Development of the PC - Upgrading and Repairing PCs - page 13

Note
Micro Instrumentation and Telemetry Systems was the original name of the company foun-
ded in 1969 by Ed Roberts and several associates to manufacture and sell instruments and
transmitters for model rockets. Ed Roberts became the sole owner in the early 1970s, after
whichhedesignedtheAltair.ByJanuary1975,whentheAltairwasintroduced,thecompany
was called MITS, Inc., which then stood for nothing more than the name of the company.
In 1977, Roberts sold MITS to Pertec, moved to Georgia, went to medical school, and be-
cameapracticingphysician.Consideredbymanytobethe“fatherofthepersonalcomputer,”
Roberts passed away in 2010 after a long bout with pneumonia.
The Altair included an open architecture system bus later called the S-100 bus, so named
because it became an industry standard and had 100 pins per slot. The S-100 bus was
widely adopted by other computers that were similar to the Altair, such as the IMSAI
8080, which was featured in the movie WarGames . The S-100 bus open architecture
meant that anybody could develop boards to fit in these slots and interface to the sys-
tem, and it ensured a high level of cross-compatibility between different boards and sys-
tems. The popularity of 8080 processor-based systems inspired software companies to
write programs, including the CP/M (control program for microprocessors) OS and the
first version of the Microsoft BASIC (Beginners All-purpose Symbolic Instruction Code)
programming language.
IBM introduced what can be called its first personal computer in 1975. The Model 5100
had 16KB of memory, a built-in 16-line-by-64-character display, a built-in BASIC lan-
guage interpreter, and a built-in DC-300 cartridge tape drive for storage. The system's
$8,975 price placed it out of the mainstream personal computer marketplace, which was
dominatedbyexperimenters(affectionatelyreferredtoas hackers )whobuiltlow-costkits
($500 or so) as a hobby. Obviously, the IBM system was not in competition for this low-
cost market and did not sell as well by comparison.
The Model 5100 was succeeded by the 5110 and 5120 before IBM introduced what we
know as the IBM Personal Computer (Model 5150). Although the 5100 series preceded
the IBM PC, the older systems and the 5150 IBM PC had nothing in common. The PC
thatIBMturnedoutwasmorecloselyrelatedtotheIBMSystem/23DataMaster,anoffice
computer system introduced in 1980. In fact, many of the engineers who developed the
IBM PC had originally worked on the DataMaster.
In 1976, a new company called Apple Computer introduced the Apple I, which originally
sold for $666.66. The selling price was an arbitrary number selected by one of Apple's
cofounders, Steve Jobs. This system consisted of a main circuit board screwed to a piece
of plywood; a case and power supply were not included. Only a few of these computers
were made, and they reportedly have sold to collectors for more than $20,000. The Apple