Altair 8800

Released in January 1975 by MITS (Micro Instrumentation and Telemetry Systems), the Altair 8800 is often credited as the first commercially successful personal computer. It wasn’t the first programmable microcomputer, but it was the one that sparked widespread interest among hobbyists and tinkerers - including a couple of guys named Bill Gates and Paul Allen.

Tech Specs

• CPU: Intel 8080 @ 2MHz
• RAM: 256 bytes base (expandable to 64 KB)
• Storage: None built-in (originally required punched tape or later cassette/drive options)
• Input/Output: Toggle switches and LEDs on the front panel
• Bus: S-100 bus (which became a de facto standard)

What You Got

When you ordered one, you didn’t get a nice box with a monitor and keyboard - you got a kit. A literal bag of parts and a metal case. Assembly was required. Many early buyers were radio hobbyists who had the tools and the know-how to put it together.

Programming the Altair

Programming was done by flipping switches on the front panel to enter binary opcodes, then watching LEDs for output. Later, users could add:

• Teletype terminals (ASR-33s were popular)
• Cassette tape interfaces
• Memory expansion boards
• And crucially… Altair BASIC - a version of BASIC written by Gates and Allen under the newly formed Microsoft.

Impact

• Featured on the cover of the January 1975 issue of Popular Electronics.
• Inspired the formation of the Homebrew Computer Club, where hobbyists like Steve Wozniak and Steve Jobs got their start.
• Altair BASIC was Microsoft’s first product.

Legacy

• The Altair 8800 paved the way for machines like the Apple I and II, the TRS-80, and the Commodore PET.
• It introduced the concept of a personal computer to the mainstream.
• Its S-100 bus architecture influenced many future computers.

Timeline

• January 1975: The Popular Electronics cover story hits newsstands.
• Early January 1975: MITS began taking orders immediately after the magazine was published.
• March 1975: The first kits started shipping to customers - notably slower than the demand, which overwhelmed MITS.
• 1977: MITS was acquired by Pertec Computer Corporation, who were more interested in the commercial minicomputer market.
• 1978: Pertec discontinued the Altair line, shifting focus away from hobbyist microcomputers.