Most of the PowerBook 100's internal components were based on its predecessor, the Macintosh Portable. It included a Motorola 68HC000 16 MHz processor, had 2 MB memory, no floppy disk drive, and cost approximately $2,300. An external floppy disk drive was available for $279. The dimensions of the PowerBook 100 were an improvement over the Portable. It was deep, wide, and high, compared to the Portable, which was deep, wide and high. Another significant difference was the less expensive passive matrix display used instead of the sharper active matrix used on the Portable (and the 170). The PowerBook 100 included the System 7.0.1 operating system as standard, with support for all versions up to System 7.5.5. Apple, however, released System 6.0.8L, which allowed the PowerBook 100 to run System 6. It could also be used with some earlier System 6 versions, although Apple did not officially support this.