The IBM 5100 and IBM 5110 both share the following overall memory-map:
The IBM 5100 MIM describes specific subroutine in the Executive ROS. These can be invoked from the DCP. An annotated disassembly of the extracted Executive ROS has verified these functions. These are not necessarily the same for the IBM 5110.
From IBM 5100 MIM:
Read/Write Storage Size (page 3-71)
(MIM 3-71) Last byte of RWS 00A8
(not valid until BUP checkpoint H is displayed)
03FF = 16KB
7FFF = 32KB
BFFF = 48KB
FFFF = 64KB
(MIM 3-77) Tape Status Byte 008F (same as 5110 below)
(MIM 3-78) Printer Status Byte A 0055 RAL2 Lo(register 10 of level 2)
(MIM 3-78) Printer Status Byte B 0057 RBL2 Lo(register 11 of level 2)
Last Key Press 0065 Lo(R2L3)
Last Key Press 007B Lo(RDL3) [same as prior entry]NOTE: The available memory is determined during the memory testing during startup. After startup, you could “artificially” reduce the amount of memory (e.g. 64KB down to 16KB). A reason to do this might be for certain programs that were developed that had assumed less memory, or as a development test to verify your own program will function correctly with less memory.
From IBM 5100 MIM:
From IBM 5110 MIM:
(MIM 3-35) Tape Status 008F
(MIM 3-39) Display REGISTERS 0000-01FF
(MIM 3-39) Display NORMAL 0200-05FF
(MIM 4-66) Last byte of RWS 00AA (max. memory) [after BUP I]
(MIM 4-66) RWS available to user 00A8 (memory available)
(MIM 4-66) Printer Status Byte A 0055 RAL2 Lo(register 10 of level 2)
(MIM 4-66) Printer Status Byte B 0057 RBL2 Lo(register 11 of level 2)
(MIM 4-66) Disk Status Byte A 00E8
(MIM 4-66) Disk Status Byte B 00E9
(MIM 4-67 to MIM 4-70 describes the meaning of the status bits)
Last Key Press 0064 R4L3
Last Key Press 0065 R5L3
Last Key Press 0069 R9L3
The following shows the before and after effect on Level 3 registers after a key press:
IBM 5100/5110 Related Acronyms
Summary of common acronyms related to this system::
APL A Programming Language
BASIC Beginners All-Purpose Symbolic Instruction Code
CE Customer engineer
CRC Cyclic Redundancy Check
DCP Diagnostic Control Program
DSP Giagnostic Supervisor Program
IBM International Business Machine
IMF Internal Machine Fix
IOCB Input/Output Control Block
MDI MAPs and Diagnostics Integrated
MIM Maintenance Information Manual
PALM Put All Logic in Microcode
SCAMP Special Computer APL Machine Portable