Sharp PC-E500S

The display had more contrast, and the keyboard cover is a (removable) hinged lid (clamshell) instead of plastic slipcase.

The 256 KB system ROM that contained the BIOS, a diagnostic suite,[2] and the BASIC interpreter used to program the device.

It also included an X<>Y exchange key for working with complex numbers and polar to rectangular conversions.

These built-in programs were accessed through a menu system and special function keys.

The Sharp PC-E500 series could store data and programs on memory expansion cards as well as the main RAM.

Main menu with BASIC, CAL, MATRIX, STAT, and ENG mode selection
Diagnostic menu in ROM
PC-E500S with closed lid
Bottom side