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CAPS-11

INTRODUCTION

CAPS-11 (Cassette Programming System-11) was a program development system for the PDP-11 using magnetic tape cassettes as a file-structured medium. The system supplied an operating system environment complete with a file system. Data was stored on cassettes in standard RT-11/0S-8 format to ensure compatible data transfers between these DIGITAL operating systems which used the cassette medium. CAPS-8 is the equivalent operating system for the PDP-8 line of computers.

A CAPS-11 cassette is a maqnetic tape device much like that used in an audio cassette tape recorder. The tape itself and the reel it is wound on are enclosed inside a rectanqular plastic case for handlinq and storage.

Design Characteristics

The software includes a resident monitor which does all console terminal, line printer, and cassette I/O. The system allows both block-oriented cassette I/O and paper tape software I/O executive (IOX) compatibility. All devices are interrupt driven, and the user has access to all monitor I/O routines. Also included are a keyboard listener and command string interpreter to allow simple commands to be typed at the console terminal and be passed in a usable form to the system programs.

The system programs include an editor for the creation or modification of cassette source files through text manipulation commands; a relocating assembler featuring conditional assembly and program sectioning directives; a linker which relocates and assigns absolute addresses for all assembled subprograms in a specified job; an on-line debugger to facilitate error detection and testing; and a PIP file utility program which allows the user to copy, rename, and list cassette files.

PIP also supports ASCII or binary level transfers between high-speed paper tape and cassette.

Minimum Hardware Required

Any PDP-11 Processor (except LSI-11 based products) with:

  • KY11-LB Programmer's console (required only for the PDP-11/04 and PDP-11/34)
  • at least 8K words of memory
  • a console terminal
  • TA 11/TU60 dual cassette drive and control
Optional Hardware
  • additional memory to a system total of 28K words
  • LP11 Line Printer
  • PC11 (as supported by PIP) Paper Tape Reader/Punch

Software Components

CAPS-II software is provided on three cassettes; two OBJ cassettes and a System cassette. The OBJ cassettes are used exclusively for changing and building system configurations. A brief description of the software package stored on the System cassette follows:

  1. Monitor - The Keyboard Monitor provides communication between the user and the cassette System executive routines by accepting commands from the console terninal keyboard. The commands allow the user to run system and user programs, load and start programs usinq maximum memory space, and obtain directories of cassettes.
  2. Symbolic Editor - The Editor allows the user to modify or create source files for use as input to the Assembler. The Editor contains powerful text manipulation commands for quick and easy editing.
  3. PAL Assembler - The Assembler (Program Assembly Language) accepts source files in the PAL machine language and generates binary object modules (and/or assembly listings) as output. These object modules can then be linked, loaded and executed.
  4. Linker - The Linker converts relocatable object modules produced by the Assembler into absolute load modules for program loading and execution. The Linker also produces a load map which displays the assigned absolute addresses.
  5. ODT - The ODT (On-Line Debugging Technique) proqram aids the programmer in debugging his object program by allowing the user to examine, change, and run any portion of the program on-line using simple commands typed on the console terminal.
  6. RESMON - The Input/Output package (RESMON) provides routines for all input/output programs in the CAPS-II System. User proqrams can communicate with RESMON (via I/O instructions which utilize RESWlN) to create cassette files and perform all console terminal and line printer I/O.
  7. PIP - (Peripheral Interchange Proqram) allows the user to transfer files from one cassette to another or to the console terminal or line printer and to delete files from cassette. PIP also provides mininal support for paper tape usage by allowing programs to be transferred from cassette to the high-speed paper tape punch and from the high-speed paper tape reader to cassette.

The CAPS-11 User Guide provides more insight into the configuration, commands and fuctions of this operating system.

CAPS-11 and CAPS-11 BASIC distributions are also available from the Software Kit page on the SIMH site.

Guides

Document Name Order Part No. Publication Date Domain
CAPS-11 V1, SPD 11.1.2 AE-3392C-TC August 1977 V1 OS
CAPS-11 User's Guide DEC·II-OTUGA-A·D October 1973 V1 OS
BASIC/CAPS-11, Version 1 SPD 11.5.2 AE-56098-TC August 1977 V1 LANG

Sources

Compiled on 01-14-2026 21:46:02