The story
The SX-64 was Commodore's attempt to put the whole Commodore 64 experience into something you could carry. Announced in January 1983 and on sale from December of that year at US$995, it was sold in Europe as the Executive 64 and is often described as the first full-colour portable computer. Portable in this era meant luggable: the machine weighed about 10.5 kg, and its carrying handle folded down to serve as a stand.
Opening the case revealed a 5-inch colour monitor, a built-in 1541-compatible 5.25-inch floppy drive and a small storage bay, with the keyboard clipped over the front as a lid and connected by a cable. Inside was standard C64 hardware: the 6510 processor, 64 KB of RAM, the VIC-II graphics chip and the SID sound chip. Power came from an internal supply with an ordinary mains lead.
Commodore made a few changes for the portable format. There was no cassette port and no RF output for a television, although composite video was still available for an external monitor. The cartridge slot moved to the top of the case, the default screen colours changed to blue text on a white background, and loading and saving pointed to the disk drive by default. A handful of programs and cartridges that expected the standard machine did not behave correctly.
A dual-drive DX-64 was announced but abandoned by early 1985, and a cheaper monochrome SX-100 never shipped. The SX-64 itself sold poorly, held back by its small screen, its weight and a thinner business software library than rival portables. It was discontinued in 1986. Even so, user groups and dealers loved it for demonstrations and disk copying, since a complete working system could be packed up and carried to a meeting. Today it is one of the more sought-after members of the C64 family.