A portable computer is a computer designed to be easily moved from one place to another, as opposed to those designed to remain stationary at a single location such as desktops and workstations. These computers usually include a display and keyboard that are directly connected to the main case, all sharing a single power plug together, much like later desktop computers called all-in-ones (AIO) that integrate the system's internal components into the same case as the display. In modern usage, a portable computer usually refers to a very light and compact personal computer such as a laptop, subnotebook or handheld PC, while touchscreen-based handheld ("palmtop") devices such as tablets, phablets and smartphones are called mobile devices instead. Early major portables included the 50-pound (23 kg) IBM 5100 (1975), Osborne's 24-pound (11 kg) CP/M-based Osborne 1 (1981) and Compaq's 28-pound (13 kg), advertised as 100% IBM PC compatible Compaq Portable (1983). These luggable computers still required a continuous connection to an external power source; Laptop computers later overcame this limitation. Laptops were followed by lighter models such as netbooks, so that in the 2000s mobile devices and by 2007 smartphones made the term portable rather meaningless. The 2010s introduced wearable computers such as smartwatches. Portable computers, more narrowly defined, are distinct from desktop replacement computers in that they usually were constructed from full-specification desktop components, and often do not incorporate features associated with laptops or mobile devices. A portable computer in this usage, versus a laptop or other mobile computing device, has a standard motherboard or backplane providing plug-in slots for add-in cards. This allows mission-specific cards, such as test, A/D, or communication protocol (IEEE-488, 1553) to be installed. Portable computers also provide for more disk storage by using standard disk drives and provide for multiple drives.
Early history
Berkeley's Simon
The Simon, developed by Edmund Berkeley with help from a young Ivan Sutherland, was the first digital computer kit introduced to the public in 1951. Between 1949 and 1951, a series of instruction guides published in Radio-Electronics guided the reader in building a Simon at home for about $300, or about $3,810 in 2026. Despite an intention for portability, with assembly instructions suggesting the addition of a handle, the computer used electromechanical relays, and therefore was not an electronic computer in the modern sense.
Packard-Bell PB-250 The Packard Bell PB-250 was a very early minicomputer, with the ability to fit on top of a desk and similar dimensions to the 1965 DEC PDP-8, despite preceding the PDP-8 to the commercial market by 5 years. Often used for engineering work and industrial control systems, a pioneering feature of the PB-250 was its ability to run entirely off batteries for several hours, considered a first in the computer industry at the time. The PB-250 was also one of the lightest computers of the early 1960s, weighing in at only 110 pounds, less than half of the PDP-8's weight. By 1962, several van services had been established to provide mobile industrial control and quality assurance, using a PB-250 and accompanying analog computer, as well as various paper tape and punch inputs, to form an entirely functional, and rather mobile multi-purpose computer system in the back of a small van. A July 1962 article claimed that: "Even when the van is moving, the computer can be operated from a standard battery at peak performance."
Semiconductor Network Computer A very early experimental transistorized system, termed the Semiconductor Network Computer, was developed at Texas Instruments for use by the United States Air Force in the early 1960s. By 1961, they had shrunk down an entire digital computer to the size of a 10-oz, 6.3-in3 palm-sized package. However, this did not include any form of storage or I/O, and was intended for very specific military aerospace applications.
Hewlett-Packard 9830A One of the earliest contenders for a portable computer in the modern sense is Hewlett Packard's HP-9830A series of systems, introduced in late 1972. Despite often being referred to as "calculators," the December 1972 issue of the Hewlett Packard Journal states "It can be used as a desktop computer or a remote computer terminal, yet it maintains the convenience and user interaction of a programmable calculator," directly suggesting its use as a desktop computer. The unit included a one-line alphanumeric LED display, alphanumeric keyboard, up to 8k of RAM, and a built-in cassette drive. Each system also included BASIC resident in ROM, and an optional $25 carrying handle, facilitating portability. The base 4k RAM model cost $5,795 at launch, or about $11,300 in 2026.
MCM/70
After about 3 years of development, Micro Computer Machines of Ontario, Canada released the MCM/70 microcomputer in November of 1974, just ahead of the Altair 8800. Despite its weight of only 20 pounds and convenient size compared to other machines of the era, there is no indication it was primarily meant as a portable, unlike the HP-9830A and similar systems which were specifically marketed as such (and included carrying handles).
SCAMP In 1973, the IBM Los Gatos Scientific Center developed a portable computer prototype called SCAMP (Special Computer APL Machine Portable) based on the IBM PALM processor with a Philips compact cassette drive, small CRT and full-function keyboard. SCAMP emulated an IBM 1130 minicomputer in order to run APL\1130. In 1973, APL was generally available only on mainframe computers, and most desktop-sized microcomputers such as the Wang 2200 or HP 9800 offered only BASIC. Because SCAMP was the first to emulate APL\1130 performance on a portable, single user computer, PC Magazine in 1983 designated SCAMP a "revolutionary concept" and "the world's first personal computer". The engineering prototype is in the Smithsonian Institution.
Xerox NoteTaker Xerox NoteTaker, developed in 1976 at Xerox PARC, was a precursor to later portable computers from Osborne Computer Corporation and Compaq, though it remained a prototype and did not enter production.
IBM 5100
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