Editing IBM PALM processor (section)

== Evolution Across the 5100, 5110 and 5120 ==

'''The PALM module itself does not change between SCAMP, the 5100, the 5110 and the 5120.''' All three production machines use the same PALM controller card — designated '''Card J2''' on the A1 backplane in the 5110 hardware-design documentation. What changes between machines is the surrounding ROS (Read-Only Storage):

* '''SCAMP (1973)''' — ROS holds an IBM 1130 emulator and APL\1130.
* '''IBM 5100 (1975)''' — ROS adds the APLSV interpreter (System/370 APL semantics) and a port of System/3 BASIC.
* '''IBM 5110 (1978)''' — same interpreters plus EBCDIC character set support and IEEE-488 / RS-232 I/O ROS.
* '''IBM 5120 (1980)''' — same interpreters, both APL and BASIC in ROM as standard, plus support for built-in 8-inch floppy drives.

This page treats the PALM hardware as constant; the differences are in the executable and language ROS that wrap it, not in PALM itself.