Alan Freedman -- The Computer Language Company - Computer Desktop Encyclopedia
Computer Desktop Encyclopedia
Longest-Running Tech Reference on the Planet

A CDE Definition

You'll love The Computer Desktop Encyclopedia (CDE) for Tech Term of the Day (TTOD)



A PC made by IBM. In 1981, the first IBM PC was introduced with a colossal 16KB of RAM. However, the company was not that optimistic, projecting that 250,000 IBM PCs would sell in the first five years. In fact, three million were sold in that period, and the PC industry, first DOS and later Windows, would become the world's largest computer base.

Good Bye IBM PC
In 2004, IBM exited the desktop and laptop arena when it sold its personal computer division to Lenovo, a major Chinese PC manufacturer. IBM retained its x86-based server market with its System x series until 2014, when Lenovo also acquired the line. See System x.

Names and Numbers
IBM's first PCs had names such as PC, XT and AT, while its next-generation PS/2 line was given model numbers. For historical purposes, early IBM model designations are listed below. See PC, IBM-compatible PC, ThinkPad, IBM and Lenovo.

The Original IBM PC
This first model had two floppy disks and 16KB of RAM. Today, a smartphone has 150,000 times as much memory and more. (Image courtesy of IBM.)

IBM PS/2 Model 50
The PS/2 introduced the Micro Channel bus, VGA graphics and the 3.5" floppy disk. See IBM PS/2. (Image courtesy of IBM.)

IBM ThinkPad
Very popular, IBM's ThinkPads introduced novel features such as the pointing stick and Butterfly keyboard. This model 755CD came out in 1994. See ThinkPad. (Image courtesy of IBM.)


 Model       Intro. CPU   Features

 PC (#1)     1981   8088  floppy disk
 XT          1983   8088  slow HD
 XT 286      1986    286  slow HD
 XT/370      1983   8088  370 emulation
 AT          1984    286  hard disk
 3270 PC     1983   8088  3270 emulation
 PCjr        1983   8088  floppy home use
 PC Portable 1984   8088  floppy portable
 Convertible 1986   8088  floppy laptop

 Unless otherwise noted, models
 used the Micro Channel bus.

 Model    Intro. CPU  Features

 25       1987   8086, PC bus
 30       1987   8086, PC bus
 30-286   1988   286, ISA bus
 35 LS    1991   386SX, ISA, diskless
 35 SX    1991   386SX, ISA
 L40 SX   1991   386SX, ISA, laptop
 40 SX    1991   386SX, ISA
 N45 SL          386SL notebook
 50       1987   286
 50 Z     1988   286, faster 50
 N51 SX   1992   386SX, notebook
 N51 SLC  1992   386SLC, notebook
 55 SX    1989   386SX
 55 LS    1990   386SX, diskless
 56 SLC   1992   386SLC
 56 SX    1992   386SX, upgradable
 57 SLC   1992   386SLC
 57 SX    1991   386SX, 2.88MB floppy
 CL57 SX  1992   386SX, notebook
 60       1987   286
 65       1990   386SX
 70       1988   386
 70 486   1989   486
 P70      1989   386 portable
 P75 486  1990   486 portable, 22 lbs.
 76       1994   486SX & DX, OS/2, SCSI
 76i      1994   486SX, OS/2, IDE drive
 77       1994   DX4, OS/2, SCSI, ECC RAM
 77i      1994   DX4, OS/2, IDE, ECC RAM
 80       1987   386, tower
 90       1990   486, XGA, SCSI
 90       1992   486DX2/66
 95       1990   486, tower
 90 SX    1991   486SX
 95 SX    1991   486SX, tower

Personal Use Only

Before/After Your Search Term
IBM cardIBM PC Company
IBM-compatible mainframeIBM Power Systems
IBM-compatible PCIBM PS/1
IBM formatIBM PS/2
IBM iIBM server series
IBM mainframesIBM SP
IBM midrange computersIBM workstation
IBM minicomputersIBMBIO.COM

Terms By Topic
Click any of the following categories for a list of fundamental terms.
Computer Words You Gotta KnowSystem design
Job categoriesUnix/Linux
Interesting stuffPersonal computers
InternetIndustrial Automation/Process Control
Communications & networkingAssociations/Standards organizations
HistoryDesktop publishing
ProgrammingHealthcare IT
System design