Microprocessors

The Intel 8080 8-bit microprocessor was introduced publicly in April, 1974, and was an extended and enhanced variant of the earlier 8008 design. The chip had a retail price tag of “just” $360 at introduction, which soon was reduced to $3-5 in quantity. The 40 pin chip contains 6,000 transistors and runs at 2 MHz.

Intel 8080A microarchitecture – Wikimedia Commons

The 8080 needs at least two support chips to function in most applications, the i8224 clock generator/driver and the i8228 bus controller. A family of support chips were also available:

Intel 8080A System Development Kit block diagram from the Intel MCS80/SDK-80 Development Kit

 

Altair 8800 – the first “Personal Computer”

The first “personal computer”, a full microcomputer kit using the Intel 8080 was announced in January 1975 – the Altair 8800, for $375.00. That was barely more than the retail single unit cost of an 8080 chip. It included 256 bytes of 8 bit memory! Input/output was 16 toggle switches and 16 LED lights on the front panel. You could add memory or other I/O cards (like a serial card for connecting to a Teletype ASR 33 terminal) for added cost. The most expensive component of  any  computer at that time was memory. Now anyone could build their own computer!

January 1975 Popular Electronics Magazine introducing the Altair 8800 “Minicomputer” Kit

 

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