The 4004 processor

With the recent launch of the iPhone 5S with its 64 bit A7 processor it is good to remember that the chip race all started with the 4 bits 4004 in 1971.

The Intel 4004 is a 4-bit central processing unit (CPU) released by Intel Corporation in 1971.
It was the first commercially available microprocessor. The first public mention of 4004 was an advertisement in the November 15, 1971 edition of Electronic News.
Packaged in a 16-pin ceramic dual in-line package, the 4004 was the first commercially available computer processor designed and manufactured by chip maker Intel,  which had previously made semiconductor memory chips. 

The chief designers of the chip were Federico Faggin and Ted Hoff of Intel, and Masatoshi Shima of Busicom. The 4004 employed a 10 µm process silicon-gate enhancement load pMOS technology and could execute approximately 92,000 instructions per second; 
a single instruction cycle was 10.8 microseconds. The original clock speed design goal was 1 MHz however 740 kHz was the max clock speed realized.

The Intel 4004 was designed by physically cutting sheets of Rubylith into thin strips to lay out the circuits to be printed,  a process made obsolete by current computer graphic design capabilities

Some tech data:
Semiconductors: 2300 transistors
Maximum clock speed was 740 kHz
Instruction cycle time: 10.8 µs(8 clock cycles / instruction cycle)
Instruction execution time 1 or 2 instruction cycles (10.8 or 21.6 µs)
Separate program and data storage.
Contrary to Harvard architecture designs, however, which use separate buses, the 4004, with its need to keep pin count down,
used a single multiplexed 4-bit bus for transferring: 12-bit addresses
Instruction set contained 46 instructions (of which 41 were 8 bits wide and 5 were 16 bits wide)
Register set contained 16 registers of 4 bits each Internal subroutine stack 3 levels deep.

If you have a 4004 in your pile of junk, you are a lucky guy. 4004's sell at auctions for over $1,000 these days !

http://en.wikipedia.org/wiki/Intel_4004