Released in August 1981, the IBM Personal Computer was IBM’s first microcomputer and the hardware platform that created the standard for PC compatibles. The IBM PC used an open architecture and the PC-DOS from Microsoft. Later, in 1984, IBM released the considerably improved IBM AT based on 80286 and a 16-bit AT bus.
International Business Machines Corporation (IBM)
In the early 80s, IBM was already established as the leader in high-end business solutions by supplying mainframes to large corporations and governments. The platform System/360 dominated the mainframe market from 1965 until the late 70s. Notable IBM inventions include magnetic tape drives, random access memory (RAM), floppy and hard disk drives, the SQL language, and the ATM machine.
Table: Early series of IBM Personal Computers
The IBM PC
The IBM PC aimed to compete against companies like Apple, Commodore, and Tandy for a market share in the newly-created and promising personal computer market. That market was worth 15 billion dollars at the time, with an estimated growth rate of 30-40% for the following years. In order to achieve a quick entrance into the market, IBM almost bought Atari, however, they decided to form a new independent department for the development of personal computers. The motherboard was designed in 40 days, and after four months, a working prototype was ready.
The IBM PC proved a tremendous success, selling over 750,000 units until 1983, exceeding IBM’s wildest estimates. Earlier, in mid-1982, the first PC compatibles were released. IBM didn’t see that coming.
- The IBM PC had a price tag of $1,565 ($4,980 in today’s money)
- The standard configuration included the 8088 CPU at 4.7 MHz, CGA graphics adapter, 16 kB of RAM, an 83-key keyboard, and no disk drives
- 8-bit expansion cards
Operating System of the IBM PC
Initially, IBM planned to support several operating systems such as the CP/M-86 and the PC DOS by Microsoft. However, PC DOS (MS-DOS) was already complete, and IBM chose to use it as the standard OS for their PC.
- PC DOS version 1.00
Released in 1984, the IBM/AT (model 5170) is a considerably improved computer based on the 80286 CPU by Intel.
- 80286 CPU, optional the 80287 FPU
- PC DOS 3.0 (supporting networking)
- MDA, CGA, EGA, or PGA video cards
- 20 MB hard disk drive (standard)
- 5+1⁄4 inch (1.2 MB) floppy disk drive
- 16-bit AT bus (ISA) offering backward compatibility with 8-bit expansion cards
- RAM capacity up to 16 MB
- Battery-backed clock (RTC)
- AT keyboard (84-key layout, later AT models included 101-key keyboards)
The success of IBM AT created the market for lower-priced compatible systems. Popular AT clones included the Compaq Deskpro, HP Vectra, Zenith Z-286, Commodore PC-30, and Tandy 3000.
IBM PCjr (PC JUNIOR)
Released in March 1984, the IBM PCjr is a home computer that was manufactured by IBM until May 1985. The computer featured better graphics and sound.
- Priced $1,269 ($3,700 in today’s money)
- PC DOS 2.10 Operating System
- 8088 CPU at 4.77 MHz
- 128 kB of RAM (not capable of supporting decent gaming)
- 5.25" (360 KB) disk drive
- 320x200 resolution with 16 colors
- Enhanced sound with the Texas Instruments SN76496 chip (can produce three square waves)
- Built-in joystick ports
- Composite video out (TV)
- Infrared wireless keyboard
Released in 1987, the IBM PS/2 (Personal System/2) replaced the first generation of IBM personal computers (PC, XT, AT). The PS/2 included several innovations such as the VGA card and the 1.44 MB disk drive (optional). With 256 KB video memory, the VGA adapter provided significantly improved graphics for apps and games:
- 640×480 with 16 colors
- 320×200 with 256 colors
- 262,144 colors palette
- After 18 months, IBM reported that it had sold 3 million PS/2 units.
- Software-compatible PC/AT/XT
- 80286-80486 CPU
- IBM PC DOS 3.3, and later the OS/2 operating system
- VGA (Video Graphics Array) standard
- 1.44 MB 3.5-inch floppy disk drive (not all models)
- PS/2 ports (mouse/keyboard)
- 101-key keyboard layout
Released in 1990, the IBM PS/1 (Personal System/1) was the second IBM attempt to gain a share in the promising home computing market. The system was abandoned in 1994 for IBM Aptiva. With the PC Junior, the 80286 PS/1 was sold at a lower price tag ($1,699 in 1990 or $3,760 in today’s money).
- PC DOS 4.01
- 80286-80486DX CPU
- 512 KB to 2.5 MB of RAM
- VGA Graphics
- A modem installed
■ IBM Personal Computers
Sources: Wikipedia, IBM