Hardware Reference
In-Depth Information
Integrated Circuits
The third generation of modern computers is known for using integrated circuits instead
of individual transistors. Jack Kilby at Texas Instruments and Robert Noyce at Fairchild
are both credited with having invented the
integrated circuit (IC)
in 1958 and 1959. An
ICisasemiconductor circuit thatcontains morethanonecomponent onthesamebase(or
substratematerial),whichareusuallyinterconnectedwithoutwires.ThefirstprototypeIC
constructed by Kilby at TI in 1958 contained only one transistor, several resistors, and a
capacitor on a single slab of germanium, and it featured fine gold “flying wires” to inter-
connectthem.However,becausetheflyingwireshadtobeindividuallyattached,thistype
of design was not practical to manufacture. By comparison, Noyce patented the “planar”
IC design in 1959, where all the components are diffused in or etched on a silicon base,
includingalayerofaluminummetalinterconnects.In1960,Fairchildconstructedthefirst
planarIC,consistingofaflip-flopcircuitwithfourtransistorsandfiveresistorsonacircu-
lardieonlyabout20mm
2
insize.Bycomparison,theIntelCorei7quad-coreprocessorin-
corporates 731 million transistors (and numerous other components) on a single 263mm
2
die!
History of the PC
The fourth generation of the modern computer includes those that incorporate micropro-
cessors in their designs. Of course, part of this fourth generation of computers is the per-
sonalcomputer,whichitselfwasmadepossiblebytheadventoflow-costmicroprocessors
and memory.
Birth of the Personal Computer
In 1973, some of the first microcomputer kits based on the 8008 chip were developed.
These kits were little more than demonstration tools and didn't do much except blink
lights.InApril1974,Intelintroducedthe8080microprocessor,whichwas10timesfaster
thantheearlier8008chipandaddressed64KBofmemory.Thiswasthebreakthroughthat
the personal computer industry had been waiting for.
A company called MITS introduced the Altair 8800 kit in a cover story in the January
1975 issue of
Popular Electronics
. The Altair kit, considered by many to be the first per-
sonal computer, included an 8080 processor, a power supply, a front panel with a large
number of lights, and 256 bytes (not kilobytes) of memory. The kit sold for $395 and had
to be assembled. Assembly back then meant you got out your soldering iron to actually
finish the circuit boards—not like today, where you can assemble a system of premade
components with nothing more than a screwdriver.
