Computer Closet Collection

[ Home | FAQ | News | Contents | Indexes ]

IBM PC 5150

See below for specifications and information on this system.

Key Dates:	September 1980 - The IBM PC "Dirty Dozen" design team is formed in IBM's obscure Boca Raton location. Some say this is for secrecy. The project is code name "Acorn" -- as in, from a tiny acorn grows... August 1981 - IBM announces the PC September 1981 - the IBM PC ships -- early!
Original Price:	$3000 with 64K and one floppy drive
CPU:	Intel 8088, 4.77 MHz
Memory:	16K, expandable to 64K on system board, up to 640K via add-in boards (later models had 256K RAM capacity on the system board)
Operating System:	IBM PC-DOS (Microsoft MS-DOS)
Input/Output:	Cassette port; optional internal 5 1/4" single-sided 160K floppy disk drives (later double-sided 360K)
Bus:	IBM PC bus
Other Items in Collection:	IBM PC Display in box; IBM PC Keyboard in box

The original IBM PC is the grandfather of today's most popular computers, which until recently were known as "IBM Compatibles" (now more frequently referred to as "x86 architecture" or "Windows PCs"). A modern Pentium II machine will still run programs written for the IBM PC more than 16 years ago. In fact, while the IBM PC bus is gradually being replaced with PCI (Peripheral Connection Interface), most modern PCs still accept ancient IBM expansion cards. Today, the original IBM PC bus is known as the "ISA", or Industry Standard Architecture, bus.

This photo shows the Computer Closet's complete IBM PC system, including the system unit (bottom), monochrome display (middle), and keyboard (top). All are in the original IBM boxes.

The IBM PC rapidly dominated the personal computing industry, despite some wacky marketing decisions by IBM such as licensing the Charlie Chaplin "Little Tramp" character as their advertising mascot, and the disastrous introduction of the PC's "little brother", the IBM PCjr.

Evolution of the IBM PC Architecture

1981 - IBM PC - 8088, 4.77 MHz
IBM XT - 8088, 4.77 MHz (adds a hard disk)
IBM AT - 80286, 6-8 MHz (the 286 breaks the "640K barrier", but only with a special "protected mode" in which normal programs won't run; a slot extension is added to bring the IBM PC bus to 16 bit width; hard disks are now supported in the system BIOS ROM)
Compaq Deskpro 386 - 80386, 16 MHz (along with ALR, the first non-IBM machines to introduce a new Intel architecture; memory management is now built-in; Windows 386, the first mass-market 80386 operating system, ships in the box with Compaq machines)
IBM PS/2 Model 80 - 80386, 16-25 MHz (introduces Micro Channel Architecture, which was doomed to failure due to IBM licensing fees; introduces hugely successful VGA graphics architecture)
Various manufacturers - 80486 (the "IBM compatible" market is now highly fragmented and IBM is no longer dominant)
Industry consortium introduces EISA bus as a replacement for the IBM PC architecture - it achieves limited acceptance in server platforms only
Video Electronics Standards Association industry consortium introduces VESA Local Bus - designed primarily for video cards and highly dependent on system speed, VLB is nonetheless the first local bus architecture on the market
Various manufacturers - Intel's new processor is called the Pentium instead of 586 due to their loss of copyright on the "x86" nomenclature
Intel introduces PCI (Peripheral Connection Interface) architecutre, which rapidly becomes the dominant system bus, although most machines still include some "ISA" slots
1996-1997 Various manufacturers - Intel Pentium Pro and Pentium II architecture
1997 - Intel introduces AGP (Advanced Graphics Port), yet another graphics-specific local bus technology for Pentium Pro/Pentium II machines. AGP ships in September 1997

Return to Computer Index