TOPS-10

TOPS-10
Company type	Operating system
Industry	Computer software
Predecessor	Monitor (PDP-6 and PDP-10)
Founded	1967
Founder	Digital Equipment Corporation (DEC)
Defunct	1988
Headquarters	Nashua, United States
Products	TOPS-10 operating system
Owner	Digital Equipment Corporation (DEC)

TOPS-10 (an abbreviation for Timesharing / Total Operating System-10) is an obsolete operating system developed by Digital Equipment Corporation (DEC) specifically for the PDP-10 (DECsystem-10) series of mainframe computers. Initially launched in 1967, TOPS-10 originated from predecessor "Monitor" software designed for the PDP-6 and PDP-10 platforms, with the TOPS-10 designation formally adopted in 1970.

Overview

TOPS-10 incorporated support for shared memory, facilitating early multiplayer computer game innovation such as DECWAR, a real-time, text-based game inspired by Star Trek. Additionally, it was the platform for the original Multi User Dungeon, known as MUD, which served as a foundational influence on contemporary MMORPGs.

The operating system included FORUM, one of the earliest chat programs similar to CB Simulator, which introduced multi-user interaction and helped shape subsequent chat services like those offered by CompuServe.

TOPS-10 provided a comprehensive application programming interface through UUOs (Unimplemented User Operations), which functioned as OS calls mimicking machine-level instructions. This sophisticated Monitor Call API streamlined system programming tasks on DECsystem-10 machines.

Its process scheduler utilized prioritized run queues to manage task execution based on assigned priorities. Furthermore, the OS ensured independence between user files and devices, thereby increasing adaptability for enterprise applications.

Commands

The following list comprises commands available within TOPS-10:

ASSIGN
ATTACH
BACKSPACE
BACKUP
CCONTINUE
COMPILE
CONTINUE
COPY
CORE
CPUNCH
CREATE
CREDIR
CREF
CSTART
D(eposit)
DAYTIME
DCORE
DDT
DEASSIGN
DEBUG
DELETE
DETACH
DIRECTORY
DISABLE
DISMOUNT
DSK
DUMP
E(xamine)
EDIT
ENABLE
EOF
EXECUTE
FILCOM
FILE
FINISH
FUDGE
GET
GLOB
HALT
HELP
INITIA
JCONTINUE
KJOB
LABEL
LIST
LOAD
LOCATE
LOGIN
MAKE
MERGE
MIC
MOUNT
NETWORK
NODE
NSAVE
NSSAVE
OPSER
PJOB
PLEASE
PLOT
PRESERVE
PRINT
PROTECT
PUNCH
QUEUE
QUOLST
R
REASSIGN
REATTACH
REENTER
RENAME
RESOURCES
REWIND
RUN
SAVE
SSAVE
SCHED
SEND
SET
SKIP
START
SUBMIT
SYSTAT
TECO
TIME
TPUNCH
TYPE
UNLOAD
USESTAT
VERSION
WHERE
ZERO

Release history

The original Monitor software for the PDP-6 was introduced in 1964, with compatibility for the PDP-10's KA10 processor incorporated in version 2.18 released in 1967. The TOPS-10 label was first used starting with version 5.01 in 1970. Version 6.01, issued in May 1974, brought in demand paging and virtual memory capabilities that allowed programs exceeding physical memory size to run. Beginning with release 7.00, the system transitioned from a master/slave arrangement to symmetrical multiprocessing. The last official update, version 7.04, arrived in 1988.

TOPS-10 today

TOPS-10 remains accessible to enthusiasts through a Hobbyist's License, enabling ongoing exploration and usage. Nowadays, operating TOPS-10 generally requires emulators paired with OS images sourced from original distributions or preserved tape archives. A notable example includes Paul Allen, who preserved a DECsystem-2065 running TOPS-10 within his collection of historic computing systems.

Programming languages supported

The TOPS-10 package came with the MACRO-10 assembler as a standard component.

Various programming languages were available on TOPS-10 as additional layered products:

ALGOL, provided as ALGOL-10 v10B, serving as a general-purpose compiler
APL, delivered as APL-SF V2, functioning as an interpreter for mathematical applications
BASIC, offered as BASIC-10 v17F, an interpreter for general computing tasks
BLISS, available in BLISS-10 and BLISS-36 versions, compilers designed for systems programming
COBOL, supplied as COBOL-68 and COBOL-74 compilers tailored for business applications
Fortran, presented as FORTRAN-10 v11, a compiler optimized for numerical computations

Additional languages were introduced by members of DECUS:

FOCAL, known as FOCAL-10
Forth, a threaded interpreted language
IMP72
Lisp, an interpreter commonly used in artificial intelligence development
Pascal, a compiler frequently employed in educational settings
PILOT
SAM76
Simula, a compiler intended for simulation and modeling purposes
SNOBOL, an interpreter specialized in string manipulation
BCPL, a compiler created at Essex University

User utilities available

Key utilities provided on TOPS-10 included:

RMS (Records Management Services)
IQL (Interactive Query Language)
DBMS-10 (a CODASYL Database Management System)

Prominent games developed for TOPS-10

ADVENT
DECWAR
FORUM
HAUNT, an early role-playing game title
Mac Hack, a chess program developed by Richard Greenblatt
MUD

Legacy

The design of MS-DOS was heavily influenced by TOPS-10, incorporating elements like three-letter file extensions (for example, EXE and TXT), the use of the asterisk () wildcard character, and the slash () to denote command switches, among other features.