The Altair 8800 launched the desktop computer era in 1975

The Altair 8800, released in January 1975, is widely recognized as the first desktop computer. It was built by Micro Instrumentation and Telemetry Systems (MITS) in Albuquerque, New Mexico, and cost $397 for the basic kit—roughly $2,300 when adjusted for inflation. The machine used an Intel 8080 processor, had 256 bytes of memory in its base configuration, and came as a kit you had to assemble yourself. It had no keyboard, no monitor, and no disk drive. Instead, you entered programs using toggle switches on the front panel and read results from a row of blinking lights.

The Altair became the first computer that individual hobbyists could actually own and tinker with. Before it, computers were room-sized machines that belonged to universities, corporations, and government agencies. The Altair's arrival in Popular Electronics magazine sparked a wave of interest among electronics enthusiasts and led directly to the founding of the Apple Computer Company and Microsoft, both of which started by writing software for the Altair.

Key Takeaways

  • The Altair 8800, released in January 1975, is considered the first desktop computer and cost around $397 as a kit.
  • It had no keyboard, monitor, or disk drive—you programmed it using toggle switches and read output from blinking lights.
  • The Altair used an Intel 8080 processor and came with 256 bytes of memory, which is millions of times smaller than modern computers.
  • The Altair's success created a market for personal computers and directly led to the founding of Apple and Microsoft.
  • Earlier computers existed but were room-sized machines owned by institutions, not individuals.

What made the Altair different from earlier computers

Before 1975, computers were expensive, massive machines. The ENIAC, built in 1946, weighed 30 tons and filled an entire room. The IBM System/360, introduced in 1964, was a commercial mainframe that cost hundreds of thousands of dollars. These machines required specialized operators, climate-controlled rooms, and dedicated power supplies. Only large organizations could afford them.

The Altair changed this equation by being small enough to fit on a desk, affordable enough for individuals to buy, and straightforward enough that hobbyists could understand how it worked. It was not the first small computer—the Intel 4004, released in 1971, was smaller—but the 4004 was designed for calculators and embedded systems, not as a general-purpose machine you could program and use yourself. The Altair was the first to combine affordability, size, and programmability in a way that appealed to the general public.

How the Altair 8800 actually worked

The Altair 8800 was a metal box about the size of a small suitcase with a front panel covered in toggle switches and lights. To run a program, you flipped switches in a specific sequence to enter binary code directly into memory. Each switch represented a 1 or 0. Once you had entered your program, you pressed a button to execute it, and the results appeared as patterns of blinking lights on the panel—you had to interpret the light patterns to understand what the computer had calculated.

The machine had 256 bytes of base memory, expandable to 64 kilobytes with additional boards. A kilobyte is 1,024 bytes. To put this in perspective, a single photograph from a modern smartphone is typically several megabytes—millions of bytes. The Altair could store perhaps a few dozen lines of straightforward code or a small list of numbers. It had no operating system in the modern sense. You were essentially talking directly to the processor through the switches.

Despite these limitations, people used the Altair to write games, perform calculations, and learn how computers actually worked at the hardware level. The hands-on nature of programming the Altair—physically flipping switches and watching lights respond—gave users a direct understanding of binary logic and machine instruction that is harder to grasp when you type commands into a keyboard.

The role of software in making the Altair useful

The Altair became truly useful when software became available for it. In 1975, two young programmers named Bill Gates and Paul Allen wrote a version of the BASIC programming language for the Altair. BASIC was much easier to use than entering binary code by hand. Instead of flipping switches, you could type commands in English-like syntax. This software became the foundation of Microsoft.

Around the same time, Steve Jobs and Steve Wozniak were inspired by the Altair to build their own computer. They founded Apple Computer Company in 1976 and released the Apple I, which had a keyboard and could connect to a monitor or television. The Apple II, released in 1977, came with a color monitor, a disk drive, and a version of BASIC already built in. These machines were easier to use than the Altair, but the Altair proved that a market for personal computers existed.

Why the Altair is considered the first desktop computer

The Altair holds the title of first desktop computer because it was the first machine that met three criteria at once: it was small enough to fit on a desk, it was affordable enough for individuals to purchase, and it was a general-purpose computer that could run different programs. Earlier computers were either too large, too expensive, or designed for a single specific task.

Some historians point to earlier machines like the IBM 5100, released in 1975 around the same time as the Altair, as contenders for the title. The IBM 5100 was more polished and easier to use, but it cost $9,000 to $20,000—far more than the Altair. The Altair's lower price and hobbyist appeal made it the machine that actually created the personal computer market, even though it was harder to use.

How desktop computers evolved after 1975

The years when ready after the Altair saw rapid change. The Apple II (1977) introduced the concept of a computer that came fully assembled, with a keyboard and monitor, and software already installed. The Commodore 64 (1982) became the best-selling computer of its era by offering color graphics and sound at a low price. The IBM PC (1981) established the standard that most computers still follow today—an open architecture where different manufacturers could build compatible components.

By the mid-1980s, desktop computers had graphical user interfaces (the Macintosh in 1984), hard disk drives instead of floppy disks, and enough memory to run complex programs. The machines became faster, cheaper, and more capable every few years. The trajectory from the Altair's 256 bytes of memory and toggle-switch interface to a modern computer with gigabytes of memory and a touchscreen happened in less than 50 years.

Frequently Asked Questions

Was the Altair 8800 really the first desktop computer ever made?

The Altair is the most widely recognized first desktop computer because it was the first affordable, general-purpose machine small enough to fit on a desk. Earlier computers existed but were either room-sized, extremely expensive, or designed for specific tasks. The IBM 5100 came out around the same time but cost far more.

Could you actually do useful work on an Altair 8800?

Yes, but with significant limitations. Once BASIC programming language became available, users could write straightforward programs for calculations, games, and data storage. However, the tiny memory and lack of a keyboard or monitor meant you could not run the kinds of programs modern computers handle. It was useful for learning and hobbyist projects, not for business or professional work.

How much did an Altair 8800 cost compared to computers today?

The base kit cost $397 in 1975, which is roughly $2,300 when adjusted for inflation. A modern desktop computer costs between $500 and $2,000 depending on the model, so the Altair was expensive for what it could do. However, it was revolutionary because it was the first time an individual could own a computer at all.

Why did the Altair disappear if it was so important?

The Altair was quickly surpassed by easier-to-use machines like the Apple II and Commodore 64. These computers came fully assembled with keyboards, monitors, and built-in software. The Altair required assembly and programming knowledge that most people did not have. Its importance was historical—it proved the market existed—not practical for long-term use.

Did the Altair have an operating system?

No. The Altair ran programs directly on the processor without an operating system in the modern sense. You entered code using toggle switches or typed BASIC commands into memory. Operating systems like CP/M and later DOS came later and made computers much easier to use by managing files, memory, and programs automatically.