The name was changed to the Plus 4 and all the applications
were added at the factory. The Plus 4 was redesigned
with a new look and feel. The Plus/4 was the flagship
computer of the line. The Plus/4 had 64 KB of memory
while the C16 and 116 had 16 KB. The Plus/4 had built-in
software, whereas the others did not. The Plus/4 and
C16 had full-travel keyboards; the 116 used a rubber
chiclet keyboard like less-expensive Timex-Sinclair
computers and the original IBM PCjr.
Commodore introduced the Plus/4 in the early to mid
1980s (about 1984ish) to replace the VIC-20 and Commodore
64 models. The machine was a compact case with a full-travel
keyboard sporting four built-in applications (hence
the plus 4 in the name.) The Plus/4 can use some of
the peripherals of the C=64 or the VIC-20 (not included)
, like the famous MPS-801 dot-matrix printer and the
1541 Disk Drive run well with it but it can't use C=64
programs (unfortunately, it cannot use the same joysticks
& Datasette as the C=64/VIC-20).