Evolution of Microprocessor
The history of the microprocessor begins with the birth of the Intel 4004, the first commercially available microprocessor. The roots of this development can be traced directly back to the inventors of the transistor. In 1955, William Shockley founded Shockley Semiconductor in Palo Alto, California (arguably the birth of Silicon Valley). This company eventually employed Gordon Moore and Robert Noyce, who left with others to form Fairchild Semiconductor in 1957. While at Fairchild, Noyce played a significant role in the development of he IC, first commercially available in 1961. In 1968, Moore and Noyce left Fairchild to form Intel Corporation. Intel’s focus at that time was the development of memory chips, but Intel’s history was forever changed by the events leading to the development of the 4004 for the Busicom calculator company. The first fully functional 4004 parts were available in March 1971, with the first public announcement in November 1971. Around the same time Intel developers began working on the 4004, they also began work on the 1201 project for Computer Terminal Corporation (CTC). The 1201 was intended to be a single metal-oxide semiconductor (MOS) chip that would replace a similar processor designed using medium-scale-integration components. The 1201 was later renamed the Intel 8008. The 8008 was the first 8-bit microprocessor and laid the foundation for future microprocessor from Intel. The 8008 was designed in 10-micron PMOS (metal-oxide semiconductor using p-type transistors) technology, and required approximately 3,500 transistors. The die for the 8008 measured 4.9mm, 3.67mm. The 8008 was packaged in an 18-pin dual inline package, ran at 200 kHz, and was capable of 60,000 instructions per second. While the 8008 was being developed, a June 1971 Texas instruments (TI) advertisement in Electronics magazine showing a “Computer On A Chip” revealed that CTC had also contracted with TI to produce a chip similar to the 8008. This presented a difficult