Series of portable computers, from Commodore, introduced in
1983. The first machine was called Commodore SX-100, but it
eventually became Commodore SX-64, aka Commodore DX-64 (same
machine, two floppy drives).
Basically, these machines were Commodore 64s in a
portability-enhanced chassis, no Datassette port, and built-in
floppy drive and CRT (yes, youngsters, back then LCD displays
were a myth!) OS was hacked a bit: Screen colors were different, the
startup messages were different and loading defaulted to device 8.
Note the subtle naming... Commodore obviously knew that laptop
machines would have a market!
See also: Osborne 1