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UNIX PC / PC 7300 / 3B1[1]
Atandt unix pc.jpg
ManufacturerConvergent Technologies[1][2]
TypeProfessional Computer
Release dateMarch 26, 1985 (1985-03-26)[3]
Introductory priceUS$5,095 (equivalent to $12,300 in 2020) - US$7,290 (equivalent to $17,500 in 2020)[3][4]
Media5¼-inch floppy disks,[2] optional QIC tapes
Operating systemAT&T UNIX v3.51[1]
CPUMotorola 68010 with custom MMU clocked at 10 MHz[2]
Memory512 KB to 4 MB RAM[2]
StorageOptional 10 MB, 20 MB, 40 MB,[2] and 67 MB hard drives[1]
Display12 inches (30 cm), 720 x 348[2]
InputKeyboard, 3-button Mouse[2]
ConnectivityRS-232 port, Parallel port, 3 phone jacks
Mass40 lb (18 kg)

The AT&T UNIX PC is a Unix desktop computer originally developed by Convergent Technologies[2] (later acquired by Unisys),[1] and marketed by AT&T in the mid- to late-1980s. The system was codenamed "Safari 4"[5] 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.[6]

Hardware configuration[edit]

Exterior of the AT&T 3B1

PC 7300[edit]

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 was innovative, and in fact the machine gained notoriety appearing in many movies as the token "computer."[citation needed]

AT&T 3B1[edit]

A later enhanced model was renamed "3B1".[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]


Convergent Technologies offered an S/50 which was a re-badged PC 7300.[7]

Olivetti AT&T 3B1[edit]

British Olivetti released the "Olivetti AT&T 3B1 Computer" in Europe.[8]

Operating system[edit]

Video of an AT&T PC 7300 booting
AT&T PC 7300 compiling and running a C program

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]

Programming languages[edit]

Application software[edit]

  • SMART System (Office Suite)
  • dBASE III (DBM)[3]
  • Informix (DBM)
  • Oracle (DBM)
  • Paint Power (drawing package)
  • Sound Presentations (presentation graphics)[9]
  • Samna/AT&T Write Power 2 (word processor/spreadsheet)
  • Samna Plus (word processor/spreadsheet)[10]

Spreadsheet software[edit]

Word processors[edit]



Expansion cards[edit]

  • DOS-73 8086 co-processor card running at 8 MHz with 512 KB RAM, an RS-232 COM2 port and optional 8087 math co-processor chip. It included MS-DOS 3.1. This board was designed and built for AT&T by Alloy Computer Products of Framingham MA.
  • RAM card 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
  • 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".[14]
  • Floppy Tape card provided interface for 23 MB MFM Tape Cartridge Drive.
  • QIC-02 card for tape backup
  • Expansion chassis card was hard-wired to Expansion Chassis (with five added slots)

Public domain software[edit]

The Store is a public domain software repository which was available for all 3B1 users.[15]


The FreeBee emulator is available at FreeBee on GitHub.

See also[edit]


  1. ^ a b c d e f g h i j k l m n o p q r s t u v w x y z aa ab "3b1 FAQ". Retrieved 1 August 2019.
  2. ^ a b c d e f g h i j k l m n o p q r s Mayer, Alastair J. W. "System Review: The AT&T UNIX PC" (PDF). Byte. No. May 1986. pp. 254–262. Retrieved 2019-08-01.
  3. ^ a b c d e f g h i j k l m n Howitt, Doran (1984-04-08). "At Last, AT&T's 7300/Unix PC". Infoworld. p. 17. Retrieved 2019-08-01.
  4. ^ "AT&T Introduces Computer Gear Aimed at IBM-Led Office Market".
  5. ^ "NEW AT&T COMPUTER OFFICE GEAR". Chicago Tribune. March 27, 1985.
  6. ^ AT&T, Select Code 999-601-311IS, AT&T UNIX PC Owner's Manual (1986)
  7. ^ "Vendors of Multiuser Microcomputer Products". Infoworld. 1986-10-13.
  8. ^ "Olivetti Technical Specifications". Olivetti.
  9. ^ a b c d e Satchell, Stephen (1985-09-23). "A Look at Software for AT&T's Unix PC". Infoworld. pp. 32–33. Retrieved 2019-07-30.
  10. ^ "Samna Plans Unix-based Product Line". InfoWorld. June 16, 1986. p. 17.
  11. ^ "Games".
  12. ^ "Comp.sources.3b1 Archive Volume 1".
  13. ^ "Miscellaneous Software".
  14. ^ "AT&T System 25 Reference Manual" (1). September 1989. Cite journal requires |journal= (help)
  15. ^ "The STORE".

External links[edit]