IBM RT
Encyclopedia
The IBM RT was a computer workstation sold by IBM
and based around IBM's ROMP
processor
, a spin-off of the IBM 801
pioneered at IBM Research. The system was introduced in 1986
as the RT PC (RISC Technology Personal Computer) and ran AIX
1.x and 2.x, the Academic Operating System
(AOS), or the Pick operating system
. It was commonly, but incorrectly, known as the PC RT, and IBM later simplified the name. It didn't enjoy much success, and all models were discontinued by May 1991. However, the system spurred further development, as it was followed by IBM's RS/6000
and the corresponding POWER
processor line, which was the basis for the PowerPC
.
There were three versions of the 6150/6151 processor card: the standard 032 processor card had a 5.9 MHz clock rate, 1 MB
standard memory (expandable via 1 MB, 2 MB or 4 MB memory boards) and optional floating point
accelerator.
The Advanced processor card had a 10 MHz clock and either 4 MB memory on the processor card, or external 4 MB ECC memory cards, and featured a built-in 20 MHz Motorola 68881
floating-point processor. The Enhanced Advanced processor card had a cycle time of 80ns, 16 MB on-board memory, while an enhanced advanced floating point accelerator was standard.
I/O was provided by eight ISA bus slots. A typically configured RT came with 4 MB of memory, maxing out at 16 MB, and with a 40 or 70 MB hard drive, upgradable to 300 MB or more with external SCSI
cabinets. Also standard were mouse and either a 720×512 or 1024×768 pixel-addressable display and either a 4 MB/s Token Ring network adapter, or a 10Base2
Ethernet
adapter.
The IBM 6152 was a hybrid IBM PS/2 Model 60 with a special MicroChannel
board version of the 032 processor, dubbed a "crossbow" board. It ran only the AOS operating system, downloaded from another IBM 6150 or 6151 also running AOS, via a LAN
TCP/IP interface.
. The keyboard, mouse, display, disk drives and network were all controlled by a microkernel, called Virtual Resource Manager (VRM), which allowed multiple operating systems to be booted and run at the same time. One could "hotkey" from one operating system to the next using the Alt-Tab key combination. Each OS in turn would get possession of the keyboard, mouse and display. Both AIX version 2 and the Pick operating system were ported to this microkernel. Pick was unique in being a unified operating system and database, and ran various accounting applications. It was popular with retail merchants, and accounted for about 4,000 units of sales.
The primary operating system for the RT was AIX version 2. Much of the AIX v2 kernel was written in a variant of the PL/I
programming language, which proved troublesome during the migration to AIX v3. AIX v2 included full TCP/IP networking support, as well as SNA, and two networking file systems: NFS, licensed from Sun Microsystems
, and Distributed Services or DS. DS had the distinction of being built on top of SNA, and thereby being fully compatible with DS on the IBM midrange AS/400 and mainframe systems. For the graphical user interfaces, AIX v2 came with the X10R3 and later the X10R4 and X11 releases of the X Window System
from MIT, together with the Athena widget set
. Compilers for Fortran
and C were available.
Some RT-PCs were also shipped with AOS
, an IBM port of 4.3BSD
to the ROMP.
The RT forced an important stepping-stone in the development of the X Window System, when a group at Brown University
ported X version 9 to the system. Problems with reading unaligned data on the RT forced an incompatible protocol change, leading to version 10 in late 1985.
line of computers. This confusion started with its initial name, "IBM RT PC". Initially, it seemed that even IBM thought that it was a high end Personal Computer given the initially stunning lack of support that it received from IBM. This could be explained by the sales commission structure the IBM gave the system: salesmen received commissions similar to those for the sale of a PC: not much. With typically configured models priced at $20,000, it was a hard sell, and so the lack of any reasonable commission resulted in a loss of interest by the IBM sales force.
The performance of the RT, in comparison with other contemporaneous Unix workstations, was not outstanding. In particular, the floating point
performance was poor, and was scandalized mid-life with the discovery of a bug in the floating point square root routine.
With the RT system's modest processing power (when first announced), and with announcements later that year by some other workstation vendors, industry analysts questioned IBM's directions. AIX for the RT was IBM's second foray into UNIX
. (After PC/IX in September 1984.)The lack of software packages and IBM's sometimes lackluster support of AIX, plus the sometimes unusual changes from traditional UNIX operating system defacto standards caused most software suppliers to be slow to embrace the RT and AIX. The RT found its home mostly in the CAD
/CAM
and CATIA
areas, with some inroads into the scientific and educational areas, especially after the announcement of AOS and substantial discounts for the educational community. The RT running the Pick OS also found use as shopping store control systems, given the strong database, accounting system and general business support in the Pick OS. The RT also did well as an interface system between IBM's larger mainframes, due to its SNA and DS support, and some of its point of sale terminals, store control systems and also machine shop control systems.
Approximately 23,000 RTs were sold over the lifetime of the product, with some 4,000 going into IBM internal development and sales organizations. Pick OS sales accounted for about 4,000 units of sales.
This entry incorporates text from the RT/PC FAQ .
IBM
International Business Machines Corporation or IBM is an American multinational technology and consulting corporation headquartered in Armonk, New York, United States. IBM manufactures and sells computer hardware and software, and it offers infrastructure, hosting and consulting services in areas...
and based around IBM's ROMP
ROMP
The ROMP or Research Micro Processor was a 10 MHz RISC microprocessor designed by IBM in the early 1980s manufactured on a 2 µm process with 45,000 transistors....
processor
Central processing unit
The central processing unit is the portion of a computer system that carries out the instructions of a computer program, to perform the basic arithmetical, logical, and input/output operations of the system. The CPU plays a role somewhat analogous to the brain in the computer. The term has been in...
, a spin-off of the IBM 801
IBM 801
The 801 was an experimental minicomputer designed by IBM. The resulting architecture was used in various roles in IBM until the 1980s. The 801 was started as a pure research project led by John Cocke in October 1975 at the Thomas J. Watson Research Center. The name 801 comes from the building the...
pioneered at IBM Research. The system was introduced in 1986
1986 in science
The year 1986 in science and technology involved many significant events, some listed below.-Astronomy and space exploration:* January 24 – Voyager 2 space probe makes first encounter with Uranus....
as the RT PC (RISC Technology Personal Computer) and ran AIX
AIX operating system
AIX AIX AIX (Advanced Interactive eXecutive, pronounced "a i ex" is a series of proprietary Unix operating systems developed and sold by IBM for several of its computer platforms...
1.x and 2.x, the Academic Operating System
Academic Operating System
Academic Operating System was IBM's version of 4.3BSD Unix for the IBM RT. It was offered to academic institutions as an alternative to AIX, the usual RT operating system....
(AOS), or the Pick operating system
Pick operating system
The Pick operating system is a demand-paged, multiuser, virtual memory, time-sharing operating system based around a unique "multivalued" database. Pick is used primarily for business data processing...
. It was commonly, but incorrectly, known as the PC RT, and IBM later simplified the name. It didn't enjoy much success, and all models were discontinued by May 1991. However, the system spurred further development, as it was followed by IBM's RS/6000
RS/6000
RISC System/6000, or RS/6000 for short, is a family of RISC and UNIX based servers, workstations and supercomputers made by IBM in the 1990s. The RS/6000 family replaced the IBM RT computer platform in February 1990 and was the first computer line to see the use of IBM's POWER and PowerPC based...
and the corresponding POWER
IBM POWER
POWER is a reduced instruction set computer instruction set architecture developed by IBM. The name is an acronym for Performance Optimization With Enhanced RISC....
processor line, which was the basis for the PowerPC
PowerPC
PowerPC is a RISC architecture created by the 1991 Apple–IBM–Motorola alliance, known as AIM...
.
Hardware
Three models were produced, the 6150, 6151, and 6152. The basic types of machines were the tower model (6150), and the desktop model (6151). All these models featured a special board slot for the processor card, as well as machine specific RAM cards. Each machine had one processor slot, one co-processor slot, and two RAM slots.There were three versions of the 6150/6151 processor card: the standard 032 processor card had a 5.9 MHz clock rate, 1 MB
Megabyte
The megabyte is a multiple of the unit byte for digital information storage or transmission with two different values depending on context: bytes generally for computer memory; and one million bytes generally for computer storage. The IEEE Standards Board has decided that "Mega will mean 1 000...
standard memory (expandable via 1 MB, 2 MB or 4 MB memory boards) and optional floating point
Floating point
In computing, floating point describes a method of representing real numbers in a way that can support a wide range of values. Numbers are, in general, represented approximately to a fixed number of significant digits and scaled using an exponent. The base for the scaling is normally 2, 10 or 16...
accelerator.
The Advanced processor card had a 10 MHz clock and either 4 MB memory on the processor card, or external 4 MB ECC memory cards, and featured a built-in 20 MHz Motorola 68881
Motorola 68881
The Motorola 68881 and Motorola 68882 were floating-point coprocessor chips that were used in some computer systems in conjunction with the 68020 or 68030 CPUs. The addition of one of these chips added substantial cost to the computer, but added a floating point unit that could rapidly perform...
floating-point processor. The Enhanced Advanced processor card had a cycle time of 80ns, 16 MB on-board memory, while an enhanced advanced floating point accelerator was standard.
I/O was provided by eight ISA bus slots. A typically configured RT came with 4 MB of memory, maxing out at 16 MB, and with a 40 or 70 MB hard drive, upgradable to 300 MB or more with external SCSI
SCSI
Small Computer System Interface is a set of standards for physically connecting and transferring data between computers and peripheral devices. The SCSI standards define commands, protocols, and electrical and optical interfaces. SCSI is most commonly used for hard disks and tape drives, but it...
cabinets. Also standard were mouse and either a 720×512 or 1024×768 pixel-addressable display and either a 4 MB/s Token Ring network adapter, or a 10Base2
10BASE2
10BASE2 is a variant of Ethernet that uses thin coaxial cable , terminated with BNC connectors...
Ethernet
Ethernet
Ethernet is a family of computer networking technologies for local area networks commercially introduced in 1980. Standardized in IEEE 802.3, Ethernet has largely replaced competing wired LAN technologies....
adapter.
The IBM 6152 was a hybrid IBM PS/2 Model 60 with a special MicroChannel
Microchannel
Microchannel can refer to* Basic structure used in microtechnology, see Microchannel .* Micro Channel architecture in computing...
board version of the 032 processor, dubbed a "crossbow" board. It ran only the AOS operating system, downloaded from another IBM 6150 or 6151 also running AOS, via a LAN
Län
Län and lääni refer to the administrative divisions used in Sweden and previously in Finland. The provinces of Finland were abolished on January 1, 2010....
TCP/IP interface.
Software
One of the novel aspects of the RT design was the use of a microkernelMicrokernel
In computer science, a microkernel is the near-minimum amount of software that can provide the mechanisms needed to implement an operating system . These mechanisms include low-level address space management, thread management, and inter-process communication...
. The keyboard, mouse, display, disk drives and network were all controlled by a microkernel, called Virtual Resource Manager (VRM), which allowed multiple operating systems to be booted and run at the same time. One could "hotkey" from one operating system to the next using the Alt-Tab key combination. Each OS in turn would get possession of the keyboard, mouse and display. Both AIX version 2 and the Pick operating system were ported to this microkernel. Pick was unique in being a unified operating system and database, and ran various accounting applications. It was popular with retail merchants, and accounted for about 4,000 units of sales.
The primary operating system for the RT was AIX version 2. Much of the AIX v2 kernel was written in a variant of the PL/I
PL/I
PL/I is a procedural, imperative computer programming language designed for scientific, engineering, business and systems programming applications...
programming language, which proved troublesome during the migration to AIX v3. AIX v2 included full TCP/IP networking support, as well as SNA, and two networking file systems: NFS, licensed from Sun Microsystems
Sun Microsystems
Sun Microsystems, Inc. was a company that sold :computers, computer components, :computer software, and :information technology services. Sun was founded on February 24, 1982...
, and Distributed Services or DS. DS had the distinction of being built on top of SNA, and thereby being fully compatible with DS on the IBM midrange AS/400 and mainframe systems. For the graphical user interfaces, AIX v2 came with the X10R3 and later the X10R4 and X11 releases of the X Window System
X Window System
The X window system is a computer software system and network protocol that provides a basis for graphical user interfaces and rich input device capability for networked computers...
from MIT, together with the Athena widget set
Xaw
Xaw is short for the X Window System Athena widget set, which is a set of widgets to implement simple user interfaces based upon the X Toolkit Intrinsics...
. Compilers for Fortran
Fortran
Fortran is a general-purpose, procedural, imperative programming language that is especially suited to numeric computation and scientific computing...
and C were available.
Some RT-PCs were also shipped with AOS
Academic Operating System
Academic Operating System was IBM's version of 4.3BSD Unix for the IBM RT. It was offered to academic institutions as an alternative to AIX, the usual RT operating system....
, an IBM port of 4.3BSD
Berkeley Software Distribution
Berkeley Software Distribution is a Unix operating system derivative developed and distributed by the Computer Systems Research Group of the University of California, Berkeley, from 1977 to 1995...
to the ROMP.
The RT forced an important stepping-stone in the development of the X Window System, when a group at Brown University
Brown University
Brown University is a private, Ivy League university located in Providence, Rhode Island, United States. Founded in 1764 prior to American independence from the British Empire as the College in the English Colony of Rhode Island and Providence Plantations early in the reign of King George III ,...
ported X version 9 to the system. Problems with reading unaligned data on the RT forced an incompatible protocol change, leading to version 10 in late 1985.
Sales and market reception
The IBM RT had a varied life even from its initial announcement. Most industry watchers considered the RT as "not enough power, too high a price, and too late". Many thought that the RT was part of IBM's Personal ComputerIBM PC
The IBM Personal Computer, commonly known as the IBM PC, is the original version and progenitor of the IBM PC compatible hardware platform. It is IBM model number 5150, and was introduced on August 12, 1981...
line of computers. This confusion started with its initial name, "IBM RT PC". Initially, it seemed that even IBM thought that it was a high end Personal Computer given the initially stunning lack of support that it received from IBM. This could be explained by the sales commission structure the IBM gave the system: salesmen received commissions similar to those for the sale of a PC: not much. With typically configured models priced at $20,000, it was a hard sell, and so the lack of any reasonable commission resulted in a loss of interest by the IBM sales force.
The performance of the RT, in comparison with other contemporaneous Unix workstations, was not outstanding. In particular, the floating point
Floating point
In computing, floating point describes a method of representing real numbers in a way that can support a wide range of values. Numbers are, in general, represented approximately to a fixed number of significant digits and scaled using an exponent. The base for the scaling is normally 2, 10 or 16...
performance was poor, and was scandalized mid-life with the discovery of a bug in the floating point square root routine.
With the RT system's modest processing power (when first announced), and with announcements later that year by some other workstation vendors, industry analysts questioned IBM's directions. AIX for the RT was IBM's second foray into UNIX
Unix
Unix is a multitasking, multi-user computer operating system originally developed in 1969 by a group of AT&T employees at Bell Labs, including Ken Thompson, Dennis Ritchie, Brian Kernighan, Douglas McIlroy, and Joe Ossanna...
. (After PC/IX in September 1984.)The lack of software packages and IBM's sometimes lackluster support of AIX, plus the sometimes unusual changes from traditional UNIX operating system defacto standards caused most software suppliers to be slow to embrace the RT and AIX. The RT found its home mostly in the CAD
Computer-aided design
Computer-aided design , also known as computer-aided design and drafting , is the use of computer technology for the process of design and design-documentation. Computer Aided Drafting describes the process of drafting with a computer...
/CAM
Computer-aided manufacturing
Computer-aided manufacturing is the use of computer software to control machine tools and related machinery in the manufacturing of workpieces. This is not the only definition for CAM, but it is the most common; CAM may also refer to the use of a computer to assist in all operations of a...
and CATIA
CATIA
CATIA is a multi-platform CAD/CAM/CAE commercial software suite developed by the French company Dassault Systemes...
areas, with some inroads into the scientific and educational areas, especially after the announcement of AOS and substantial discounts for the educational community. The RT running the Pick OS also found use as shopping store control systems, given the strong database, accounting system and general business support in the Pick OS. The RT also did well as an interface system between IBM's larger mainframes, due to its SNA and DS support, and some of its point of sale terminals, store control systems and also machine shop control systems.
Approximately 23,000 RTs were sold over the lifetime of the product, with some 4,000 going into IBM internal development and sales organizations. Pick OS sales accounted for about 4,000 units of sales.
External links
- IBM RT PC-page
- The IBM RT Information Page
- JMA Systems's FAQ Archive
- comp.sys.ibm.pc.rt FAQ (as of 1994), archived at Giessen University
- [ftp://ftp-rt.dementia.org/pub/rt/ ftp-rt.dementia.org]
This entry incorporates text from the RT/PC FAQ .