The Xerox Alto is a computer system developed at Xerox PARC (Palo Alto Research Center) in the 1970s. It is considered one of the first workstations or personal computers, and its development pioneered many aspects of modern computing. It features a graphical user interface (GUI), a mouse, Ethernet networking, and the ability to run multiple applications simultaneously. It is one of the first computers to use a WYSIWYG (What You See Is What You Get) text editor and has a bit-mapped display. The Alto did not succeed commercially, but it had a significant influence on the development of future computer systems.
The Alto was designed for an operating system based on a GUI, later using the desktop metaphor.[6][7] The first machines were introduced on March 1, 1973,[8] and in limited production starting one decade before Xerox's designs inspired Apple to release the first mass-market GUI computers. The Alto is contained in a relatively small cabinet and uses a custom central processing unit (CPU) built from multiple SSI and MSIintegrated circuits. Each machine cost tens of thousands of dollars. Few were built initially, but by the late 1970s, about 1,000 were in use at various Xerox laboratories, and about another 500 in several universities. Total production was about 2,000 systems.
The Alto became well known in Silicon Valley and its GUI was increasingly seen as the future of computing. In 1979, Steve Jobs arranged a visit to Xerox PARC, during which Apple Computer personnel received demonstrations of Xerox technology in exchange for Xerox being able to purchase stock options in Apple.[9] After two visits to see the Alto, Apple engineers used the concepts in developing the Lisa and Macintosh systems.
In 1981, Xerox commercialized a line of office computers, the Star, based on concepts from the Alto. A complete office system including several workstations, storage, and a laser printer cost up to $100,000(equivalent to $335,000 in 2023). Like the Alto, the Star had little direct impact on the market.
History
Alto mouse
The top three buttons.
The underside has three rolling balls.
The Alto keyset is a chorded keyboard that never became popular.
The Alto is the first computer with a graphical operating system, and was built on earlier graphical interface designs. It was conceived in 1972 in a memo written by Butler Lampson, inspired by the oN-Line System (NLS) developed by Douglas Engelbart and Dustin Lindberg at SRI International (SRI). Of further influence was the PLATO education system developed at the Computer-based Education Research Laboratory at the University of Illinois.[10] The Alto was designed mostly by Charles P. Thacker. Industrial Design and manufacturing was sub-contracted to Xerox, whose Special Programs Group team included Doug Stewart as Program Manager, Abbey Silverstone Operations Manager, Bob Nishimura, Industrial Designer. An initial run of 30 units was produced by Xerox El Segundo (Special Programs Group), working with John Ellenby at PARC and Doug Stewart and Abbey Silverstone at El Segundo, who were responsible for re-designing the Alto's electronics. Due to the success of the pilot run, the team went on to produce approximately 2,000 units over the next ten years.[11]
On October 21, 2014, Xerox Alto's source code and other resources were released from the Computer History Museum.[14]
Architecture
The following description is based mostly on the August 1976 Alto Hardware Manual by Xerox PARC.[15]
Alto uses a microcoded design, but unlike many computers, the microcode engine is not hidden from the programmer in a layered design. Applications such as Pinball take advantage of this to accelerate performance. The Alto has a bit-slicearithmetic logic unit (ALU) based on the Texas Instruments74181 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. Mass storage is provided by a hard disk drive that uses a removable 2.5 MB one-platter cartridge (Diablo Systems, a company Xerox later bought) similar to those used by the IBM 2310. The base machine and one disk drive are housed in a cabinet about the size of a small refrigerator; one more disk drive can be added via daisy-chaining.
Alto both blurs and ignores the distinction between functional elements. Rather than a distinct central processing unit with a well-defined electrical interface (such as a system bus) to storage and peripherals, the Alto ALU interacts directly with hardware interfaces to memory and peripherals, driven by microinstructions that are output from the control store. The microcode machine supports up to 16 cooperative multitasking tasks, each with fixed priority. The emulator task executes the normal instruction set to which most applications are written; that instruction set is similar to a Data General Nova.[16] Other tasks serve the display, memory refresh, disk, network, and other I/O functions. For example, the bitmap display controller is little more than a 16-bitshift register; microcode moves display refresh data from main memory to the shift register, which serializes it into a display of pixels corresponding to the ones and zeros of the memory data. Ethernet is likewise supported by minimal hardware, with a shift register that acts bidirectionally to serialize output words and deserialize input words. Its speed was designed to be 3Mbit/s because the microcode engine can not go faster and continue to support the video display, disk activity, and memory refresh.
Unlike most minicomputers of the era, Alto does not support a serial terminal for user interface. Apart from an Ethernet connection, the Alto's only common output device is a bi-level (black and white) cathode-ray tube (CRT) display with a tilt-and-swivel base, mounted in portrait orientation rather than the more common "landscape" orientation. Its input devices are a custom detachable keyboard, a three-button mouse, and an optional 5-key chorded keyboard (chord keyset). The last two items had been introduced by SRI's On-Line System and the mouse was an instant success among Alto users, but the chord keyset never became popular.
In the early mice, the buttons are three narrow bars, arranged top to bottom rather than side to side; they were named after their colors in the documentation. The motion is sensed by two perpendicular wheels. These were soon replaced with a ball-type mouse, which was invented by Ronald E. Rider and developed by Bill English. These are photo-mechanical mice, first using white light, and then infrared (IR), to count the rotations of wheels inside the mouse.
Each key on the Alto keyboard is represented as a separate bit in a set of memory locations. As a result, it is possible to read multiple key presses concurrently. This trait can be used to alter from where on the disk the Alto boots. The keyboard value is used as the sector address on the disk to boot from, and by holding specific keys down while pressing the boot button, different microcode and operating systems can be loaded. This gave rise to the expression "nose boot" where the keys needed to boot for a test OS release requires more fingers than the user can articulate. Nose boots were obsoleted by the move2keys program that shifts files on the disk so that a specified key sequence can be used.
Several other I/O devices were developed for the Alto, including a television camera, the Hy-Type daisywheel printer and a parallel port, although these were quite rare. The Alto could also control external disk drives to act as a file server. This was a common application for the machine.
Software
Neptune is the Alto's file manager program.
Early software for the Alto was written in the programming languageBCPL, and later in Mesa,[1] which was not widely used outside PARC but influenced several later languages, such as Modula. The Alto used an early version of ASCII which lacked the underscore character, instead having the left-arrow character used in ALGOL 60 and many derivatives for the assignment operator: this peculiarity may have been the source of the CamelCase style for compound identifiers. Altos were also microcode-programmable by users.[15]
The Alto helped popularize the use of raster graphics model for all output, including text and graphics. It also introduced the concept of the bit block transfer operation (bit blit, BitBLT), as the fundamental programming interface to the display. Despite its small memory size, many innovative programs were written for the Alto, including:
There was no spreadsheet or database software. The first electronic spreadsheet program, VisiCalc, did not appear until 1979.
Diffusion and evolution
Technically, the Alto is a small minicomputer, but it could be considered a personal computer in the sense that it is used by one person sitting at a desk, in contrast with the mainframe computers and other minicomputers of the era. It is arguably "the first personal computer", although this title is disputed. More significantly (and perhaps less controversially), it may be considered to be one of the first workstation systems, with successors such as the Apollo workstations and systems by Symbolics (designed to natively run Lisp as a development environment).[20]
In 1976 to 1977, the Swiss computer pioneer Niklaus Wirth spent a sabbatical at PARC and was excited by the Alto. Unable to bring back an Alto system to Europe, Wirth decided to build a new system from scratch and he designed with his group the Lilith.[21] It was ready to use around 1980, before Apple released Lisa in 1981 and Macintosh in 1984. Around 1985, Wirth started a complete redesign of the Lilith under the Name "Project Oberon".
Following the acquisition of an Alto, the White House information systems department sought to lead federal computer suppliers in its direction. The Executive Office of the President of the United States (EOP) issued a request for proposal for a computer system to replace the aging Office of Management and Budget (OMB) budget system, using Alto-like workstations, connected to an IBM-compatible mainframe. The request was eventually withdrawn because no mainframe producer could supply such a configuration.
In December 1979, Apple Computer's co-founder Steve Jobs visited Xerox PARC, where he was shown the Smalltalk-76 object-oriented programming environment, networking, and most importantly the WYSIWYG, mouse-driven graphical user interface provided by the Alto. At the time, he didn't recognize the significance of the first two, but was excited by the last one. The GUI was promptly integrating into Apple's products, first into the Lisa and then in the Macintosh, and Jobs recruited several key researchers from PARC.[23]
In 1980-1981, Altos were used by engineers at PARC and at the Xerox System Development Department to design the Star workstations.
Xerox and the Alto
Xerox was slow to realize the value of the technology that had been developed at PARC.[24] The Xerox corporate acquisition of Scientific Data Systems (SDS, later XDS) in the late 1960s had no interest to PARC. PARC built their own emulation of the Digital Equipment Corporation PDP-10 named the MAXC.[25] The MAXC was PARC's gateway machine to the ARPANET. The firm was reluctant to get into the computer business again with commercially untested designs, although many of the philosophies would ship in later products.
It is unlikely that a person outside of the computer-science research community will ever be able to buy an Alto. They are not intended for commercial sale, but rather as development tools for Xerox, and so will not be mass-produced. What makes them worthy of mention is the fact that a large number of the personal computers of tomorrow will be designed with knowledge gained from the development of the Alto.
After the Alto, PARC developed more powerful workstations (none intended as projects[clarification needed]) informally termed "the D-machines": Dandelion (least powerful, but the only to be made a product in one form), Dolphin; Dorado (most powerful; an emitter-coupled logic (ECL) machine); and hybrids like the Dandel-Iris.
Before the advent of personal computers such as the Apple II in 1977 and the IBM Personal Computer (IBM PC) in 1981, the computer market was dominated by costly mainframes and minicomputers equipped with dumb terminals that time-shared the processing time of the central computer. Through the 1970s, Xerox showed no interest in PARC's work. When Xerox finally entered the PC market with the Xerox 820, it pointedly rejected the Alto design and opted instead for a very conventional model, a CP/M-based machine with the then-standard 80 by 24 character-only monitor and no mouse.
With the help of PARC researchers, Xerox eventually developed the Star, based on the Dandelion workstation, and later the cost-reduced Star, the 6085 office system, based on the Daybreak workstation. These machines, based on the Wildflower architecture described in a paper by Butler Lampson, incorporated most of the Alto innovations, including the graphical user interface with icons, windows, folders, Ethernet-based local networking, and network-based laser printer services.
Xerox only realized its mistake in the early 1980s, after the Macintosh revolutionized the PC market via its bitmap display and the mouse-centered interface. Both of these were inspired by the Alto.[24] The Xerox Star series was a relative commercial success, but it came too late. The expensive Xerox workstations could not compete against the cheaper GUI-based workstations that arose in the wake of the first Macintosh, and Xerox eventually quit the workstation market.
A graphical user interface, or GUI, is a form of user interface that allows users to interact with electronic devices through graphical icons and visual indicators such as secondary notation. In many applications, GUIs are used instead of text-based UIs, which are based on typed command labels or text navigation. GUIs were introduced in reaction to the perceived steep learning curve of command-line interfaces (CLIs), which require commands to be typed on a computer keyboard.
The history of the graphical user interface, understood as the use of graphic icons and a pointing device to control a computer, covers a five-decade span of incremental refinements, built on some constant core principles. Several vendors have created their own windowing systems based on independent code, but with basic elements in common that define the WIMP "window, icon, menu and pointing device" paradigm.
Mesa is a programming language developed in the mid 1970s at the Xerox Palo Alto Research Center in Palo Alto, California, United States. The language name was a pun based upon the programming language catchphrases of the time, because Mesa is a "high level" programming language.
In computing, WYSIWYG, an acronym for What You See Is What You Get, refers to software which allows content to be edited in a form that resembles its appearance when printed or displayed as a finished product, such as a printed document, web page, or slide presentation. WYSIWYG implies a user interface that allows the user to view something very similar to the result while the document is being created. In general, WYSIWYG implies the ability to directly manipulate the layout of a document without having to type or remember names of layout commands.
SRI Future Concepts Division is a research and development company in Palo Alto, California. It was founded in 1969 by Jacob E. "Jack" Goldman, chief scientist of Xerox Corporation, as a division of Xerox, tasked with creating computer technology-related products and hardware systems.
In the industrial design field of human–computer interaction, a user interface (UI) is the space where interactions between humans and machines occur. The goal of this interaction is to allow effective operation and control of the machine from the human end, while the machine simultaneously feeds back information that aids the operators' decision-making process. Examples of this broad concept of user interfaces include the interactive aspects of computer operating systems, hand tools, heavy machinery operator controls and process controls. The design considerations applicable when creating user interfaces are related to, or involve such disciplines as, ergonomics and psychology.
Lisa is a desktop computer developed by Apple, released on January 19, 1983. It is generally considered the first mass-market personal computer operable through a graphical user interface (GUI). In 1983, a machine like the Lisa was still so expensive that it was primarily marketed to individual and small and medium-sized businesses as a groundbreaking new alternative to much bigger and more expensive mainframes or minicomputers such as from IBM, that either require additional, expensive consultancy from the supplier, hiring specially trained personnel, or at least, a much steeper learning curve to maintain and operate. Earlier GUI-controlled personal computers were not mass-marketed; for example, the Xerox Alto was manufactured only for Xerox and select partners through Xerox PARC from the early to mid-1970s.
Butler W. Lampson FRS is an American computer scientist best known for his contributions to the development and implementation of distributed personal computing.
The Xerox Star workstation, officially named Xerox 8010 Information System, is the first commercial personal computer to incorporate technologies that have since become standard in personal computers, including a bitmapped display, a window-based graphical user interface, icons, folders, mouse (two-button), Ethernet networking, file servers, print servers, and email.
In computing, a window is a graphical control element. It consists of a visual area containing some of the graphical user interface of the program it belongs to and is framed by a window decoration. It usually has a rectangular shape that can overlap with the area of other windows. It displays the output of and may allow input to one or more processes.
In computing, the desktop metaphor is an interface metaphor which is a set of unifying concepts used by graphical user interfaces to help users interact more easily with the computer. The desktop metaphor treats the computer monitor as if it is the top of the user's desk, upon which objects such as documents and folders of documents can be placed. A document can be opened into a window, which represents a paper copy of the document placed on the desktop. Small applications called desk accessories are also available, such as a desk calculator or notepad, etc.
Lawrence Gordon Tesler was an American computer scientist who worked in the field of human–computer interaction. Tesler worked at Xerox PARC, Apple, Amazon, and Yahoo!.
The following outline is provided as an overview of and topical guide to human–computer interaction:
Robert William Taylor, known as Bob Taylor, was an American Internet pioneer, who led teams that made major contributions to the personal computer, and other related technologies. He was director of ARPA's Information Processing Techniques Office from 1965 through 1969, founder and later manager of Xerox PARC's Computer Science Laboratory from 1970 through 1983, and founder and manager of Digital Equipment Corporation's Systems Research Center until 1996.
The PERQ, also referred to as the Three Rivers PERQ or ICL PERQ, is a pioneering workstation computer produced in the late 1970s through the early 1980s. It is the first commercially-produced personal workstation with a graphical user interface (GUI). The design of the PERQ was heavily influenced by the original workstation computer, the Xerox Alto, which was never commercially produced. The workstation was conceived by six former Carnegie Mellon University alumni and employees: Brian S. Rosen, James R. Teter, William H. Broadley, J. Stanley Kriz, Raj Reddy and Paul G. Newbury, who formed the startup Three Rivers Computer Corporation (3RCC) in 1974.
Bravo was the first WYSIWYG document preparation program. It provided multi-font capability using the bitmap displays on the Xerox Alto personal computer. It was produced at Xerox PARC by Butler Lampson, Charles Simonyi and colleagues in 1974.
Daniel Henry Holmes Ingalls Jr. is a pioneer of object-oriented computer programming and the principal architect, designer and implementer of five generations of Smalltalk environments. He designed the bytecoded virtual machine that made Smalltalk practical in 1976. He also invented bit blit, the general-purpose graphical operation that underlies most bitmap computer graphics systems today, and pop-up menus. He designed the generalizations of BitBlt to arbitrary color depth, with built-in scaling, rotation, and anti-aliasing. He made major contributions to the Squeak version of Smalltalk, including the original concept of a Smalltalk written in itself and made portable and efficient by a Smalltalk-to-C translator.
Gypsy was the first document preparation system based on a mouse and graphical user interface to take advantage of those technologies to virtually eliminate modes. Its operation would be familiar to any user of a modern personal computer. It was the second WYSIWYG document preparation program, a successor to the Bravo on the Xerox Alto personal computer.
Charles Patrick "Chuck" Thacker was an American pioneer computer designer. He designed the Xerox Alto, which is the first computer that used a mouse-driven graphical user interface (GUI).
Metaphor Computer Systems (1982–1994) was an American computer company that created an advanced workstation, database gateway, unique graphical office interface, and software applications that "seamlessly integrate" data from both internal and external sources. The Metaphor machine was one of the first commercial workstations to offer a complete hardware/software package and a GUI, including "a wireless mouse and a wireless five-function key pad". Although the company achieved some commercial success, it never achieved the fame of either the Apple Macintosh or Microsoft Windows.
↑ Dear, Brian (2017). The Friendly Orange Glow: The untold story of the PLATO System and the dawn of cyberculture. Pantheon Books. pp.186–187. ISBN978-1-101-87155-3.
↑ "The History of the Xerox Alto". Carl J. Clement. March 2002.
↑ McJones, Paul (October 21, 2014). "Xerox Alto Source Code - The roots of the modern personal computer". Software Gems: The Computer History Museum Historical Source Code Series. Computer History Museum. Archived from the original on January 2, 2015. Retrieved January 8, 2015. With the permission of the Palo Alto Research Center, the Computer History Museum is pleased to make available, for non-commercial use only, snapshots of Alto source code, executables, documentation, font files, and other files from 1975 to 1987.
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