Review, article from BYTE magazine Volume 11 Number 05: Multiprocessing (May 1986), pp. 254–262
 - comp.sys.3b1 FAQ
 - AT&T 3B1/7300 (UNIX PC) Information
 - AT&T UNIX PC at old-computers.com
 - http://bitsavers.trailing-edge.com/pdf/att/3b1/
 - http://www.unixpc.org
 
