Berkeley Time-Sharing System - Revision history

Jnc: Move 930 changes to 930 article

2025-09-17T14:10:30Z

Move 930 changes to 930 article

← Older revision		Revision as of 14:10, 17 September 2025
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	The [[kernel]] was named the 'Monitor', and the [[command processor]] the 'Executive'. [[Application]] software included an [[interpreter\|interpretive]] [[programming language]] called 'CAL', inspired by, and very similar to, [[JOSS]].		The [[kernel]] was named the 'Monitor', and the [[command processor]] the 'Executive'. [[Application]] software included an [[interpreter\|interpretive]] [[programming language]] called 'CAL', inspired by, and very similar to, [[JOSS]].

	~~The changes to the 930 were:~~

	* Addition of two additional operating modes for the [[CPU]], "user" and "monitor" (or "executive") to the base "normal" mode (in which the machine operated ''almost'' exactly as a normal 930); the machine started in normal mode (the ''only'' way to enter normal mode), and a special [[instruction]] (the only visible 'non-normality' in normal mode) could switch to monitor mode.
	** Once in user mode, only a 'SYSPOP' (below), a [[trap]], or an [[interrupt]] could transition back to monitor mode.
	* [[Instruction]]s were divided into two classes, ordinary and "privileged" (such as [[halt]] and [[input/output\|I/O]] instructions); "An attempt to execute a privileged instruction while in user mode will result in the execution of a [[no-op\|NOP]] instruction and, subsequently, a trap".
	** Some reserved instructions were used by the system as 'system programmed operators' (SYSPOPs). (Half of the SYSPOPs were allocated to the user, and half to the system.)
	* The user's [[address space]] was divided into 8 [[segment]]s (each 2K [[word]]s long), each of which could be disabled, or independently [[relocation\|relocated]] to any location in [[main memory]] (either for normal read/write access, or read-only).
	** In monitor mode, instructions with the sign bit (normally unused) set used instead user address mapping for that instruction.

	~~In other words, much the same changes as were made to other machines in that era to allow~~
	~~time-sharing at the [[object code]] level.~~

	Supposedly, it featured a limited version of [[PCLSRing]]. From Mark Emmer:		Supposedly, it featured a limited version of [[PCLSRing]]. From Mark Emmer:

Jnc: Changes to the 930 for BTSS

2023-06-11T12:51:47Z

Changes to the 930 for BTSS

← Older revision		Revision as of 12:51, 11 June 2023
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	The '''Berkeley Time-Sharing System''' was a very influential [[time-sharing]] [[operating system]] for an enhanced [[Scientific Data Systems\|SDS]] [[SDS 930\|930]] (effectively the prototype of the later [[SDS 940]]).		The '''Berkeley Time-Sharing System''' was a very influential [[time-sharing]] [[operating system]] for an enhanced [[Scientific Data Systems\|SDS]] [[SDS 930\|930]] (effectively the prototype of the later [[SDS 940]]; the changes (below) prevented a user [[process]] from doing anything which could interfere with another process, or with the operation of the overall system).

	It was produced by [[Project GENIE]] at Berkeley; it was primarily written by L. Peter Deutsch, [[Butler Lampson]], and Chuck Thacker. It was ~~later~~ updated by Ann Hardy at [[Tymshare]] and named TYMCOM; later [[TYMCOM-IX]].		It was produced by [[Project GENIE]] at Berkeley; it was primarily written by L. Peter Deutsch, [[Butler Lampson]], and Chuck Thacker. It later became a product for SDS; it was also updated by Ann Hardy at [[Tymshare]] and named TYMCOM (later [[TYMCOM-IX]]).

	It had a substantial influence on the early design of [[UNIX]]; Ken Thompson had worked on it while he was at Berkeley, and was very familiar with it, and some aspects of ~~Unix~~ (e.g. the split between ''fork()'' and ''exec()'') copy how the Berkeley system operated. It was also one of the influences on [[TENEX]].		It had a substantial influence on the early design of [[UNIX]]; Ken Thompson had worked on it while he was at Berkeley, and was very familiar with it, and some aspects of UNIX (e.g. the split between ''fork()'' and ''exec()'') copy how the Berkeley system operated. It was also one of the influences on [[TENEX]].

	The [[kernel]] was named the 'Monitor', and the [[command processor]] the 'Executive'. [[Application]] software included an [[interpreter\|interpretive]] [[programming language]] called 'CAL', inspired by, and very similar to, [[JOSS]].		The [[kernel]] was named the 'Monitor', and the [[command processor]] the 'Executive'. [[Application]] software included an [[interpreter\|interpretive]] [[programming language]] called 'CAL', inspired by, and very similar to, [[JOSS]].

			The changes to the 930 were:

			* Addition of two additional operating modes for the [[CPU]], "user" and "monitor" (or "executive") to the base "normal" mode (in which the machine operated ''almost'' exactly as a normal 930); the machine started in normal mode (the ''only'' way to enter normal mode), and a special [[instruction]] (the only visible 'non-normality' in normal mode) could switch to monitor mode.
			** Once in user mode, only a 'SYSPOP' (below), a [[trap]], or an [[interrupt]] could transition back to monitor mode.
			* [[Instruction]]s were divided into two classes, ordinary and "privileged" (such as [[halt]] and [[input/output\|I/O]] instructions); "An attempt to execute a privileged instruction while in user mode will result in the execution of a [[no-op\|NOP]] instruction and, subsequently, a trap".
			** Some reserved instructions were used by the system as 'system programmed operators' (SYSPOPs). (Half of the SYSPOPs were allocated to the user, and half to the system.)
			* The user's [[address space]] was divided into 8 [[segment]]s (each 2K [[word]]s long), each of which could be disabled, or independently [[relocation\|relocated]] to any location in [[main memory]] (either for normal read/write access, or read-only).
			** In monitor mode, instructions with the sign bit (normally unused) set used instead user address mapping for that instruction.

			In other words, much the same changes as were made to other machines in that era to allow
			time-sharing at the [[object code]] level.

	Supposedly, it featured a limited version of [[PCLSRing]]. From Mark Emmer:		Supposedly, it featured a limited version of [[PCLSRing]]. From Mark Emmer:
Line 19:		Line 31:
	** [http://bitsavers.org/pdf/sds/9xx/940/ucbProjectGenie/mcjones/R-23_CALrefMan.pdf CAL Reference Manual]		** [http://bitsavers.org/pdf/sds/9xx/940/ucbProjectGenie/mcjones/R-23_CALrefMan.pdf CAL Reference Manual]
	* B. W. Lampson, M. W. Pirtle, W. W. Lichtenberger, ''[http://bwlampson.site/02-UserMachine/Acrobat.pdf A User Machine in a Time-Sharing System]''		* B. W. Lampson, M. W. Pirtle, W. W. Lichtenberger, ''[http://bwlampson.site/02-UserMachine/Acrobat.pdf A User Machine in a Time-Sharing System]''
			* [http://bitsavers.org/pdf/sds/9xx/940/ucbProjectGenie/mcjones/20.10.10.pdf Modifications to the SDS 930 Computer for the Implementation of Time-Sharing]

	[[Category: Operating Systems]]		[[Category: Operating Systems]]

Jnc: Name per original docs

2023-06-10T20:53:09Z

Name per original docs

← Older revision		Revision as of 20:53, 10 June 2023
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	The '''Berkeley ~~Timesharing~~ System''' was a very influential [[time-sharing]] [[operating system]] for an enhanced [[Scientific Data Systems\|SDS]] [[SDS 930\|930]] (effectively the prototype of the later [[SDS 940]]).		The '''Berkeley Time-Sharing System''' was a very influential [[time-sharing]] [[operating system]] for an enhanced [[Scientific Data Systems\|SDS]] [[SDS 930\|930]] (effectively the prototype of the later [[SDS 940]]).

	It was produced by [[Project GENIE]] at Berkeley; it was primarily written by L. Peter Deutsch, [[Butler Lampson]], and Chuck Thacker. It was later updated by Ann Hardy at [[Tymshare]] and named TYMCOM; later [[TYMCOM-IX]].		It was produced by [[Project GENIE]] at Berkeley; it was primarily written by L. Peter Deutsch, [[Butler Lampson]], and Chuck Thacker. It was later updated by Ann Hardy at [[Tymshare]] and named TYMCOM; later [[TYMCOM-IX]].

Jnc: /* External links */ +A User Machine in a Time-Sharing System

2023-06-10T17:28:30Z

External links: +A User Machine in a Time-Sharing System

← Older revision		Revision as of 17:28, 10 June 2023
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	** [http://bitsavers.org/pdf/sds/9xx/940/ucbProjectGenie/R-21_Time-Sharing_System_Reference_Oct68.pdf Reference Manual Time-Sharing System]		** [http://bitsavers.org/pdf/sds/9xx/940/ucbProjectGenie/R-21_Time-Sharing_System_Reference_Oct68.pdf Reference Manual Time-Sharing System]
	** [http://bitsavers.org/pdf/sds/9xx/940/ucbProjectGenie/mcjones/R-23_CALrefMan.pdf CAL Reference Manual]		** [http://bitsavers.org/pdf/sds/9xx/940/ucbProjectGenie/mcjones/R-23_CALrefMan.pdf CAL Reference Manual]
			* B. W. Lampson, M. W. Pirtle, W. W. Lichtenberger, ''[http://bwlampson.site/02-UserMachine/Acrobat.pdf A User Machine in a Time-Sharing System]''

	[[Category: Operating Systems]]		[[Category: Operating Systems]]

Jnc: Upgrade a bit, add ext links

2023-06-10T15:17:43Z

Upgrade a bit, add ext links

← Older revision		Revision as of 15:17, 10 June 2023
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	The '''Berkeley Timesharing System''' was a [[time-sharing]] [[operating system]] for an enhanced [[Scientific Data Systems\|SDS]] [[SDS 930\|930]] (effectively the prototype of the later [[SDS 940]])~~. Primarily written by L. Peter Deutsch, [[Butler Lampson]], and Chuck Thacker. It was updated by Ann Hardy at [[Tymshare]] and named TYMCOM; later [[TYMCOM-IX]]~~.		The '''Berkeley Timesharing System''' was a very influential [[time-sharing]] [[operating system]] for an enhanced [[Scientific Data Systems\|SDS]] [[SDS 930\|930]] (effectively the prototype of the later [[SDS 940]]).

	It ~~had an influence on the early design of~~ [[~~UNIX~~]]; ~~Ken Thompson~~ was ~~very familiar with it~~, and ~~some aspects of Unix (e~~.~~g. the split between ''fork()''~~ and ~~''exec()'') copy how the Berkeley system operated~~.		It was produced by [[Project GENIE]] at Berkeley; it was primarily written by L. Peter Deutsch, [[Butler Lampson]], and Chuck Thacker. It was later updated by Ann Hardy at [[Tymshare]] and named TYMCOM; later [[TYMCOM-IX]].

	It was also one of the influences on [[TENEX]].		It had a substantial influence on the early design of [[UNIX]]; Ken Thompson had worked on it while he was at Berkeley, and was very familiar with it, and some aspects of Unix (e.g. the split between ''fork()'' and ''exec()'') copy how the Berkeley system operated. It was also one of the influences on [[TENEX]].

			The [[kernel]] was named the 'Monitor', and the [[command processor]] the 'Executive'. [[Application]] software included an [[interpreter\|interpretive]] [[programming language]] called 'CAL', inspired by, and very similar to, [[JOSS]].

	Supposedly, it featured a limited version of [[PCLSRing]]. From Mark Emmer:		Supposedly, it featured a limited version of [[PCLSRing]]. From Mark Emmer:
Line 10:		Line 12:

	{{semi-stub}}		{{semi-stub}}

			==External links==

			* [http://bitsavers.org/pdf/sds/9xx/940/ucbProjectGenie/ Project Genie] - documentation at [[Bitsavers]]
			** [http://bitsavers.org/pdf/sds/9xx/940/ucbProjectGenie/R-21_Time-Sharing_System_Reference_Oct68.pdf Reference Manual Time-Sharing System]
			** [http://bitsavers.org/pdf/sds/9xx/940/ucbProjectGenie/mcjones/R-23_CALrefMan.pdf CAL Reference Manual]

	[[Category: Operating Systems]]		[[Category: Operating Systems]]

Jnc: Jnc moved page Berkeley Timesharing System to Berkeley Time-Sharing System: Spelling used in contemporary docs

2023-06-10T14:48:54Z

Jnc moved page Berkeley Timesharing System to Berkeley Time-Sharing System: Spelling used in contemporary docs

← Older revision		Revision as of 14:48, 10 June 2023
(No difference)

Larsbrinkhoff: Further developed as TYMCOM-IX.

2022-11-07T07:04:32Z

Further developed as TYMCOM-IX.

← Older revision		Revision as of 07:04, 7 November 2022
Line 1:		Line 1:
	The '''Berkeley Timesharing System''' was a [[time-sharing]] [[operating system]] for an enhanced [[Scientific Data Systems\|SDS]] [[SDS 930\|930]] (effectively the prototype of the later [[SDS 940]]). Primarily written by L. Peter Deutsch, [[Butler Lampson]], and Chuck Thacker.		The '''Berkeley Timesharing System''' was a [[time-sharing]] [[operating system]] for an enhanced [[Scientific Data Systems\|SDS]] [[SDS 930\|930]] (effectively the prototype of the later [[SDS 940]]). Primarily written by L. Peter Deutsch, [[Butler Lampson]], and Chuck Thacker. It was updated by Ann Hardy at [[Tymshare]] and named TYMCOM; later [[TYMCOM-IX]].

	It had an influence on the early design of [[UNIX]]; Ken Thompson was very familiar with it, and some aspects of Unix (e.g. the split between ''fork()'' and ''exec()'') copy how the Berkeley system operated.		It had an influence on the early design of [[UNIX]]; Ken Thompson was very familiar with it, and some aspects of Unix (e.g. the split between ''fork()'' and ''exec()'') copy how the Berkeley system operated.

Jnc: their 930 was the progenitor of the later 940

2022-05-03T22:51:11Z

their 930 was the progenitor of the later 940

← Older revision		Revision as of 22:51, 3 May 2022
Line 1:		Line 1:
	The '''Berkeley Timesharing System''' was a [[time-sharing]] [[operating system]] for an enhanced [[Scientific Data Systems\|SDS]] [[SDS 930\|930]]. Primarily written by L. Peter Deutsch, [[Butler Lampson]], and Chuck Thacker.		The '''Berkeley Timesharing System''' was a [[time-sharing]] [[operating system]] for an enhanced [[Scientific Data Systems\|SDS]] [[SDS 930\|930]] (effectively the prototype of the later [[SDS 940]]). Primarily written by L. Peter Deutsch, [[Butler Lampson]], and Chuck Thacker.

	It had an influence on the early design of [[UNIX]]; Ken Thompson was very familiar with it, and some aspects of Unix (e.g. the split between ''fork()'' and ''exec()'') copy how the Berkeley system operated.		It had an influence on the early design of [[UNIX]]; Ken Thompson was very familiar with it, and some aspects of Unix (e.g. the split between ''fork()'' and ''exec()'') copy how the Berkeley system operated.
Line 5:		Line 5:
	It was also one of the influences on [[TENEX]].		It was also one of the influences on [[TENEX]].

	Supposedly, it featured a limited version of PCLSRing. From Mark Emmer:		Supposedly, it featured a limited version of [[PCLSRing]]. From Mark Emmer:

	: ''From what I read of the PCLSRing feature, it would be the equivalent of SYSPOPs (System Programmed Operators) in the 940 system. That is, system calls appeared to be atomic while also being interruptible. During an interrupt, the PC would point to the original SYSPOP, perhaps with altered registers for things like counts and memory pointers, reflecting incremental progress with the system call. The user PC would never point to an address within the monitor. On interrupt return, the SYSPOP would be restarted in user space.''		: ''From what I read of the PCLSRing feature, it would be the equivalent of SYSPOPs (System Programmed Operators) in the 940 system. That is, system calls appeared to be atomic while also being interruptible. During an interrupt, the PC would point to the original SYSPOP, perhaps with altered registers for things like counts and memory pointers, reflecting incremental progress with the system call. The user PC would never point to an address within the monitor. On interrupt return, the SYSPOP would be restarted in user space.''

Larsbrinkhoff: Link to Lampson.

2022-04-22T05:01:03Z

Link to Lampson.

← Older revision		Revision as of 05:01, 22 April 2022
Line 1:		Line 1:
	The '''Berkeley Timesharing System''' was a [[time-sharing]] [[operating system]] for an enhanced [[Scientific Data Systems\|SDS]] [[SDS 930\|930]]. Primarily written by L. Peter Deutsch, Butler Lampson, and Chuck Thacker.		The '''Berkeley Timesharing System''' was a [[time-sharing]] [[operating system]] for an enhanced [[Scientific Data Systems\|SDS]] [[SDS 930\|930]]. Primarily written by L. Peter Deutsch, [[Butler Lampson]], and Chuck Thacker.

	It had an influence on the early design of [[UNIX]]; Ken Thompson was very familiar with it, and some aspects of Unix (e.g. the split between ''fork()'' and ''exec()'') copy how the Berkeley system operated.		It had an influence on the early design of [[UNIX]]; Ken Thompson was very familiar with it, and some aspects of Unix (e.g. the split between ''fork()'' and ''exec()'') copy how the Berkeley system operated.

Larsbrinkhoff: Linkify SDS.

2021-10-21T06:10:48Z

Linkify SDS.

← Older revision		Revision as of 06:10, 21 October 2021
Line 1:		Line 1:
	The '''Berkeley Timesharing System''' was a [[time-sharing]] [[operating system]] for an enhanced [[SDS 930]]. Primarily written by L. Peter Deutsch, Butler Lampson, and Chuck Thacker.		The '''Berkeley Timesharing System''' was a [[time-sharing]] [[operating system]] for an enhanced [[Scientific Data Systems\|SDS]] [[SDS 930\|930]]. Primarily written by L. Peter Deutsch, Butler Lampson, and Chuck Thacker.

	It had an influence on the early design of [[UNIX]]; Ken Thompson was very familiar with it, and some aspects of Unix (e.g. the split between ''fork()'' and ''exec()'') copy how the Berkeley system operated.		It had an influence on the early design of [[UNIX]]; Ken Thompson was very familiar with it, and some aspects of Unix (e.g. the split between ''fork()'' and ''exec()'') copy how the Berkeley system operated.