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RSTS/E



 
 
RSTS (pronounced as "RIST-ess" or "RIST-uhs") is a multi-user
Multi-user

Multi-user is a term that defines an operating system or application software that allows concurrent access by multiple User s of a computer. Time-sharing systems are multi-user systems....
 time-sharing
Time-sharing

Time-sharing refers to sharing a computing resource among many users by Computer multitasking. Its introduction in the 1960s, and emergence as the prominent model of computing in the 1970s, represents a major historical shift in the history of computing....
 operating system
Operating system

An operating system is an interface between hardware and applications; it is responsible for the management and coordination of activities and the sharing of the limited resources of the computer....
, developed by Digital Equipment Corporation
Digital Equipment Corporation

Digital Equipment Corporation was a pioneering United States company in the computer industry. It is often referred to within the computing industry as DEC ....
 ("DEC"), (now part of Hewlett Packard) for the PDP-11
PDP-11

The PDP-11 was a series of 16-bit minicomputers sold by Digital Equipment Corporation from 1970 into the 1990s. Though not explicitly conceived as successor to DEC's PDP-8 computer in the Programmed Data Processor series of computers , the PDP-11 replaced the PDP-8 in many Real-time computing....
 series of 16-bit
16-bit

16-bit architectureThe HP 2100#Descendants and variants , introduced in 1975, was the world's first 16-bit microprocessor.Prominent 16-bit processors include the PDP-11, Intel 8086, Intel 80286 and the WDC 65C816....
 minicomputers. The first version of RSTS (RSTS-11, Version 1) was implemented in 1970 by DEC software engineers
Software engineering

Software engineering is the application of a systematic, disciplined, quantifiable approach to the development, operation, and maintenance of software, and the study of these approaches....
 that developed the TSS-8
TSS-8

TSS-8 was a little time-sharing operating system co-written by Don Witcraft and John Everett at Digital Equipment Corporation in 1967. The operating system ran on the 12-bit PDP-8 computer and was released in 1968....
 time-sharing operating system for the PDP-8
PDP-8

The PDP-8 was the first successful commercial minicomputer, produced by Digital Equipment Corporation in the 1960s. DEC introduced it on 22 March 1965, and sold more than 50,000 systems, the most of any computer up to that date....
. The last version of RSTS (RSTS/E, Version 10.1) was released in September of 1992.






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RSTS (pronounced as "RIST-ess" or "RIST-uhs") is a multi-user
Multi-user

Multi-user is a term that defines an operating system or application software that allows concurrent access by multiple User s of a computer. Time-sharing systems are multi-user systems....
 time-sharing
Time-sharing

Time-sharing refers to sharing a computing resource among many users by Computer multitasking. Its introduction in the 1960s, and emergence as the prominent model of computing in the 1970s, represents a major historical shift in the history of computing....
 operating system
Operating system

An operating system is an interface between hardware and applications; it is responsible for the management and coordination of activities and the sharing of the limited resources of the computer....
, developed by Digital Equipment Corporation
Digital Equipment Corporation

Digital Equipment Corporation was a pioneering United States company in the computer industry. It is often referred to within the computing industry as DEC ....
 ("DEC"), (now part of Hewlett Packard) for the PDP-11
PDP-11

The PDP-11 was a series of 16-bit minicomputers sold by Digital Equipment Corporation from 1970 into the 1990s. Though not explicitly conceived as successor to DEC's PDP-8 computer in the Programmed Data Processor series of computers , the PDP-11 replaced the PDP-8 in many Real-time computing....
 series of 16-bit
16-bit

16-bit architectureThe HP 2100#Descendants and variants , introduced in 1975, was the world's first 16-bit microprocessor.Prominent 16-bit processors include the PDP-11, Intel 8086, Intel 80286 and the WDC 65C816....
 minicomputers. The first version of RSTS (RSTS-11, Version 1) was implemented in 1970 by DEC software engineers
Software engineering

Software engineering is the application of a systematic, disciplined, quantifiable approach to the development, operation, and maintenance of software, and the study of these approaches....
 that developed the TSS-8
TSS-8

TSS-8 was a little time-sharing operating system co-written by Don Witcraft and John Everett at Digital Equipment Corporation in 1967. The operating system ran on the 12-bit PDP-8 computer and was released in 1968....
 time-sharing operating system for the PDP-8
PDP-8

The PDP-8 was the first successful commercial minicomputer, produced by Digital Equipment Corporation in the 1960s. DEC introduced it on 22 March 1965, and sold more than 50,000 systems, the most of any computer up to that date....
. The last version of RSTS (RSTS/E, Version 10.1) was released in September of 1992. RSTS-11 and RSTS/E are usually referred to just as "RSTS" and this article will generally use the shorter form.

Acronyms

  • BTSS (Basic Time Sharing System) -- (never marketed) -- The first name for RSTS.
  • CCL (Concise Command Language)
  • CIL (Core Image Library)
  • CILUS (Core Image Library Update and Save)
  • CLI (Command Line Interpreter)
  • CUSPs (Commonly Used System Programs)
  • DCL (Digital Command Language)
  • DMA (Direct Memory Addressing)
  • DTR (Datatrieve)
  • IOX (Input Output eXecutive)
  • KBM (Keyboard Monitor) -- Analogous to Command Line Interpreter.
  • LAT (Local Area Transport)
  • PBS (Print Batch Services)
  • PPN (Project Programmer Number) -- Analogous to GID and UID in Unix.
  • RDC (Remote Diagnostics Center)
  • ROSS/V (RSTS/E Operating System Simulator for VAX) -- RSTS on the VAX by EG&H.
  • RSTS-11 (Resource Sharing Time Sharing System) -- The first commercial product name for RSTS.
  • RSTS/E (Resource Sharing Timesharing System Extended) -- The current implementation of RSTS.
  • RTS (Run Time System)
  • RTSS (Resource Time Sharing System) -- (never marketed) The second name for RSTS.
  • SATT (Storage Allocation Truth Table)
  • SIL (Saved Image Library)
  • SILUS (Creates Save-Image Libraries)


Development


The 70s
The kernel of RSTS was programmed
Computer programming

Computer programming is the process of writing, testing, debugging/troubleshooting, and maintaining the source code of computer programs. This source code is written in a programming language....
 in the assembly language
Assembly language

An assembly language is a low-level language for programming computers. It implements a symbolic representation of the numeric machine codes and other constants needed to program a particular CPU architecture....
 MACRO-11
MACRO-11

MACRO-11 is an assembly language with Macro facilities for PDP-11 minicomputers from Digital Equipment Corporation . It is the successor to PAL-11 , an earlier version of the PDP-11 assembly language without Macro facilities....
, compiled
Compiler

A compiler is a computer program that transforms source code written in a programming language into another computer language . The most common reason for wanting to transform source code is to create an executable program....
 and installed
Installation (computer programs)

Installation of a computer program is the act and the effect of putting the program in a computer system so that it can be execution .Most programs are supplied in a condensed form intended for sale and distribution....
 to a disk using the CILUS program
Computer program

Computer programs are Instruction for a computer. A computer requires programs to function. Moreover, a computer program does not run unless its instructions are executed by a Central processing unit; however, a program may communicate an Algorithm#Formalization of algorithms to people without running....
, running on a DOS-11 operating system. RSTS booted
Booting

In computing, booting is a Bootstrapping process that starts operating systems when the user turns on a computer system. A boot sequence is the initial set of operations that the computer performs when it is switched on....
 into an extended version of the BASIC programming language which DEC called "BASIC-PLUS
BASIC-PLUS

BASIC-PLUS was an extended dialect of the BASIC programming language developed by Digital Equipment Corporation for use on its RSTS/E time-sharing operating system for the PDP-11 series of 16-bit minicomputers in the early 1970s through the 1980s....
." All of the system software
System software

System software is closely related to, but distinct from Operating System software. It is any computer software that provides the infrastructure over which programs can operate, i.e....
 CUSPS for the operating system, including the programs for resource accounting, login
Logging (computer security)

In computer security, login is the process by which individual access to a computer system is controlled by identification of the User using credentials provided by the user....
, logout and managing the system, were written using BASIC-PLUS. From 1970 to 1973, RSTS ran in only 56K bytes
Kilobyte

Kilobyte is a unit of Computer data storage equal to either 1,024 bytes or 1,000 bytes , depending on context.It is abbreviated in a number of ways: KB, kB, K and Kbyte....
 of memory
Magnetic core memory

Magnetic core memory, or ferrite-core memory, is an early form of random access computer memory. It uses small magnetic ceramic rings, the cores, through which wires are threaded to store information via the Polarity of the magnetic field they contain....
 (64K bytes including the DMA
Direct memory access

Direct memory access is a feature of modern computers and microprocessors that allows certain hardware subsystems within the computer to access system Computer storage for reading and/or writing independently of the central processing unit....
 I/O space). This would allow a system to have up to 16 terminal
Computer terminal

A computer terminal is an electronic or electromechanical computer hardware device that is used for entering data into, and displaying data from, a computer or a computing system....
s with a maximum of 17 jobs. The maximum program size was 16K bytes. By the end of 1973 DEC estimated there were 150 license
License

The verb license or grant license means to give permission. The noun license refers to that permission as well as to the document memorializing that permission....
d systems running RSTS.

In 1973 memory management
Memory management

Memory management is the act of managing computer memory. In its simpler forms, this involves providing ways to allocate portions of memory to programs at their request, and freeing it for reuse when no longer needed....
 support was included in RSTS (now RSTS/E) for the newer DEC PDP-11/40 and PDP-11/45 minicomputers (the PDP-11/20 was only supported under RSTS-11). The introduction of memory management in the newer PDP-11 computers not only meant these machines were able to address four (4) times the amount of memory (18bit addressing, 256K bytes), it also paved the way for the developers to separate user mode
User space

A conventional operating system usually segregates virtual memory into kernel space and user space. Kernel space is strictly reserved for running the kernel , kernel extensions, and some device drivers....
 processes from the core of the kernel.

In 1975 memory management support was again updated for the newer 22bit addressable PDP-11/70. RSTS systems could now be expanded to use as much as two megabyte
Megabyte

Megabyte is a SI prefix-multiple of the unit byte for digital information computer storage or transmission and is equal to 106 bytes....
s of memory running up to 63 jobs. The RTS
Run-time system

In computer science, the runtime system is software that provides services for a running program but which is not itself considered part of the operating system....
 and CCL
OS/8

OS/8 was the primary operating system used on the PDP-8 minicomputer developed by Digital Equipment Corporation of Maynard, Massachusetts, Massachusetts....
 concepts were introduced although they had to be compiled in during "SYSGEN". Multi-terminal service was introduced which would allow a single job the ability to control multiple terminals (128 total). Large-message send/receive and interprocess communication became very sophisticated and efficient. By August there are 1,200 licensed systems.

In 1977 the installation process for RSTS was no longer dependent on DOS-11. The RSTS kernel could now be compiled under the RT-11
RT-11

RT-11 was a small, single-user real-time operating system for the Digital Equipment Corporation PDP-11 family of 16-bit computers. RT-11 was first implemented in 1970 and was widely used for real-time computing systems, process control, and data acquisition across the full line of PDP-11 computers....
 RTS, formatted as a SIL file with RT-11 SILUS, and copied
Copying

Copying is the duplication of information, or an artifact, based only on an instance of that information or artifact, and not using the process that originally generated it....
 to the system or other disks, while the computer
Computer

A computer is a machine that manipulates Data according to a list of Code .The first devices that resemble modern computers date to the mid-20th century , although the computer concept and various machines similar to computers existed earlier....
 was time-sharing. The BASIC-PLUS RTS (as well as RT-11, RSX-11
RSX-11

RSX-11 is a family of real-time operating systems mainly for PDP-11 computers created by Digital Equipment Corporation , common in the late 1970s and early 1980s....
, TECO
Text Editor and Corrector

TECO is a text editor originally developed at the Massachusetts Institute of Technology in the 1960s, after which it was modified by 'just about everybody'....
 and third party RTSs) all ran as user mode processes, independent of the RSTS kernel. A systems manager
System administrator

A system administrator, systems administrator, or sysadmin, is a person employed to maintain and operate a computer system and/or computer network....
 could now decide during the bootstrap phase which RTS he/she wanted as the systems default KBM
Command line interpreter

A command-line interpreter is a computer program that reads lines of text entered by a user and interprets them in the context of a given operating system or programming language....
. There are now 3,100 licensed systems.

In 1978 the final memory management update was included for all machines that could support 22bit addressing. RSTS could now use the maximum amount of memory available to a PDP-11 (4 megabytes). Support was also included for SUPERVISORY mode which made RSTS the first DEC operating system with this capability. DECnet
DECnet

DECnet is a suite of network protocols created by Digital Equipment Corporation, originally released in 1975 in order to connect two PDP-11 minicomputers....
 was also supported as well as remote diagnostics from field service technicians at the RDC in Colorado Springs, Colorado
Colorado Springs, Colorado

Colorado Springs is a Colorado municipalities#Home Rule Municipality that is the county seat and most populous city of El Paso County, Colorado, Colorado, United States....
 (a DEC subscription service). By the end of the decade
Decade

A decade is a period of ten years. The word is derived from the late Latin language decas, from Greek language decas, from deca. The other words for spans of years also come from Latin: lustrum , century , millennium ....
, there are over 5,000 licensed systems.

The 80s
In 1981 support for separate Instruction & Data space for users with Unibus
Unibus

The Unibus was the earliest of several Computer bus technologies used with PDP-11 and early VAX systems manufactured by the Digital Equipment Corporation of Maynard, Massachusetts, Massachusetts....
 machines (PDP-11/44
PDP-11/44

The PDP-11/44, introduced in 1980, was the last of the Digital Equipment Corporation PDP-11 series of minicomputers implemented in discrete logic....
, PDP-11/45, PDP-11/55 and PDP-11/70) provided an extension to the memory constraints of an individual program. Compiling programs to use separate Instruction & Data space would soon give a program up to 64k for instructions, and up to 64k for buffering data. The DCL
DIGITAL Command Language

DCL, the DIGITAL Command Language, is the standard command languageadopted by most of the operating systems that were sold by the former Digital Equipment Corporation ....
 RTS is included as well as support for the newer revision of DECnet III.

In 1983 RSTS/E V8.0-06 included support for the smallest 18-bit PDP-11 sold by DEC (the MicroPDP-11). A pre-generated SIL and CUSPS were included in this distribution to make installation on the MicroPDP-11 easier. DEC sold the pre-generated version on the MicroPDP-11 as MicroRSTS at a reduced price, however users needed to purchase the full version if they had a need to generate their own kernel. The file system was upgraded and given the designation RSTS Directory Structure 1 (RDS1). All previous versions of the RSTS file system are given the designation RDS0. The newer file system is designed to support more than 1700 user accounts. "It is now thought that there are well over 10,000 licensed users and at least an equal number of unlicensed users!".

From 1985 to 1989 RSTS became a mature product in the Version 9 revisions. DCL was installed as the primary RTS and the file system was again upgraded (now RDS1.2) to support new user account features. Passwords were now hashed instead of limited to six (6) characters stored in RADIX-50
RADIX-50

RADIX-50, commonly called Rad-50 or RAD50, is a character encoding created by Digital Equipment Corporation for use on their DECSYSTEM-20, Programmed Data Processor, and VAX computers....
 format. Before Version 9, there was a non-user system account in the project (group) zero (the designation is [0,1]), and all accounts in project number 1 were privileged (not unlike the root account on Unix
Unix

Unix is a computer operating system originally developed in 1969 by a group of American Telephone & Telegraph employees at Bell Labs, including Ken Thompson , Dennis Ritchie, Douglas McIlroy, and Joe Ossanna....
 systems). After Version 9 was released, additional accounts could be created for project zero, and multiple privileges could be individually set for any account. Support for the LAT
Local Area Transport

Local Area Transport is a non-routable networking technology developed by Digital Equipment Corporation to provide connection between the DECserver 90, 100, 200, 300, 700 and DECserver 900 terminal servers and Digital's VAX and DEC Alpha host computers via Ethernet, giving communication between those hosts and serial devices such as video te...
 protocol was included as well as the ability to run the newest version of DECnet IV. These network enhancements gave any user connected to a terminal through a DECserver
DECserver

In computer networking, DECserver initially referred to a highly successful family of asynchronous console server / terminal server / print server products introduced by Digital Equipment Corporation and later referred to a class of UNIX-variant application and file server products based upon the MIPS architecture processor....
 the ability to communicate with a RSTS machine, just as easily as they could with a VAX
VAX

VAX was an instruction set architecture developed by Digital Equipment Corporation in the mid-1970s. A 32-bit complex instruction set computer ISA, it was designed to extend or replace DEC's various Programmed Data Processor ISAs....
 running VMS
OpenVMS

OpenVMS , previously known as VAX-11/VMS, VAX/VMS or VMS, is the name of a high-end computer server operating system that runs on the VAX and DEC Alpha families of computers, developed by Digital Equipment Corporation of Maynard, Massachusetts, Massachusetts , and most recently on Hewlett-Packard systems built around the In...
. The DCL command structure between DEC operating systems also contributed to the familiar look and feel:

"This is not just another pseudo command file processor; it is based on VMS features. The DCL command file processor is fully supported and integrated in RSTS through extensive changes to DCL and the monitor. DCL executes command files as part of your job; therefore, no pseudo keyboard or forcing of commands to your keyboard is necessary (as with ATPK)."


The 90s
In 1994 DEC sold its PDP-11 software business to a company named Mentec , and DEC then essentially discontinued releases of RSTS in order to concentrate on their VAX series of minicomputers.

Mentec would later publicly grant a no-cost license to anyone for non-commercial hobby purpose use of the operating system software developed for the PDP-11, and as the result of the release (for non-commercial use) of a PDP-11 emulator for the IBM-PC, as well as image copies of disk drives of RSTS which exist on the Internet, it is possible for a hobbyist to run RSTS/E on a personal computer in software emulation as fast or faster than it originally ran on the real hardware.

Documentation

The standard complement of documentation manuals that accompanies a RSTS distribution consists of at least 11 large 3-ring binders, 1 small 3-ring binder containing the RSTS/E Quick Reference Guide and 1 paperback copy of Introduction to BASIC AA-0155B-TK. Each of the 11 3-ring binders contain:

Volume 1 General Information and Installation

  • Documentation Directory
  • Release Notes
  • Maintenance Notebook
  • System Installation and Update Guide


Volume 2 System Management

  • System Manager's Guide


Volume 3 System Usage

  • System User's Guide
  • Guide to Writing Command Procedures


Volume 4 Utilities

  • Utilities Reference Manual
  • Introduction to the EDT Editor
  • SORT/MERGE User's Guide
  • RUNOFF User's Guide


Volume 4A Utilities

  • EDT Editor Manual


Volume 4B Utilities

  • Task Builder Reference Manual
  • Programmer's Utilities Manual
  • RT11 Utilities Manual
  • TECO User's Guide


Volume 5 BASIC-PLUS

  • BASIC-PLUS Language Manual


Volume 6 System Programming

  • Programming Manual


Volume 7 MACRO Programming

  • System Directives Manual
  • ODT Reference Manual


Volume 7A MACRO Programming

  • MACRO-11 Language Manual
  • RMS-11 MACRO Programmer's Guide


Volume 8 RMS

  • RMS-11: An Introduction
  • RMS11 User's Guide
  • RMS-11 Utilities


Features

The last Software Product Description from DEC, outlined the following topics as the major features of RSTS/E, Version 10.1:

  • Interactive timesharing.
  • Dynamic allocation of system resources.
  • DCL (Digital Command Language).
  • DCL command file processing.
  • Command line editing and command recall.
  • CCL system manager defined command interface.
  • User and system logical names for devices and/or accounts.
  • System security features.
  • User and job privileges and resource quotas allocated to accounts as required.
  • Batch services provide centralized background execution of DCL command files.
  • Print services provide centralized background printing on terminal printers, line printers, or Terminal Server printers.
  • Operator/Message Services provide dispatching and logging of operator messages and requests sent from users or programs.
  • Extensive file processing including file sharing, protection mechanisms, and virtual (memory) disk support.
  • Integrated system and account management using DCL.
  • Magnetic tape processing (single or multi-volume).
  • Terminal handler designed for interactive environments.
  • Shared common code.
  • Software-maintained cache of frequently-accessed disk data.
  • Intertask communication.
  • Disk file and device backup and restore utilities with streaming support for streaming tape drives supported by RSTS/E.
  • Support for the RQZX1 SCSI adapter on MicroPDP-11/53+, MicroPDP-11/93, and upgraded PDP-11/73
    PDP-11/73

    The PDP-11/73 was the third generation of the PDP-11 series of minicomputers produced by Digital Equipment Corporation to use Large Scale Integration processors....
     and PDP-11/83 systems. Also, support for a specific set of Digital SCSI devices (RZ23L and RZ24L hard disks)using the RQZX1 SCSI adapter.
  • Disk-to-disk volume copying between disks of different sizes and types.
  • System reliability and maintainability features.
  • DCL, RT-11, RSX, and BASIC-PLUS run-time system support.
  • Program Development Tools


History


Operation


Communication
RSTS uses a serial communication connection to interact with the operator. The connection might be a local computer terminal
Computer terminal

A computer terminal is an electronic or electromechanical computer hardware device that is used for entering data into, and displaying data from, a computer or a computing system....
 with a 20 mA
Ampere

The ampere is the International System of Units unit of electric current. The ampere, in practice often shortened to amp, is an SI base unit, and is named after Andr?-Marie Amp?re, one of the main discoverers of electromagnetism....
 current loop
Current loop

A current loop describes two different electrical signalling schemes....
 interface, an RS-232
RS-232

In telecommunications, RS-232 is a standard for serial communications binary data signals connecting between a DTE and a DCE . It is commonly used in computer serial ports....
 interface (either local serial port
Serial port

In computing, a serial port is a serial communication physical interface through which information transfers in or out one bit at a time ....
 or remote connection via modem
Modem

Modem is a peripheral device that modulation an analog carrier wave Signal to encode digital information, and also demodulation such a carrier signal to decode the transmitted information....
), or by an ethernet
Ethernet

Ethernet is a family of Data frame-based computer networking technologies for local area networks . The name comes from the physical concept of the Luminiferous aether....
 connection utilizing DECnet or LAT. As many as 128 terminals (using multi-terminal service) could be connected to a RSTS system, running under a maximum of 63 jobs (depending on the processor
Central processing unit

A central processing unit is an electronic circuit that can execute computer programs. This broad definition can easily be applied to many early computers that existed long before the term "CPU" ever came into widespread usage....
 being used, the amount of memory and disk space, and the system load). Most RSTS systems had nowhere near that many terminals. Users could also submit jobs to be run in batch
Batch file

In DOS, OS/2, and Microsoft Windows, a batch file is a text file containing a series of Command intended to be executed by the Command line interpreter....
 mode. There was also a batch program called "ATPK" that allowed users to run a series of commands on an imaginary terminal (pseudo-terminal) in semi-interactive mode similar to batch commands in MS-DOS
MS-DOS

MS-DOS is an operating system commercialized by Microsoft. It was the most commonly used member of the DOS family of operating systems and was the main operating system for personal computers during the 1980s....
.

Login [Project,Programmer]
Users connected to the system by typing the LOGIN
Logging (computer security)

In computer security, login is the process by which individual access to a computer system is controlled by identification of the User using credentials provided by the user....
 command (or HELLO) at a logged-out terminal and pressing return. Actually, typing any command at a logged-out terminal simply started the LOGIN program which then interpreted the command. If it was one of the commands which were allowed to be used by a user that is not yet logged in ("Logged Out"), then the associated program for that command was CHAINed to, otherwise the message "Please say HELLO" was printed on the terminal. Prior to Version 9, a user could also initiate a 1 line login, however this left your password on the screen for anyone behind you to view (examples follow):

Bye

HELLO 1,2;SECRET

Ready

or

I 1,2;SECRET

Ready

or

LOGIN 1,2;SECRET

Ready

One could determine the status of a terminal from the command responses, printed by the command interpreter. A logged-in user communicating with the BASIC-PLUS KBM was given the prompt "Ready" and a user who is logged out is given the prompt "Bye".

A user would log in by supplying their PPN number and password. User numbers consisted of a project number (this would be the equivalent of a group number in Unix), a comma, and a programmer number. Both numbers were in the range of 0 to 254, with special exceptions. When specifying an account, the project and programmer number were enclosed in brackets. A typical user number could be [10,5] (project 10, programmer 5), [2,146], [254,31], or [200,220], etc. When a user was running a system program while logged out (because the system manager had enabled it) their PPN number was [0,0], and would appear in the SYSTAT CUSP as **,**. Thus that is not a valid account number.

System and user accounts
In every project, the programmer number 0 was usually reserved as a group account, as it could be referenced by the special symbol #. If one's user number were [20,103], a reference to a file name beginning with "#" would refer to a file stored in the account of the user number [20,0]. This feature would be useful in educational environments, as programmer number 0 could be issued to the instructor of a class, and the individuals students given accounts with the same project number, and the instructor could store in his account files marked as shared only for that project number (which would be students in that class only, and no other).

Two special classes of project numbers existed. The project number 0 is generally reserved for system software, and prior to Version 9 there was only 1 project 0 account (named [0,1]). Programmers in the project number 1 were privileged accounts, equivalent to the single account "root" on Unix systems, except that the account numbers [1,0] through [1,254] were all privileged accounts. After Version 9 was released, any account could be granted specific privileges by the systems manager.

The account [0,1] is used to store the operating system file itself, all run-time library systems, and certain system files relating to booting the system (author's comments appear on the right in bold):

DIR [0,1] Name .Ext Size Prot Date SY:[0,1] BADB .SYS 0P < 63> 06-Jun-98 List of bad blocks SATT .SYS 3CP < 63> 06-Jun-98 Bitmap of allocated disk storage INIT .SYS 419P < 40> 06-Jun-98 Operating system loader program ERR .ERR 16CP < 40> 06-Jun-98 System error messages RSTS .SIL 307CP < 60> 06-Jun-98 Operating system itself BASIC .RTS 73CP < 60> 06-Jun-98 BASIC-PLUS run time system RT11 .RTS 20C < 60> 06-Jun-98 RT-11 run time system SWAP .SYS 1024CP < 63> 06-Jun-98 System swap file CRASH .SYS 35CP < 63> 06-Jun-98 System crash dump RSX .RTS 16C < 60> 23-Sep-79 RSX-11 run-time system TECO .RTS 39C < 60> 24-Sep-79 TECO text editor

Total of 1952 blocks in 11 files in SY:[0,1]

(Editor's Note: This directory listing is previous to Version 9.)

The DIR command is an installed CCL equivalent to a RUN command for the DIRECT program. [0,1] is the account number (and directory name) of the operating system storage account. It would be referred to as "project number 0, programmer number 1".

The numbers shown after each file represent its size in disk blocks, a block being 512 byte
Byte

A byte is a basic unit of measurement of Computer storage in computer science. In many computer architectures it is a Byte addressing memory address space....
s or 1/2 kilobyte (K). "C" indicates the file is contiguous (is stored as one file without being separated into pieces, similar to files on a Microsoft Windows
Microsoft Windows

Microsoft Windows is a series of software operating systems and graphical user interfaces produced by Microsoft. Microsoft first introduced an operating environment named Windows in November 1985 as an add-on to MS-DOS in response to the growing interest in graphical user interfaces ....
 system after a drive has been defragmented), while "P" indicates it is specially protected (cannot be deleted, even by a privileged user, unless the P bit is cleared by separate command). The numbers in brackets (like "< 40>") represent the protections for the file, which is always displayed in decimal. Protections indicate if the file may be seen by any other user, by other users with the same programmer number, if the file is read only or if it may be altered by another user, and whether the file may be executed by an ordimary user giving them additional privileges. These protection codes are very similar to the r, w and x protections in Unix
Unix

Unix is a computer operating system originally developed in 1969 by a group of American Telephone & Telegraph employees at Bell Labs, including Ken Thompson , Dennis Ritchie, Douglas McIlroy, and Joe Ossanna....
 and similar operating systems such as BSD and Linux
Linux

Linux is a generic term referring to Unix-like computer operating systems based on the Linux kernel. Their development is one of the most prominent examples of free and open source software collaboration; typically all the underlying source code can be used, freely modified, and redistributed by anyone under the terms of the GNU GPL license...
. Code 60 is equivalent to a private file, code 63 is a private non-deletable file, and 40 is a public file.

Library files are kept in account [1,1] and it is usually referenced by the logical name LB:. The account [1,2] is the system startup account (much like a unix system starting up under root), and contains the system CUSPS that could be referenced by prefixing the CUSP name with a dollar sign ($). "!" is used for account [1,3], "%" for [1,4] and "&" for [1,5]. The account [1,1] also had the special privilege of being the only account where a user logged in under that account is permitted to execute the POKE system call to put values into any memory in the system. Thus the account number [1,1] is the closest equivalent to "root" on Unix-based systems.

Run-Time environments

One of the features of RSTS is the means for the execution of programs and the environment used to run them. The various environments allowed for programming in BASIC-PLUS, the enhanced BASIC Plus 2, and in more traditional programming languages such as COBOL
COBOL

COBOL is one of the oldest programming languages still in active use. Its name is an acronym for COmmon Business-Oriented Language, defining its primary domain in business, finance, and administrative systems for companies and governments....
 and FORTRAN
Fortran

Fortran is a general-purpose programming language, procedural programming language, imperative programming language programming language that is especially suited to numerical analysis and scientific computing....
. These environments were separate from each other such that one could start a program from one environment and the system would switch to a different environment while running a different program, and then return the user to the original environment they started with. These environments were referred to as an RTS. The term for the command line interface
Command line interface

A command-line interface is a mechanism for interacting with a computer operating system or software by typing commands to perform specific tasks....
 that most of these RTS's had was called the KBM. Prior to Version 9, the systems manager needed to define which RTS the system would start under, and it had to be one that would execute compiled programs.

A Systems Manager may also install special CCL commands, which take precedence over all KBM commands (with the exception of DCL). A CCL is analogous to a shortcut to a program on a Windows system or a symbolic link on Unix-based systems. CCL's are installed as a memory-resident command either during startup, or dynamically while the system is running by a system's manager (ie: it is not permanent like a disk file).

When logged in, a user can "SWITCH" to any of these environments, type language statements in the BASIC-PLUS programming language, issue RUN commands to specific programs, or issue a special command called a CCL to execute a program with command options. Most RSTS systems managers generated the kernel to include the "Control-T" one line status option which could tell you what program you were running, under what RTS the program was using, how much memory the program was taking, how much it could expand to, and how much memory the RTS was using.

BASIC-PLUS
Programs written in BASIC-PLUS
BASIC-PLUS

BASIC-PLUS was an extended dialect of the BASIC programming language developed by Digital Equipment Corporation for use on its RSTS/E time-sharing operating system for the PDP-11 series of 16-bit minicomputers in the early 1970s through the 1980s....
 ran under the BASIC RTS, which allowed them up to 32K bytes of memory (out of 64K total). The rest of the memory was used by the BASIC RTS itself. If one wrote programs in a language that permitted true binary executables such as BASIC Plus 2, FORTRAN-IV or Macro Assembler, then the amount of memory available would be 56K (8K allocated to the RTS). The standard BASIC-PLUS prompt is the "Ready" response (example):

new New file name--HWORLD

Ready

10 Print "Hello World" 20 Input "Press Control-T for 1 line status: ";a$ 30 End run HWORLD 10:17 PM01-Jan-08 Hello World Press Control-T for 1 line status: ? 1 KB0 HWORLD+BASIC KB(0R) 2(16)K+14K 0.2(+0.0) +0

Ready

save

Ready

compile

Ready

DIR HWORLD.*/na/ex/si/pr SY:[1,2] HWORLD.BAS 1 < 60> HWORLD.BAC 7C <124>

Total of 8 blocks in 2 files in SY:[1,2]

Ready

DCL
Starting with Version 9, DCL became the primary startup RTS even though it does not have the ability to execute binary programs. This became possible with the advent of the disappearing RSX RTS (see below). DCL was incorporated into all of the recent versions of DEC's operating systems (RSX-11, RT-11, VMS
OpenVMS

OpenVMS , previously known as VAX-11/VMS, VAX/VMS or VMS, is the name of a high-end computer server operating system that runs on the VAX and DEC Alpha families of computers, developed by Digital Equipment Corporation of Maynard, Massachusetts, Massachusetts , and most recently on Hewlett-Packard systems built around the In...
 and later, OpenVMS
OpenVMS

OpenVMS , previously known as VAX-11/VMS, VAX/VMS or VMS, is the name of a high-end computer server operating system that runs on the VAX and DEC Alpha families of computers, developed by Digital Equipment Corporation of Maynard, Massachusetts, Massachusetts , and most recently on Hewlett-Packard systems built around the In...
) for compatibility. The standard DCL prompt is the dollar "$" sign (example):

$ write 0 "Hello World, it is "+F$TIME Hello World, it is 01-Jan-08 10:20 PM $ inquire p1 "Press Control-T for 1 line status:" Press Control-T for 1 line status: 1 KB0 DCL+DCL KB(0R) 4(8)K+24K 0.1(+0.1) -8 $ set verify/debug/watch $ show memory (show memory) (SYSTAT/C)

Memory allocation table: Start End Length Permanent Temporary 0K - 85K ( 86K) MONITOR 86K - 1737K (1652K) (User) 1738K - 1747K ( 10K) (User) DAPRES LIB 1748K - 1751K ( 4K) (User) RMSRES LIB 1752K - 2043K ( 292K) ** XBUF ** 2044K - *** END *** $

RSX
Programs that were written for the RSX RTS such as COBOL, Macro Assembler, or later releases of BASIC Plus 2, could utilize the maximum amount of memory available for a binary program (56K due to the requirements of an RTS needing the top 8K to use for itself). RSTS Version 7 and later allowed the RSX RTS to be included in the kernel, making it completely "disappear" from the user address space, thus allowing 64K bytes of memory for user programs.

Programs got around the limitations of the amount of available memory by using libraries (when permissible), by complicated overlay strategies, or by calling other programs ("Chaining") and passing them commands in a shared memory area called "Core Common," among other practices. When RSX is the default KBM, the standard RSX prompt (both logged in and logged out) is the ">" (or MCR "Monitor Console Routine") sign (example):

>run Please type HELLO >HELLO 1,2;SECRET >run ?What? >help Valid keyboard commands are:

ASSIGN DISMOUNT HELP RUN UNSAVE BYE EXIT MOUNT SHUTUP DEASSIGN HELLO REASSIGN SWITCH

>run CSPCOM CSP>HWORLD=HWORLD CSP>^Z >RUN TKB TKB>HWORLD=HWORLD,LB:CSPCOM.OLB/LB TKB>// >run HWORLD.TSK Hello World Press Control-T for 1 line status: ? 1 KB0 HWORLD+...RSX KB(0R) 7(32)K+0K 0.8(+0.2) +0

>DIR HWORLD.*/na/ex/si/pr SY:[1,2] HWORLD.BAS 1 < 60> HWORLD.BAC 7C <124> HWORLD.OBJ 2 < 60> HWORLD.TSK 25C <124>

Total of 35 blocks in 4 files in SY:[1,2]

>

RT-11
The RT-11 RTS emulated the Single Job version of the RT-11 distribution. Like the RSX emulation, RT-11 occupied the top 8K of memory, leaving the bottom 56K for CUSPS, programs written in FORTRAN-IV or Macro Assembler. When RT-11 is the default KBM, the standard RT-11 prompt (both logged in and logged out) is the "." sign (example):

.VERSION Please type HELLO

.HELLO 1,2;SECRET

.VERSION RT-11SJ V3-03; RSTS/E V8.0

.R PIP *HWORLD.MAC=KB: .MCALL .TTYIN,.PRINT,.EXIT HWORLD: .ASCII /Hello World/<15><12> .ASCIZ /Press Control-T for 1 line status:/ .EVEN

Start: .PRINT #HWORLD .TTYIN .EXIT .END START ^Z *^Z

.R MACRO HWORLD=HWORLD *^Z

.R LINK *HWORLD=HWORLD *^Z

.R HWORLD.SAV Hello World Press Control-T for 1 line status: 1 KB0 HWORLD+RT11 KB(0R) 2(28)K+4K 0.6(+0.2) +0

..DIR HWORLD.*/na/ex/si/pr SY:[1,2] HWORLD.BAS 1 < 60> HWORLD.BAC 7C <124> HWORLD.TSK 25C <124> HWORLD.MAC 1 < 60> HWORLD.OBJ 1 < 60> HWORLD.SAV 2C <124>

Total of 37 blocks in 6 files in SY:[1,2]

.

TECO
One of the most powerful text editors ever developed, the TECO editor, was itself implemented as an RTS to maximize the amount of memory available for the editing buffer, and also because it was first implemented in RSTS V5B, before the release of the general purpose runtime systems (RSX and RT11). TECO was the only RTS distributed with RSTS that did not contain a built in KBM. The user would startup TECO (like any other program) by running a TECO program (TECO.TEC). Most RSTS systems used CCL's to create a file (MAKE filespec), edit a file (TECO filespec), or run a TECO program (MUNG filespec,data). The following program is an example of how TECO could be used to calculate Pi
Pi

Pi or p is a mathematical constant whose value is the ratio of any circle's circumference to its diameter in Euclidean geometry; this is the same value as the ratio of a circle's area to the square of its radius....
 (currently set to 20 digits):

Ready

run TECO *GZ0J\UNQN"E 20UN ' BUH BUV HK QN< J BUQ QN*10/3UI QI< \ +2*10+(QQ*QI)UA B L K QI*2-1UJ QA/QJUQ QA-(QQ*QJ)-2\ 10@I// -1%I > QQ/10UT QH+QT+48UW QW-58"E 48UW %V ' QV"N QV^T ' QWUV QQ-(QT*10)UH > QV^T @^A/ /HKEX$$ 31415926535897932384

Ready

RSTS easter eggs


PDP-11 console lights
One of the nice features that a system manager could compile into the kernel was a rotating display pattern that gave the illusion of 2 snakes chasing each other around the console lights. The normal kernel would give the illusion of 1 snake moving from right to left in the data lights across the bottom. If the system manager also compiled the "lights" object module you would see an additional snake moving from left to right in the address lights across the top. This was accomplished by using supervisory mode in the versions prior to 9.0. RSX also had a similar display pattern that would appear as if 2 snakes were playing chicken and would run into each other in the center of the console.

Stardate
Beginning with version 9.0, an undocumented feature would allow the system manager to change the display of the system date. RSTS now became the first operating system that would display the system date as a set of numbers representing a "Star Date" as commonly known from the TV series Star Trek
Star Trek

Star Trek is an American Science fiction on television entertainment series and media franchise. The Star Trek fictional universe created by Gene Roddenberry is the setting of six television series including the original 1966 Star Trek: The Original Series, in addition to ten feature films with Star Trek to be released on May 8,...
.

RSTS emulations


Charon-11

EG&H
In 1981 Evans Griffiths & Hart would market the ROSS/V product. ROSS/V would allow all user mode processes of RSTS (CUSPS, RTSs and user programs) the ability to run unmodified under VMS on the VAX-11 machines. The code for this emulation handled all of the kernel processes that would normally be handled by a RSTS.SIL running on a PDP-11. The original BASIC-PLUS language that has carried through all versions of RSTS was subcontracted by Evans Griffiths & Hart, Inc. for a fixed price of $10,500.

Ersatz-11
Ersatz-11, a product of , emulates the PDP-11 instruction set running under Windows or Linux. It can be used to run RSTS or other PDP-11 operating systems.

SimH

RSTS mascot


Spike and Albert

Versions


RSTS-11

Following on the heels of TSS-8, the IOX code that would create the first time-sharing operating system for the PDP-11 is named BTSS. The name was again changed (from BTSS to RTSS) as a product with the name BTSS was currently marketed by Honeywell
Honeywell

Honeywell is a major United States multinational corporation list of conglomerates company that produces a variety of consumer products, engineering services, and aerospace systems for a wide variety of customers, from private consumers to major corporations and governments....
. A simple typing mistake changes the name from RTSS to RSTS.

Version Release date Notes
1 Never released  
2A-19 1971 Installed at Carleton College and Seattle Pacific College.
2B June 1971 Installed at the Delaware School Auxiliary Association.
2C October 1971 Enhanced software support (Record I/O).
3A-19 January 1972  
3B May 1972  
3C June 1972 Enhanced software support (UPDATE mode).
4A-12 October 1972 New hardware supported.
4B July 1975 A patched version of V4A with no new features.


RSTS/E

The addition of new memory management support and the ability to install more memory in the PDP-11/40 and PDP-11/45 create a name change. RSTS-11 now becomes RSTS/E.

Version Release date Notes
5A-21 July 1973 Memory management extensions from 64KB to 256KB.
5B-24 November 1974 Multiple SWAP files, RTS and CCL introduced.
5C-01 March 1975 A patched version of V5B with no new features.
6A-02 August 1975 New hardware, 22 bit addressing (2 MB), 63 jobs.
6B-02 February 1977 New hardware, SYSGEN under RT-11, CCL at runtime.
6C-03 February 1978 DECnet Phase II, DTR, DIBOL supported. SUPERVISOR mode.
7.0 August 1978 New hardware, (4 MB), RDC support.
7.1 February 1981 Kernel mode Instruction & Data space support, DECnet Phase III.
7.2 August 1982 New hardware (UDA50 drives).
8.0-06 April 1983 New hardware (MicroPDP-11).
9.0-14 May 1985 New hardware, DCL default, PBS, multiple privs, hashed passwords, new Backup utility, and Stardate.
9.1-05 October 1985 Enhanced hardware support, multi-threaded FIP, LOAD INDEX.
9.2-10 June 1986 New hardware supported.
9.3-20 January 1987 Enhanced hardware support, DECnet Phase IV.
9.4 July 1987 New hardware, Scheduler and Terminal Service improvements.
9.5-08 December 1987 Clustersize increased to 64, BACKUP/DIR added.
9.6 September 1988 LAT support, HELP SPIKE.
9.7 July 1989 New hardware, DV0: at runtime, ANSI PDP-11C available.
10.0 May 1990 Command line history in TTDRV.
10.1 September 1992 Y2K fixes.


Clones in the USSR

  • DOS-KP ("???-??")


See also

  • Asynchronous System Trap
    Asynchronous System Trap

    Asynchronous system trap refers to a mechanism used in several computer operating systems designed by the former Digital Equipment Corporation of Maynard, Massachusetts, Massachusetts....
  • BASIC Plus 2
    BASIC-PLUS

    BASIC-PLUS was an extended dialect of the BASIC programming language developed by Digital Equipment Corporation for use on its RSTS/E time-sharing operating system for the PDP-11 series of 16-bit minicomputers in the early 1970s through the 1980s....
  • Concise Command Language
    OS/8

    OS/8 was the primary operating system used on the PDP-8 minicomputer developed by Digital Equipment Corporation of Maynard, Massachusetts, Massachusetts....
  • Datatrieve
    DATATRIEVE

    DATATRIEVE is a database query and report writer tool that runs on the HP OpenVMS operating system as well as several PDP-11 operating systems....
  • DECnet
    DECnet

    DECnet is a suite of network protocols created by Digital Equipment Corporation, originally released in 1975 in order to connect two PDP-11 minicomputers....
  • Front panel
    Front panel

    A front panel was used on early electronic computers to display and allow the alteration of the state of the machine's internal CPU register and computer memory....
  • Kevin Mitnick
    Kevin Mitnick

    Kevin David Mitnick is a computer security consultant and author, who was incarcerated for more than four years without trial or a bail hearing....
  • Local Area Transport
    Local Area Transport

    Local Area Transport is a non-routable networking technology developed by Digital Equipment Corporation to provide connection between the DECserver 90, 100, 200, 300, 700 and DECserver 900 terminal servers and Digital's VAX and DEC Alpha host computers via Ethernet, giving communication between those hosts and serial devices such as video te...
  • Octal Debugging Technique
    Octal Debugging Technique

    Octal Debugging Technique, or ODT, was the name of several debugger programs originally developed for Digital Equipment Corporation hardware....
  • QIO
    QIO

    QIO is a term used in several computer operating systems designed by the former Digital Equipment Corporation of Maynard, Massachusetts, Massachusetts....
  • Record Management Services
    Record Management Services

    Record Management Services are procedures in the OpenVMS, RSTS/E, RT11 and high-end RSX-11 operating systems that computer program may call to process Computer file and Database record within files....
  • Run-time system
    Run-time system

    In computer science, the runtime system is software that provides services for a running program but which is not itself considered part of the operating system....
  • SYSTAT
    SYSTAT

    SYSTAT is a statistics and statistical graphics software package, developed by Leland Wilkinson in the late 1970's, who was at the time an assistant professor of psychology at the University of Illinois at Chicago....
  • Time-sharing
    Time-sharing

    Time-sharing refers to sharing a computing resource among many users by Computer multitasking. Its introduction in the 1960s, and emergence as the prominent model of computing in the 1970s, represents a major historical shift in the history of computing....
  • Time-sharing system evolution
    Time-sharing system evolution

    The following tables provide links to major early time-sharing operating systems, showing their subsequent evolution.* To avoid listing every multi-user system ever built , the goal here is to list:...


External links