What is the Apple ///?

The Apple /// (code name: SARA) was the first computer ever
designed from the ground-up by Apple Computer as a company. It
included many of the "extras" one had to buy separately for the Apple
//: an 80 column card, a serial card, larger memory, etc. In
addition, it came with the most advanced operating system for small
computers of its day: SOS or the Sophisticated Operating System. So
good, in fact, that Apple later based its ProDos Operating System for
the Apple //e, //c, and //gs on SOS. The Macintosh's HFS, or
Heirarchical Filing System was also based on a similar system that
was part of SOS.

Design work on the Apple /// started in late 1978 under the
guidance of Dr. Wendell Sander. It was officially introduced at the
National Computer Conference in May, 1980. But the machine was never
properly tested and when shipments of SARA started in the fall there
were almost immediate problems. Of primary concern: the chips would
pop out of their sockets after only a few hours (primarily due to
heat). This lead to the famous "two-inch drop", where owners would
pick their machine up and drop it two inches to reset the chips. Such
a short-term solution was not totally satisfactory, however, and
Apple ended up relacing every main circuit ("mother") board. (In
fact, Apple's policy through June, 1981 was immediate replacement -
no questions asked.)

And there were other problems - a promised built-in clock/calendar
chip did not work, and there was very little software (people
complained "I spent $4000+ and got Visicalc and a paperweight!")

The problems hurt Apple's reputation. By December, 1981 Apple
"reintroduced" the Apple III - a revamped system with all or most of
the serious problems gone. But the damage had already been done. The
IBM PC was introduced in August, 1981 - between the old III and the
"fixed" III. And while the PC did not meet immediate acceptance, it
was helped along by the ///s problems.

With the Lisa already out and the Macintosh in development, Apple
was unsure what to do about the ///. They finally decided to release
an updated version, the Apple III Plus - but it did not hit dealer's
shelves until December 1983. The /// Plus had a new //e-style
keyboard and a few other upgrades (power supply/video interlace) and
was problem-free. Yet the entire Apple III line was discontinued only
four months later! All in all, some 100,000 machines had actually
been built.

Here's a visual timeline graph to make things clear. Note that
each notch in the graph represents two months.

1980
|-
|-
|- <--------------- Apple III
|-
|-
1981 |-
|-
|-
|-
|- <--------------- IBM PC
|-
1982 |- <--------------- Apple III (fixed version)
|-
|-
|-
|-
|-
1983 |-
|- <--------------- Lisa, Apple IIe
|-
|-
|-
|-
1984 |- <--------------- Apple III Plus
|- <--------------- Macintosh
|- <--------------- Apple IIc [Apple III discontinued]
|-
|-
|- <--------------- Mac 512
1985 |-
.