of Microprocessors

132 MUSICAL ApPLICATIONS OF MICROPROCESSORS
the TRS-80, the BASIC interpreter was a simplified integer-only version.
Two features set it apart, however, and, in the author's opinion, were
responsible for its ultimate success. One of these was its much superior
display, which offered full color (when used wirh a color monitor) and, for the
first time in a microcomputer, true bit-mapped graphics at a moderately high
resolution (280 wide X 192 high). The other was the presence, right in its
keyboard enclosure, of eight unused printed circuit board edge connectors
where expansion boards could be easily plugged in. Because of the designers'
background as hobbyists, the Apple's hardware and software were thoroughly
documented, which further accelerated support by other hardware and
software manufacturers and user groups.
During this time, S-IOO computers were also being improved. The
early practice of entering "bootstrap loader" programs through the front
panel switches was replaced by ROM boards, while video display boards
displaced teletypewriters as the primary user interface. Most important,
however, was the increased use offloppy disks for mass storage in place of tape
cassettes. This was made possible by the introduction of the CP/M operating
system in a generic form, which could be easily adapted to the wide and
somewhat disjointed variety of S-IOO systems available. As would be
expected due to their inherently expandable and modular nature, it was
possible to build an S-IOO computer that was much more powerful than the
PET, TRS-80, Apple, and orher similar but less well-known machines. With
memory capacities as large as 64K, S-IOO computers could start being used
for serious business, engineering, and research putposes.
The Second Wave
The introduction and success of these three microcomputers and others
during 1976-77 caught· the attention of numerous entrepreneurs, venture
capitalists, and, to a lesser extent, larger established companies. During the
1978-80 rime period, many, many more integrated microcomputers were
introduced. Simultaneously there was an explosion of computer clubs,
computer stores, computer magazines, and both regional and national
computer shows to support the marketing needs of this sudden increase in
available machines. The split between home/hobby/educational usage and
business applications that barely showed up earlier widened considerably.
The business side showed the most growth probably because, at the
time, the business market was seen to be larger and more immediate than the
home/hobby/educational market. The basic S-IOO hardware architecture and
CP/M operating system dominated the design of second-wave business
microcomputers. In nearly all cases, the microprocessor was a Z-80, memory
was 64K bytes, and the display was a separate 24-line X 80-character
terminal. Floppy disk mass storage was obligatory, but many shifted from 8­
inch diskettes to the less expensive and lower capacity 5-inch size. Costs were