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| (click on picture |
| Introduced | August 12, 1981 |
| Discontinued | April 2, 1987 |
| Introduction Price |
| 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. The original PC did not have a hard drive option available through IBM, the power supply was too small, (only 63 watts), to support a hard drive option. Third party manufacturers filled this void with a kit that replaced the power supply and installed an IDE controller card. The original power supplies can be identified by the all black paint and the red warning sticker on top. (see above picture) Replacement power supplies will be an unpainted silver or gold color. 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. |
| System Architecture | |
| Microprocessor | Intel 8088 used in early models (AMD was used in later models) |
| Clock speed | 4.77Mhz |
| Bus type | ISA (Industry Standard Architecture) |
| Bus width | 8-bit |
| Interrupt levels | 8 (6 usable) |
| DMA channels | 4 (3 usable) |
| Memory | |
| Standard on system board | 16k, 64k, or 256k(only after 1983) |
| Maximum on system board | 64k or 256k |
| Maximum total memory | 640k |
| Memory speed and type | 200ns dynamic ram chips |
| System board memory socket type | 16 pin DIP |
| Number of memory module sockets | 27 (3 banks of 9 chips) |
| Memory used on system board | 1 soldered bank of 9-16k X
1(early) or 64k X 1(later) bit chips. 27-16k X 1 for early PC's (Pre 1983) or 27-64k X 1 for PC's after 1983 |
Standard Features |
Disk Storage |
|||
| ROM size | 40k | ***** | Internal disk and tape drive bays | 2 full height |
| Optional math coprocessor | 8087 | ***** | Standard floppy drives | 1 X 360k |
| Standard graphics | none | Optional floppy drives: | ||
| Parallel printer ports | none | * 5 1/4 inch 360k | Optional | |
| RS232C serial ports | none | * 5 1/4 inch 1.2MB | No | |
| Mouse ports | none | * 3 1/2 inch 720k | Optional | |
| UART chip used | NS8250B | * 3 1/2 inch 1.44MB | No | |
| Maximum speed | 9600bps | * 3 1/2 inch 2.88MB | No | |
| CMOS real time clock | no | Hard disk controller included | No | |
| CMOS RAM | none | |||
Expansion Slots |
Keyboard Specs. |
|||
| Total adapter slots | 5-8 bit | Number of keys | 83 | |
| Number of 8/16/32 bit slots | 5/0/0 | Keyboard cable length | 6 feet | |
Physical Specs. |
Environmental Specs. |
|||
| Dimensions: | Power supply output | 63.5 watts | ||
| * Height | 5.5 inches | Operating voltage @ 60 Hz | 104-127VAC | |
| * Width | 19.5 inches | Maximum current | 2.5 amps | |
| * Depth | 16.0 inches | |||
| * Weight | 25 pounds |
