---
title: IBM RT (6150)
categories:
- Computers
types:
- Professional Computer
origins:
- U.S.A.
years:
- '1986'
cpus:
- ROMP RISC processor
params:
  name: RT (6150)
  image: /media/museum/photos/ibm_6150_system_1.jpg
  company: /companies/ibm
  company_name: IBM
  specs:
  - label: NAME
    value: RT (6150)
  - label: MANUFACTURER
    value: IBM
  - label: TYPE
    value: Professional Computer
  - label: ORIGIN
    value: U.S.A.
  - label: YEAR
    value: late 1986
  - label: BUILT IN LANGUAGE
    value: None
  - label: KEYBOARD
    value: Special RT 102-key keyboard, PC-AT layout.
  - label: CPU
    value: ROMP RISC processor
  - label: SPEED
    value: 5.88, 10 or 12.5 MHz (170, 100 or 80ns cycle time)
  - label: CO-PROCESSOR
    value: Memory Management Unit (MMU), optional 20 MHz Motorola 68881 Math coprocessor
  - label: RAM
    value: From 1 MB to 16 MB
  - label: ROM
    value: Unknown
  - label: TEXT MODES
    value: 80 chars. x 25 lines
  - label: GRAPHIC MODES
    value: 720 x 512 (mono or colour), 1024 x 768 (mono)
  - label: COLORS
    value: '16'
  - label: SOUND
    value: Beeper
  - label: SIZE / WEIGHT
    value: Unknown
  - label: I/O PORTS
    value: 2 x serial ports
  - label: BUILT IN MEDIA
    value: |-
      1 or 2 5.25'' 1.2 MB floppy disc drives\
      Up to three 40 MB or 70 MB hard disks
  - label: OS
    value: AIX, based on Unix System V, MS-DOS 3.2
  - label: POWER SUPPLY
    value: Built-in power supply unit
  - label: PRICE
    value: From £9800
  tabs:
  - photos
  forum_thread: 848
  photos:
  - title: BACK SIDE
    subtitle: ''
    text: No doubt, the 6150 hardware is very reliable and designed for a long use.
    image: /media/museum/photos/ibm_6150_back_1.jpg
  oc_id: 867
  source:
    url: https://web.archive.org/web/20230609145511/http://www.old-computers.com/museum/computer.asp?c=867
    date: '2023-06-09'
---

The IBM RT (or PC/RT or 6150 in Europe) was a 32-bit RISC machine. In fact 'RT' meant 'RISC Technology' where RISC itself was initials of **R**educed **I**nstruction **S**et **C**omputers. This machine was IBM's first try into the single-user workstation world and was the ancestor of the RS/6000 range.

The advantages of RISC technology were smaller processor chips, since they needed less on-chip storage for the instruction set, faster signal transfer between devices, and faster instruction execution since the reduced set was designed so that most instructions was executed in a single clock cycle.

The RISC processor of the 6150 was called ROMP for **R**eshearch **O**ffice **P**roducts **D**ivision. Its study started in IBM Texas labs in 1977 and a prototype form ran in 1978

There were two RT models, the floor-standing 6150 and the desktop 6151. The differences between them lie in the positioning of some I/O ports and in the storage options available. Despite processor incompatibility with MS-DOS software, the 6150 could run PC software thanks to a PC expansion card holding a Intel 80286 and designed to fit in one of the AT compatible slots of the 6150. the motherboard featured four 32-bit expansion slots to hold the ROMP board, an optional floating-point accelerator board, and two 2 MB RAM boards; two 8-bit and six 16-bit PC slots.

The 6150 operating system was called AIX for **A**dvanced **I**nteractive e**X**ecutive. It succeded to IBM OSes. In fact, it was just an Unix System V with Berkeley 4.2 enhancements and IBM adds for the 6150 environment. Among these adds, the VRM (**V**irtual **R**essource **M**anager) handled the interface between the Unix kernel and the specific 6150 harware it ran on. A DOS shell was also provided for MS-DOS applications.

Nowadays, one finds RISC processors mainly in numerous small devices like PalmTops or mobile phones. Apple and IBM also use them today, the biggest examples being the PowerPC 7455 (G4) and PowerPC G5 Processor, mostly used in the Power Macintosh and Powerbook series of computers. Many Proprietary Unix systems used them up until only a few years ago (Sun, Silicon Graphics).