Author: John T. Easton, University of Minnesota, Minneapolis, MN

Operating System: OS/8 V3 Source Language: PASCAL, PDP-8

MACREL-LINK Memory Required: 24KW Keywords: Language In-

terpreters; PASCAL; Programming Languages; Structured Languages/

Programming; Tools - Application Development; Tools - Software

Development

Abstract: PASCAL - OS/8 is a software system that implements the

programming language PASCAL for the PDP-8 family of minicomputers

running the OS/8 operating system. PASCAL-OS/8 consists of a compiler

(written in PASCAL), a run-time-system with interpreter, and numerous

utility programs and example programs written in PASCAL. Documen-

tation is in printed form, about 135 pages long. PASCAL-OS/8 adheres to

the ISO standard for PASCAL. It installs very simply. The implementation

represents several years of work. It has been run on both PDP-8E and

PDP-12. It is implemented with no PDP-8E dependencies.

Major limitations are: identifiers are distinguished on only the first

eight characters; 24K memory is needed to compile; there is no library

mechanism or assembly language linking mechanism.

Features include: up to 32K memory is utiliized; Post-Mortem-

Display (PMD), execution error traceback is automatic; large programs

may be segmented to fit available memory; several internal device

handlers allow flexible interactive Input/Output; an FPP is used if present

but is not required; it is compatible with two-page system handlers; it can

run well under OS/8 BATCH.

Extensions include: flexible facilities for accessing OS/8 files,

including direct (random or indexed) access files; three-way packed OS/8

character files may be accessed as type TEXT, file of ASCII, or file of

EightBit; Date routine; Execute(string) calls CCL; Halt(message) aborts

execution; otherwise in case statement; others.

Performance is greatly enhanced if the OS/8 system has a fast disk

such as an RK05, and/or if a full 32k memory is available. Performance is

roughly similar to OS/8 BASIC. Installation consists of copyinng some files

to SYS:. Test sites report that PASCAL-OS/8 is complete, easy to install,

and easy to use.

Note: The complete sources for PASCAL-OS/8 currently require a lot of

disk space: RK05 disk for the run-time system sources and supporting

PASCAL tools; RK05 for the compiler sources and supporting PASCAL

tools; RK05 for the documentation source files.

Media Service Charge Code: Manual (EC), DECtape (HB), Floppy

Diskette (KB)

Format: OS/8

Catalog: June 1985