The Intel 4004 is a 4-bit central processing unit considered to be the first commercially available microprocessor.
A microprocessor is a single integrated circuit (or computer chip)
that merges all the CPU functions of a computer into a single component.
Microprocessors are the heart of modern computers. They’re programmable, meaning they can be
given instructions and return results based on those instructions.
Before their invention, multiple chips were required to do the same thing, often spread
across numerous racks.
Before the 4004, Intel was a memory chip company.
In late 1969, the Nippon Calculating Machine Corporation, also known as Busicom, contracted
Intel to create a dozen custom chips for use in their Busicom 141-PF digital calculator.
Intel didn’t have the manpower to complete the contract as written. That forced Federico
Faggin and his team to think smarter, and came up with a single chip general purpose
design that could do the work of all twelve. The resulting 2,300 transistor chip had as
much processing power as the room-filling ENIAC.
In contrast to today’s multi-gigahertz CPU’s, the 4004 ran at a modest 740 khz.
The 4004 was only one part of the MCS-4 chipset. The 4001 was a required 256 byte ROM.
The 4002 provided an optional 40 bytes of RAM.
The 4003 was a shift register for I/O functions,
also optional.
Intel wisely bought out the rights from the soon-to-be-bankrupt Busicom and decided to
sell the powerful chips commercially.
The 4004 debuted with a price tag of $60 in November of 1971, though rumor has it there
were sales as early as March of that year.
While the Intel 4004 had an important part in computer history, it isn’t the first
microprocessor.
That honor goes to the MP-944, part of the Central Air Data Computer found inside the
F-14 Tomcat. Moreover, the design for the TI TMS 1000 microprocessor was actually completed
before the Intel 4004, but Texas Instruments didn’t sell it to the public until 1974.
The Intel 4004 would eventually be succeeded by the Intel 4040, 8008, 8080, and onward
to the 8086, leading to the famous x86 microprocessor family that powers most desktop computers
to this day.
During the 35th anniversary of the 4004 in 2006, Intel celebrated by releasing a wealth
of technical information to mark the occasion, including mask works, schematics, and other
documentation.
If you’d like to find out more about the Intel 4004, check the links in the description.
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