The 5150 could not itself power hard drives without retrofitting a stronger power supply, but IBM later offered the 5161 Expansion Unit, which not only provided more expansion slots, but also included a 10 MB ( later 20 MB ) hard drive powered by the 5161's own separate 130-watt power supply.

Space permitting, these could be installed into either the IBM PC's Expansion Unit, into PSU-upgraded PCs or into XTs.

Expansion cards for the Micro Channel bus typically targeted high-end graphic workstation or server requirements, with SCSI, Ethernet, IBM 5250 and IBM 3270 connections.

* ISRLEMX, the ISPF Member Expansion utility that is used on IBM mainframes

Famous 1980s expanded memory boards were AST RAMpage, IBM PS / 2 80286 Memory Expansion Option, AT & T Expanded Memory Adapter and the Intel Above Board.

* IBM 1826 I / O Expansion Chassis ( used for communications I / O, System / 360 channels, 279x )

* IBM 1828 Process Expansion Unit ( used for additional D / A or A / D converters, or to hold 1851 and / or 1854 multiplexors ; there was an RPQ for a remote 1828 unit )

Version 4. 03 supports IBM Memory Expansion Option boards with 2-8MB memory.

ISRLEMX is the ISPF Member Expansion utility used in IBM mainframes.

A meteorologist at the console of the IBM 7090 in the Joint Numerical Weather Prediction Unit.

The other nine units in ENIAC were the Initiating Unit ( which started and stopped the machine ), the Cycling Unit ( used for synchronizing the other units ), the Master Programmer ( which controlled " loop " sequencing ), the Reader ( which controlled an IBM punched card reader ), the Printer ( which controlled an IBM punched card punch ), the Constant Transmitter, and three Function Tables.

From the left: IBM 1402 | 1402 Card Read-Punch, 1401 Processing Unit, IBM 1403 | 1403 Printer.

The zone bits of the low-order character specified increments of 4000, 8000, or 12000, to address 16, 000 memory locations ( with an IBM 1406 Storage Unit ).

* System Reference Manual for the IBM 1620 Central Processing Unit, Model 2 ( PDF )

This family of " warehouse appliance-like " systems was given the name IBM Balanced Configuration Unit, or BCU, and is aimed at the warehouse appliance market typified by Netezza and DATAllegro, but it differentiates itself in that it uses the full-featured version of DB2 instead of a single-purpose warehouse-oriented RDBMS.

* Console Unit ( IBM 650 )

* Power Unit ( IBM 655 )

* Card Reader / Punch Unit ( IBM 533 or IBM 537 )

* Disk Unit ( IBM 355 ) Systems with a disk unit were known as a IBM RAMAC 650 Data Processing System

* Card Reader Unit ( IBM 543 )

* Card Punch Unit ( IBM 544 )

* Control Unit ( IBM 652 ) Magnetic Tape Controller

* Auxiliary Unit ( IBM 653 ) Core storage, index registers, floating point arithmetic

* Auxiliary Alphabetic Unit ( IBM 654 )

* Magnetic Tape Unit ( IBM 727 )

Primary user input was decimal, via standard IBM 80 column punched cards and output was decimal, via a front panel display.

It was also a less expensive alternative to the Apple Macintosh and IBM PC as a general-purpose business or home computer.

* Attached Support Processor, one of the two early IBM System / 360 programs that replaces the native SPOOL facilities of OS / 360 ; the other was Houston Automatic Spooling Priority ( HASP ).

AIX was the first operating system to utilize journaling file systems, and IBM has continuously enhanced the software with features like processor, disk and network virtualization, dynamic hardware resource allocation ( including fractional processor units ), and reliability engineering ported from its mainframe designs.

AIX Version 1, introduced in 1986 for the IBM 6150 RT workstation, was based on UNIX System V Releases 1 and 2.

A beta test version of AIX 5L for IA-64 systems was released, but according to documents released in the SCO v. IBM lawsuit, less than forty licenses for the finished Monterey Unix were ever sold before the project was terminated in 2002.

IBM maintains that their license was irrevocable, and continued to sell and support the product until the litigation was adjudicated.

AIX was a component of the 2003 SCO v. IBM lawsuit, in which the SCO Group filed a lawsuit against IBM, alleging IBM contributed SCO's intellectual property to the Linux codebase.

The original AIX ( sometimes called AIX / RT ) was developed for the IBM 6150 RT workstation by IBM in conjunction with Interactive Systems Corporation, who had previously ported UNIX System III to the IBM PC for IBM as PC / IX.

This was based on a design pioneered at IBM Research ( the IBM 801 ).

AIX PS / 2 ( also known as AIX / 386 ) was developed by Locus Computing Corporation under contract to IBM.

AIX / 370 was released in 1990 with functional equivalence to System V Release 2 and 4. 3BSD as well as IBM enhancements.

This development effort was made partly to allow IBM to compete with Amdahl UTS.

As an example, if one was trying to profit from a price discrepancy between IBM on the NYSE and IBM on the London Stock Exchange, they may purchase a large number of shares on the NYSE and find that they cannot simultaneously sell on the LSE.

The encoding of data by discrete bits was used in the punched cards invented by Basile Bouchon and Jean-Baptiste Falcon ( 1732 ), developed by Joseph Marie Jacquard ( 1804 ), and later adopted by Semen Korsakov, Charles Babbage, Hermann Hollerith, and early computer manufacturers like IBM.

* 1981 – The IBM Personal Computer is released.

Originally released for the IBM 6150 RISC workstation, AIX now supports or has supported a wide variety of hardware platforms, including the IBM RS / 6000 series and later IBM POWER and PowerPC-based systems, IBM System i, System / 370 mainframes, PS / 2 personal computers, and the Apple Network Server.

AIX PS / 2, first released in 1989, ran on IBM PS / 2 personal computers with Intel 386 and compatible processors.

Versions were also released for the IBM PC and compatibles, and the Apple IIGS.

In the meantime IBM had released its original IBM PC, which incidentally looked remarkably like the Asters base with floppy drives + separate keyboard set-up.

Only Larry Ellison's Oracle started from a different chain, based on IBM's papers on System R, and beat IBM to market when the first version was released in 1978.

An Ethernet adapter card for the IBM PC was released in 1982 and by 1985, 3Com had sold 100, 000.

In 1987, IBM released the PS / 2 line of computers, which included the MCA bus.

It was later ported to the IBM PC and released when the PC was announced in 1981.

After an interim 1. 3 version to fix up many remaining problems with the 1. x series, IBM released OS / 2 version 2. 0 in 1992.

Even though Microsoft released a cheap version of Adventure with its initial version of MS-DOS 1. 0 for IBM PCs, Zork I was still a popular seller for the PC, thanks to the superior quality of its writing and packaging.

A desk size machine with a different instruction set, the IBM 1130, was released concurrently with the System / 360 to address the niche occupied by the 1620.

While it was technically possible to retrofit more advanced floppy drives such as the high-density drive ( released in 1984 ) into the original IBM PC, this was not an option offered by IBM for the 5150 model, and the move to high-density 5. 25-inch floppies in particular was notoriously fraught with disk compatibility problems.

The Intel 8088, released in 1979, was a slightly modified chip with an external 8-bit data bus ( allowing the use of cheaper and fewer supporting logic chips ), and is notable as the processor used in the original IBM PC.

A version of the IBM PC called the 3270 PC, released in October 1983, included 3270 terminal emulation.

* 1986 – The first IBM PC computer virus is released into the wild.