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Xerox Alto: The Groundbreaking Computer Behind the GUI Revolution

The Xerox Alto was one of the first computers to feature a graphical user interface (GUI) with windows, icons and menus. Developed in 1973 at Xerox PARC, the Alto pioneered concepts like WYSIWYG editing, Ethernet networking and laser printing. Though ahead of its time, the Alto inspired breakthrough products from Apple and Microsoft that popularized graphical computing as we know it.

Let‘s take a deeper look at this influential system and how it fundamentally changed the direction of personal computing.


The Xerox Alto was developed by an all-star team at Xerox PARC including Butler Lampson, Chuck Thacker, Alan Kay and others. Though not commercially successful itself, the Alto was the first complete realization of a personal computer with:

  • An easy-to-use GUI with windows, menus and icons
  • Powerful WYSIWYG text and graphics editors
  • Local area networking using Ethernet
  • A mouse for point and click interaction
  • Interchangeable data storage via removable disk packs

These innovative features made computing more accessible to everyday users. The Alto‘s GUI approach directly inspired the Apple Lisa, Macintosh, and Microsoft Windows, cementing graphical interfaces and WYSIWYG editing as key elements of the personal computing experience.

So while you may never have used an Alto, its DNA is found in every GUI-based system you use today! Let‘s look closer at what made this pioneering machine so special.

Revolutionary Hardware

For 1973, the Alto‘s hardware capabilities were remarkable:

  • 128KB RAM – Extremely spacious for the time. Increased to 512KB in later models.
  • 2.5MB removable hard disk – Earlier systems used far smaller floppy disks.
  • 5.8 MHz CPU – Optimized for screen editing vs raw compute.
  • 606×808 pixel display – Unusually high resolution in portrait orientation.
  • Ethernet networking – The Alto pioneered local area networking.
  • Mouse and keyboard – Intuitive input devices.

To put this in perspective, here is how the original Alto compared to other 1973-era systems:

Specification Xerox Alto Xerox Sigma 9 IBM System/3
Year introduced 1973 1971 1969
RAM 128KB 512KB 8KB
Disk storage 2.5MB 2.5MB 200KB
Display 606×808 512×512 None
Mouse input Yes No No
Networking Ethernet None None

As you can see, the Alto was far ahead of conventional computers in adopting a bitmap display, local networking, removable mass storage and mouse input. These innovations were perfectly suited to run the Alto‘s pioneering graphical software.

Software Revolution

The Alto operating system featured revolutionary graphical software developed at PARC including:

  • Overlapping, resizable windows – A complete paradigm shift from line interfaces.
  • WYSIWYG text editing – What you saw on screen mirrored printed output.
  • Icons – Represented files, apps and devices visually.
  • Menus – Executed commands without memorizing syntax.
  • Object-oriented programming – Smalltalk paved the way for OOP languages.

This graphical environment enabled real-time editing of text, drawings, code and more. The approachable interface allowed less technical users to adopt computers for knowledge work.

Notable Alto applications included:

  • Bravo – The first WYSIWYG document editor with font support.
  • Gypsy – An advanced WYSIWYG word processor.
  • Draw – An intuitive freeform graphics editor.
  • Markup – A bitmap graphics editor.
  • Sil – An innovative VLSI circuit design tool.

User Larry Tesler described the exhilarating experience:

"Using the Alto for the first time was exciting! We could easily visualize ideas, experiment, and iterate designs."

By radically advancing both its hardware and software, the Alto brought the GUI paradigm to complete fruition and proven effectiveness.

Inspiring the Future

Although not commercially successful itself, the Alto inspired GUI-based systems that forever changed personal computing:

  • Apple Lisa and Macintosh – After visiting PARC in 1979, Steve Jobs remarked "They showed me the future." The Lisa and Mac borrowed many interface concepts directly from the Alto.
  • Microsoft Windows – Windows 1.0 adopted the WYSIWYG, windowed GUI model for mainstream PCs, establishing Microsoft‘s dominance.

PARC researcher Dr. Adele Goldberg discussed the Alto‘s industry impact:

"The Alto interface designed at PARC pioneered concepts like windows, menus and WYSIWYG that are still central to computing today."

In addition to the GUI, the Alto‘s technical innovations like Ethernet, laser printing and object-oriented programming became industry standards. Although you may never have seen an Alto, its DNA is deeply embedded in every personal computer used today. This pioneering machine ushered in the era of interactive graphical computing.

I hope you‘ve enjoyed learning more about the remarkable Xerox Alto! Let me know if you have any other questions.