Altair 8800

MITS Altair 8800

Basic Info

The Altair 8800 is considered the very first personal computer in the history of computer science: it was easy affordable and obtainable. Before the Altair 8800 the word "computer" was related to big calculators, very expensive and not purchasable for individual usage. It was featured in 1975 by the MITS (Micro Instrumentation & Telemetry Systems) in the magazine Popular Electronics and its inventor, Edward Roberts, created it with the hope that "one day I will give a computer to every person".
The innovation fo Altair 8800 was that, with a supplement of 100$, you could buy the computer ready-assembled. You could also buy it unassembled and you had to assemble it by yourself and you could add some extras like an expanded memory, a teletype terminal or an Audio Cassette interface board.

Components

When the Altair did its first appearance, it was composed by a metal box and inside a power source, a front panel and a motherboard, made of slots, that was connected with the CPU and the main memory (placed on separated slots) through a bus called S-100 bus (Altair bus). Inside the ROM was inserted an Altair BASIC programming language ( a simplified version of the standard BASIC).The CPU was the Intel 8080 microprocessor and it had a RAM of 256 Bytes expandable to 64 kB. The front panel was made of a big number of switches and LEDs. The only thing that you could do was make programs in binary with the switches and see the result with the LEDs. For example you could put on some switches to make blink some LEDs.

The following years, Mr Roberts did some powerful implementations, creating additional cards to increase the RAM, for the keyboard interface or for paper tapes for data storage. He also worked on the RS-232 to connect the interface to a terminal.

Altair VI in Star Trek

Curiosity

There are some urban legends about the choice of the name. It's said that Edward Roberts asked his daughter to choose the name and she chose Altair because the night before she was watching an episode of Star Trek where there was a system called indeed Altair. A more accredited version tells that the name was chose during a meeting of MITS.
Bill Gates worked personally on the software inside Altair and, after the success, he decided to build Microsoft.