IBM 5100/5110 Memory Map and Acronyms

BACK TO IBM 5100

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

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