Glossary

APL

A Programming Language
One of the two available programming language for the IBM 5110. The other one is BASIC.

BASIC

Beginners All purpose Symbolic Instruction Code
This is the other available language for the IBM computer. This BASIC dialect has a very rich instruction set for file and data operations.

DCP

Diagnostic Control Program
Builtin monitor program that is called with the key sequence CMD HOLD '-' (keep CMD pressed).
An extended mode with diagnostic routines is called with CMD HOLD '-' '*'.

IMF

Internal Machine Fix

IOCB

I/O Control Block
This block defines the device address, command etc. to be passed to the I/O supervisor routine.

MAP

Maintenance Analysis Procedures

MIM

Maintenance Information Manual

n/c

normally closed
Not to be confused with not connected!

n/o

normally open

ROS

Read Only Storage
The same as the expression ROM, not related to a specific access mode.

RWS

Read/Write Storage
This would be called RAM today which is false. The expression Read/Write Storage is more correct than Random Access Memory since a ROM can be randomly accessed, too. RWS designates every form of read/write memories, e.g. magnetic drum memories like the one in the IBM 650, too, which is not a random access memory.