Hardware Reference
In-Depth Information
II,introducedin1977,helpedsetthestandardfornearlyalltheimportantmicrocomputers
to follow, including the IBM PC.
Themicrocomputerworldwasdominatedin1980bytwotypesofcomputersystems.One
type, the Apple II, claimed a large following of loyal users and a gigantic software base
that was growing at a fantastic rate. The other type, CP/M systems, consisted not of a
single system but of all the many systems that evolved from the original MITS Altair.
These systems were compatible with one another and were distinguished by their use of
the CP/M OS and expansion slots, which followed the S-100 standard. All these systems
were built by a variety of companies and sold under various names. For the most part,
however, these systems used the same software and plug-in hardware. It is interesting to
note that none of these systems was PC compatible or Macintosh compatible, the two
primary standards in place today.
Anewcompetitor looming onthehorizonwasable toseethat tobesuccessful, apersonal
computer needed to have an open architecture, slots for expansion, a modular design, and
healthy support from both hardware and software companies other than the original man-
ufacturer of the system. This competitor turned out to be IBM, which was quite surpris-
ing at the time because IBM was not known for systems with these open-architecture at-
tributes. IBM, in essence, became more like the early Apple, whereas Apple became like
everybody expected IBM to be. The open architecture of the forthcoming IBM PC and
the closed architecture of the forthcoming Macintosh caused a complete turnaround in the
industry.
The IBM Personal Computer
At the end of 1980, IBM decided to truly compete in the rapidly growing low-cost per-
sonal computer market. The company established the Entry Systems Division, located in
Boca Raton, Florida, to develop the new system. The division was intentionally located
far away from IBM's main headquarters in New York, or any other IBM facilities, so that
it would be able to operate independently as a separate unit. This small group consisted
of 12 engineers and designers under the direction of Don Estridge and was charged with
developing IBM's first real PC. (IBM considered the previous 5100 system, developed in
1975, to be an intelligent programmable terminal rather than a genuine computer, even
though it truly was a computer.) Nearly all these engineers had come to the new division
from the System/23 DataMaster project, which was a small office computer system intro-
duced in 1980 and the direct predecessor of the IBM PC.
Much of the PC's design was influenced by the DataMaster design. In the DataMaster's
single-piece design, the display and keyboard were integrated into the unit. Because these
