The IBM PC ( Personal
Computer ) model #5150, was conceived by a team of IBM
engineers sent to Boca Raton, Florida in early 1980. IBM had watched the
microcomputer market grow from its infancy as a kit
building hobby market to a potential billion-dollar industry.
They decided that it was time for the world's largest
computer company to enter the market. The IBM PC debuted
on August 12, 1981 and took the microcomputer market by
storm. It wasn't because the PC was a truly cutting edge
product, because it wasn't. What really created all the
hoopla was that it was built by Big Blue and that set the
standard that every other computer manufacturer was
measured by. The original PC set many standards that can
still be found in today's computers, such as the ISA bus.
You can take a standard 8 bit ISA card from a 19 year old
IBM PC and put it into a modern 400 MHz Pentium II
computer and it will work.
This exhibit is of the early
PC made between 1981 and 1983. You can tell this by
looking at the edge of the motherboard (see above
picture). The early machines came with only 16k or 64k
RAM on the motherboard and were so marked. In April 1983
the motherboard was changed to allow the use of larger
64k RAM chips allowing up to 256k RAM
to be installed.
Both machines were capable of being expanded to 640k
through the use of expansion cards.
This exhibit also has a 20-MB hard drive installed.
Although the original PC did not have this option due
mainly to the fact that the power supply was too small.
Third party manufacturers filled this void with a kit
that replaced the power supply and installed an IDE
controller card. I do have another early model of the PC,
but I prefer to use this one as the exhibit because I run
the original 1985 version 1 of Windows on it.
Another tell tale sign of the
early PC is the use of the INTEL
8088. You will see in
later PCs the use of an AMD licensed version of the 8088.
The
PC was sold in a
number of configurations beginning with the basic model
which had no floppy drives and only 16k of RAM, mass
storage of programs was supposedly to be done with a
cassette tape drive connected to a port on the rear of
the computer. The PC came with Microsoft Cassette BASIC
built in and will default to it if during boot up it does
not detect an operating system on floppy. The exhibit
also has an IBM CGA (color graphics adapter) and is
connected to an IBM #5153 color monitor.
