The Osborne 1, the first successful portable computer, is unveiled at the West Coast Computer Faire in San Francisco.

The Osborne 1 is the first commercially successful portable computer, released on April 3, 1981 by Osborne Computer Corporation. It weighs 24.5 lb (11.1 kg), cost US$1,795, and runs the CP/M 2.2 operating system. It is powered from a wall socket, as it has no on-board battery, but it is still classed as a portable device since it can be hand-carried when the keyboard is closed.

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.

The West Coast Computer Faire was an annual computer industry conference and exposition most often associated with San Francisco, its first and most frequent venue. The first fair was held in 1977 and was organized by Jim Warren and Bob Reiling. At the time, it was the biggest computer show in the world, intended to popularize the personal computer in the home. The West Coast PC Faire was formed to provide a more specialized show. However, Apple Inc. stopped exhibiting at the West Coast Computer Faire, refusing to exhibit at any show other than COMDEX that also had PC-based exhibits.

San Francisco, officially the City and County of San Francisco, is a commercial, financial, and cultural center of Northern California. With a population of 827,526 residents as of 2024, San Francisco is the fourth-most populous city in the U.S. state of California and the 17th-most populous in the United States. San Francisco has a land area of 46.9 square miles at the upper end of the San Francisco Peninsula and is the fifth-most densely populated U.S. county. Among U.S. cities proper with over 250,000 residents, San Francisco is ranked first by per capita income and sixth by aggregate income as of 2023. San Francisco anchors the 13th-most populous metropolitan statistical area in the U.S., with almost 4.6 million residents in 2023. The larger San Jose–San Francisco–Oakland combined statistical area, the fifth-largest urban region in the U.S., had a 2023 estimated population of over nine million.