14 Facts About Xerox Alto


Xerox Alto is a computer designed from its inception to support an operating system based on a graphical user interface, later using the desktop metaphor.

FactSnippet No. 507,819

Xerox Alto is contained in a relatively small cabinet and uses a custom central processing unit built from multiple SSI and MSI integrated circuits.

FactSnippet No. 507,820

Xerox Alto became well known in Silicon Valley and its GUI was increasingly seen as the future of computing.

FactSnippet No. 507,821

Several Xerox Alto chassis are now on display at the Computer History Museum in Mountain View, California, one is on display at the Computer Museum of America in Roswell, Georgia, and several are in private hands.

FactSnippet No. 507,822

Xerox Alto uses a microcoded design, but unlike many computers, the microcode engine is not hidden from the programmer in a layered design.

FactSnippet No. 507,823

The Xerox Alto has a bit-slice arithmetic logic unit based on the Texas Instruments 74181 chip, a ROM control store with a writable control store extension and has 128 (expandable to 512) KB of main memory organized in 16-bit words.

FactSnippet No. 507,824

Apart from an Ethernet connection, the Xerox Alto's only common output device is a bi-level cathode-ray tube (CRT) display with a tilt-and-swivel base, mounted in portrait orientation rather than the more common "landscape" orientation.

FactSnippet No. 507,825

Early software for the Xerox Alto was written in the programming language BCPL, and later in Mesa, which was not widely used outside PARC but influenced several later languages, such as Modula.

FactSnippet No. 507,826

Xerox Alto helped popularize the use of raster graphics model for all output, including text and graphics.

FactSnippet No. 507,827

Technically, the Xerox Alto was a small minicomputer, but it could be considered a personal computer in the sense that it was used by one person sitting at a desk, in contrast with the mainframe computers and other minicomputers of the era.

FactSnippet No. 507,828

In 1978 Xerox donated 50 Altos to the Massachusetts Institute of Technology, Stanford University, Carnegie Mellon University, and the University of Rochester.

FactSnippet No. 507,829

Xerox Alto was slow to realize the value of the technology that had been developed at PARC.

FactSnippet No. 507,830

These machines, based on the 'Wildflower' architecture described in a paper by Butler Lampson, incorporated most of the Xerox Alto innovations, including the graphical user interface with icons, windows, folders, Ethernet-based local networking, and network-based laser printer services.

FactSnippet No. 507,831

Xerox Alto only realized their mistake in the early 1980s, after Apple's Macintosh revolutionized the PC market via its bitmap display and the mouse-centered interface.

FactSnippet No. 507,832