The first of the programmable pocket calculators was Hewlett-Packard’s HP-65, introduced in early 1974 for $795.
Texas Instruments and other followed. As powerful as they were, the trade press was hesitant to called computers, even if Hewlett-Packard introduced the HP-65 as a ‘personal computer’ (possibly the first use of that term in print).
In April 1974, Intel introduced the 8080 microprocessor, which was 10 times faster than the earlier 8008 chip and addressed 64 KB of memory.
In July 1974, Radio –Electronics described the Mark-8 and featured Johnathan Titus, who developed early personal computer which though not commercially produced.
In late December 1974, subscribers to Popular Electronics received their January 1975 issue in the mail, with the prototype of the ‘Altair’ minicomputer on the cover, and article describing how readers could obtain Altair kit for less than $400 and had to be assembled. The Altair kit, considered the first personal computer, included an 8080 processor, a power supply, a front panel with a large number of lights and 256 bytes of memory.
The designers hoped to sell a few hundred build-it-yourself kits to hobbyist and were surprised when they sold thousands in the first month.
H. Edward Roberts, the Altair’s designer, served as credit as the inventor of the personal computer. The Altair was a capable, inexpensive computer designed around the Intl 8080 microprocessor.
IBM introduced their first personal computer in September 1975, six years before the IBM PC. The model 5100 had 16 KB of memory, a built in 16 line-by-64-character display, a built in BASIC language interpreter and a built-in DC-300 cartridge tape drive for storage.
In 1977, Apple Computer Corporation founded by Steve Jobs and Steve Wozniak, released Apple I containing a system board with 4 KB of RAM. It sold for $666.66.
Invention history of personal computer