Altair refers to the Altair 8800, a microcomputer designed in 1974 by MITS. It is widely recognized as the spark that ignited the personal computer revolution. Built around the Intel 8080 CPU, it was sold primarily as a mail-order kit for hobbyists, transforming computing from an institutional utility into an accessible individual pursuit.
Sparked the personal computer industry in 1975.
Utilized the Intel 8080 8-bit microprocessor.
Launched the microcomputer hobbyist movement and the Homebrew Computer Club.
Catalyzed the creation of Microsoft through Altair BASIC.
Used the S-100 bus, which became an early industry standard.
The Altair 8800 was developed by Ed Roberts and his company, Micro Instrumentation and Telemetry Systems (MITS), in Albuquerque, New Mexico. Facing bankruptcy, Roberts designed the computer around Intel's new 8080 processor.
Featured on the January 1975 cover of Popular Electronics, the kit saw unprecedented demand, selling thousands of units in its first month instead of the anticipated few hundred. This massive reception proved a viable market for personal computers existed, prompting competitors like IMSAI to enter the space.
The original Altair 8800 lacked a keyboard, monitor, or operating system. Programming it required a manual, multi-step process:
Inputting Code: Users flipped a row of mechanical toggle switches on the front panel to represent binary code (1s and 0s).
Storing to Memory: A deposit switch loaded that specific byte into the machine's random-access memory.
Execution: The process was repeated for every single instruction line.
Reading Output: The computer executed the program and displayed results via flashing LED lights on the front panel, which users decoded from binary back into alphanumeric characters.
The foundational hardware configuration of the base Altair 8800 model included these standard components:
Processor: Intel 8080 8-bit CPU operating at a clock speed of 2 MHz.
Memory: Base model included 256 bytes of RAM, expandable up to 64 KB.
Bus Architecture: S-100 bus system with 100-pin expansion slots.
Storage Options: Paper tape readers, cassette tape interfaces, and later 8-inch floppy disk drives.
I/O Interface: Front panel toggle switches and LED indicator lights.
The architecture of the Altair introduced the S-100 bus, a backplane design featuring 100-pin expansion slots. Because the base machine lacked standard input and output hardware, users needed expansion cards to add capabilities. The S-100 bus allowed third-party manufacturers to build functional add-ons, such as:
Additional memory boards to expand past 256 bytes.
Video display interfaces to connect standard monitors.
Serial and parallel I/O cards for teletype machines and keyboards.
Disk controller cards to run early floppy disk drives.
The Altair 8800 directly influenced the birth of the consumer software industry. Recognizing the limitations of binary switch programming, Paul Allen and Bill Gates wrote a version of the BASIC programming language interpreter for the Intel 8080 chip.
After successfully demonstrating it to Ed Roberts, MITS agreed to distribute the software as Altair BASIC. This success prompted Gates and Allen to formally establish "Micro-Soft" (later changing the name to Microsoft), marking the transition from hardware-dominated computing to a specialized software industry.
Affordable price point for individual electronics hobbyists.
Modular design allowed custom component expansion.
Established the first universal open bus standard for microcomputers.
Provided a practical hardware platform for learning assembly and binary coding.
Extremely difficult for non-technical users to program or operate.
Base model lacked sufficient memory to run high-level software languages.
No native video output or alphanumeric keyboard support out of the box.
Assembly required soldering skills, often leading to build defects.
The Altair 8800 shifted the public perception of computers from massive, corporate mainframes to personal tools. It served as the central catalyst for the Homebrew Computer Club in Silicon Valley, where members like Steve Wozniak and Steve Jobs examined the Altair before designing their own machines. Without the market validation provided by the Altair, the development of early personal computers like the Apple I and Apple II would have faced a significantly harder path to commercial viability.
Intel 8080: The 8-bit microprocessor that powered the Altair 8800.
S-100 Bus: The open expansion architecture popularized by the Altair system.
Microcomputer: An early term for a computer built around a single-chip microprocessor.
MITS: Micro Instrumentation and Telemetry Systems, the creator company of the Altair.
Altair BASIC: The first programming language interpreter developed by Microsoft.
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