The Tandy 1000 SX used a 7.16 MHz 8088-2 processor, had 384k of memory (upgradeable to 640 KB on the motherboard), came with either one or two 5.25" internal floppy disk drives, and had the light pen port (not a serial port) like the original Tandy 1000. An adjustable potentiometer inside the system controlled the volume of the internal speaker. The Tandy AX was an SX rebadged for sale in Walmart stores. The 1000 SX came with MS-DOS 3.2 and Deskmate II on 5.25" 360kB diskettes.