UNIX Second Edition - Revision history

Jnc: Mention archaeology without kernel source

2023-10-20T01:54:54Z

Mention archaeology without kernel source

← Older revision		Revision as of 01:54, 20 October 2023
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	}}		}}

	'''UNIX Second Edition''' (often referred to as '''UNIX V2''' or '''V2 UNIX''' - 'Unix' was still normally given in all capital letters at this point in time) was an early version of [[UNIX]]. ~~There were 10 instances of UNIX running inside Bell at this point. It still ran on~~ the [[~~PDP-11/20~~]] ~~model of the PDP-11~~.		'''UNIX Second Edition''' (often referred to as '''UNIX V2''' or '''V2 UNIX''' - 'Unix' was still normally given in all capital letters at this point in time) was an early version of [[UNIX]]. The [[source code]] for the [[kernel]] has been completely lost, so it is not possible to make authoritative, detailed, statements about it; but documentation, and source for some commands still exists, which allows technological archaeologists to draw some conclusions about it.

	~~Support for protection (and relocation - i~~.~~e. memory that looks, to user code, as if it's at 0, but is actually at, say, 060000 in physical terms) in PDP-11 UNIX ''pre-dates''~~ the [[PDP-11/45]] ~~(the first PDP-11~~ model on which it was a standard). [[Digital Equipment Corporation\|DEC]] had a rare, and now almost forgotten "Memory Protect & Relocate" [[memory management]] option for the -11/20, the [[KS11 Memory Protection and Relocation option\|KS11]]. Some of the -11~~/20's running V2 UNIX had a KS11 - "the current system, which has relocation and protection hardware". ([http://squoze~~.~~net/UNIX/v2man/man5/core core(V)])~~		There were 10 instances of UNIX running inside Bell at this point. It still ran on the [[PDP-11/20]] model of the PDP-11.

	~~One big question concerns details of how the process' address space was laid out - the man pages~~ for ld(~~III)~~ and ~~exec(II) simply say nothing at all~~. ~~With the KS11~~, ~~one can assume~~ it ~~started~~ at 0 - ~~but who knows? Without~~ the ~~KS11, it must have started at a higher address~~ (~~since on~~ the PDP-11, [[~~interrupt vector~~]]~~s are in low memory)~~, ~~as on~~ [[~~MINI-UNIX#Implementation_details\|MINI-UNIX~~]]~~; but again~~, ~~neither V1's ld(III) nor exec(II) mentions this detail. One could work it out from~~ the V1 [[~~kernel~~]] ~~source~~, ~~if one is ''really'' interested.~~..		Support for protection (and relocation - i.e. memory that looks, to user code, as if it's at 0, but is actually at, say, 060000 in physical terms) in PDP-11 UNIX actually ''pre-dates'' the later [[PDP-11/45]] (the first PDP-11 model on which it was a standard). [[Digital Equipment Corporation\|DEC]] had a rare, and now almost forgotten "Memory Protect & Relocate" [[memory management]] option for the -11/20, the [[KS11 Memory Protection and Relocation option\|KS11]]. Some of the -11/20's running V2 UNIX had a KS11 - "the current system, which has relocation and protection hardware". ([http://squoze.net/UNIX/v2man/man5/core core(V)])

	Some ~~also had~~ [[KE11-A Extended Arithmetic Element]]s. (It's important to ~~remember~~ that not all the machines running UNIX would have had their hardware updated simultaneously: e.g. the patent group's -11/20 would not have needed the KS11 as much, since it was running mature [[application]]s. So V2 UNIX was probably conditionalized to run with and without the KS11~~. V1 used the KE11-A, and was not conditionalized to be able to run without it, though~~.)		One big question concerns details of how a [[process]]' [[address space]] was laid out - the man pages for ld(I) and exec(II) simply say nothing about this at all. With the KS11, one can assume it started at 0 - but who knows? Without the KS11, it must have started at a higher address (since on the PDP-11, [[interrupt vector]]s are in low memory), as on [[MINI-UNIX#Implementation_details\|MINI-UNIX]]; but again, neither V1's ld(I) nor exec(II) mentions this detail. One could work it out from the V1 kernel source (which ''does'' still exist, if one is ''really'' interested...

			Some possibly did not have a [[KE11-A Extended Arithmetic Element\|KE11-A]] (mandatory in V1 - V1 used the KE11-A, and was not conditionalized to be able to run without it). (It's important to realize that not all the machines running UNIX would have had their hardware updated simultaneously: e.g. the patent group's -11/20 would not have needed the KS11 as much, since it was running mature [[application]]s. So V2 UNIX was probably conditionalized to run with and without the KS11.)

	The -11/45 was apparently expected in the near future; V2 seems to have started looking forward to it - "a trap is simulated by the [[floating point]] simulator" ([http://squoze.net/UNIX/v2man/man5/core core(V)]); "if they correspond to 11/45 floating point [[instruction]]s". ([http://squoze.net/UNIX/v2man/man3/fptrap fptrap(III)]) It is possible that they already had the -11/45 at this point, but one would tend to doubt it: "immediate mode ((pc)+) is not supported, since the PDP-11/45 handbook is not clear on what to do about it." (If they had it, a simple experiment would have produced the answer.) And "Double precision results are probably less correct than the hardware will be" (note tense). (All from fptrap(III).)		The -11/45 was apparently expected in the near future; V2 seems to have started looking forward to it - "a trap is simulated by the [[floating point]] simulator" ([http://squoze.net/UNIX/v2man/man5/core core(V)]); "if they correspond to 11/45 floating point [[instruction]]s". ([http://squoze.net/UNIX/v2man/man3/fptrap fptrap(III)]) It is possible that they already had the -11/45 at this point, but one would tend to doubt it: "immediate mode ((pc)+) is not supported, since the PDP-11/45 handbook is not clear on what to do about it." (If they had it, a simple experiment would have produced the answer.) And "Double precision results are probably less correct than the hardware will be" (note tense). (All from fptrap(III).)
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	==Source==		==Source==

	A copy of Second Edition does not seem to be extant. [[The Unix Heritage Society\|TUHS]] claims to have the [[source code]] for some of its user code: an early version of the first [[C programming language\|C]] [[compiler]] (C was just being defined at the point in time), and many commands (but see below). The 'UNIX Programmer's Manual: Second Edition' is also available.		As mentioned, a complete copy of Second Edition does not seem to be extant. [[The Unix Heritage Society\|TUHS]] claims to have the [[source code]] for some of its user code: an early version of the first [[C programming language\|C]] [[compiler]] (C was just being defined at the point in time), and many commands (but see below). The 'UNIX Programmer's Manual: Second Edition' is also available.

	The 'cmd' directory at TUHS actually seems to be for [[UNIX Third Edition\|V3]] (see discussion there). However, the sources for some V2 commands were reconstructed by [[decompilation\|decompiling]] the [[object code]] for some that were located in an old dump (in the 's2-bits.tar.gz' file in the TUHS archive, below). The binaries seem to be a mixture of 'naked' binaries, with some in V1 and V2 [[UNIX a.out file\|a.out formats]].		The 'cmd' directory at TUHS actually seems to be for [[UNIX Third Edition\|V3]] (see discussion there). However, the sources for some V2 commands were reconstructed by [[decompilation\|decompiling]] the [[object code]] for some that were located in an old dump (in the 's2-bits.tar.gz' file in the TUHS archive, below). The binaries seem to be a mixture of 'naked' binaries, along with some in V1 and V2 [[UNIX a.out file\|a.out formats]].

	==External links==		==External links==

Jnc: /* External links */ +TUHS wiki link

2023-10-18T18:50:46Z

External links: +TUHS wiki link

← Older revision		Revision as of 18:50, 18 October 2023
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	* [https://www.tuhs.org/Archive/Distributions/Research/1972_stuff 1972 stuff] - the source for the above		* [https://www.tuhs.org/Archive/Distributions/Research/1972_stuff 1972 stuff] - the source for the above
	** [https://www.tuhs.org/Archive/Distributions/Research/1972_stuff/Readme Readme] - a discussion of what's there		** [https://www.tuhs.org/Archive/Distributions/Research/1972_stuff/Readme Readme] - a discussion of what's there
			* [https://wiki.tuhs.org/doku.php?id=systems:2nd_edition Second Edition Unix]
	* [https://minnie.tuhs.org/mailman3/hyperkitty/list/tuhs@tuhs.org/thread/Y5CHHVMQY3JUOKI4PD7OVB4FBD4ILV2O/ S2-bits V2 Source Code Restoration]		* [https://minnie.tuhs.org/mailman3/hyperkitty/list/tuhs@tuhs.org/thread/Y5CHHVMQY3JUOKI4PD7OVB4FBD4ILV2O/ S2-bits V2 Source Code Restoration]
	* [https://gitlab.com/segaloco/v2src v2src]		* [https://gitlab.com/segaloco/v2src v2src]

Jnc: Use common man ref format

2023-10-18T17:51:53Z

Use common man ref format

← Older revision		Revision as of 17:51, 18 October 2023
Line 12:		Line 12:
	'''UNIX Second Edition''' (often referred to as '''UNIX V2''' or '''V2 UNIX''' - 'Unix' was still normally given in all capital letters at this point in time) was an early version of [[UNIX]]. There were 10 instances of UNIX running inside Bell at this point. It still ran on the [[PDP-11/20]] model of the PDP-11.		'''UNIX Second Edition''' (often referred to as '''UNIX V2''' or '''V2 UNIX''' - 'Unix' was still normally given in all capital letters at this point in time) was an early version of [[UNIX]]. There were 10 instances of UNIX running inside Bell at this point. It still ran on the [[PDP-11/20]] model of the PDP-11.

	Support for protection (and relocation - i.e. memory that looks, to user code, as if it's at 0, but is actually at, say, 060000 in physical terms) in PDP-11 UNIX ''pre-dates'' the [[PDP-11/45]] (the first PDP-11 model on which it was a standard). [[Digital Equipment Corporation\|DEC]] had a rare, and now almost forgotten "Memory Protect & Relocate" [[memory management]] option for the -11/20, the [[KS11 Memory Protection and Relocation option\|KS11]]. Some of the -11/20's running V2 UNIX had a KS11 - "the current system, which has relocation and protection hardware" ([http://squoze.net/UNIX/v2man/man5/core core(V)]).		Support for protection (and relocation - i.e. memory that looks, to user code, as if it's at 0, but is actually at, say, 060000 in physical terms) in PDP-11 UNIX ''pre-dates'' the [[PDP-11/45]] (the first PDP-11 model on which it was a standard). [[Digital Equipment Corporation\|DEC]] had a rare, and now almost forgotten "Memory Protect & Relocate" [[memory management]] option for the -11/20, the [[KS11 Memory Protection and Relocation option\|KS11]]. Some of the -11/20's running V2 UNIX had a KS11 - "the current system, which has relocation and protection hardware". ([http://squoze.net/UNIX/v2man/man5/core core(V)])

	One big question concerns details of how the process' address space was laid out - the man pages for ld(III) and exec(II) simply say nothing at all. With the KS11, one can assume it started at 0 - but who knows? Without the KS11, it must have started at a higher address (since on the PDP-11, [[interrupt vector]]s are in low memory), as on [[MINI-UNIX#Implementation_details\|MINI-UNIX]]; but again, neither V1's ld(III) nor exec(II) mentions this detail. One could work it out from the V1 [[kernel]] source, if one is ''really'' interested...		One big question concerns details of how the process' address space was laid out - the man pages for ld(III) and exec(II) simply say nothing at all. With the KS11, one can assume it started at 0 - but who knows? Without the KS11, it must have started at a higher address (since on the PDP-11, [[interrupt vector]]s are in low memory), as on [[MINI-UNIX#Implementation_details\|MINI-UNIX]]; but again, neither V1's ld(III) nor exec(II) mentions this detail. One could work it out from the V1 [[kernel]] source, if one is ''really'' interested...
Line 18:		Line 18:
	Some also had [[KE11-A Extended Arithmetic Element]]s. (It's important to remember that not all the machines running UNIX would have had their hardware updated simultaneously: e.g. the patent group's -11/20 would not have needed the KS11 as much, since it was running mature [[application]]s. So V2 UNIX was probably conditionalized to run with and without the KS11. V1 used the KE11-A, and was not conditionalized to be able to run without it, though.)		Some also had [[KE11-A Extended Arithmetic Element]]s. (It's important to remember that not all the machines running UNIX would have had their hardware updated simultaneously: e.g. the patent group's -11/20 would not have needed the KS11 as much, since it was running mature [[application]]s. So V2 UNIX was probably conditionalized to run with and without the KS11. V1 used the KE11-A, and was not conditionalized to be able to run without it, though.)

	The -11/45 was apparently expected in the near future; V2 seems to have started looking forward to it - "a trap is simulated by the [[floating point]] simulator" ([http://squoze.net/UNIX/v2man/man5/core core(V)]); "if they correspond to 11/45 floating point [[instruction]]s" ([http://squoze.net/UNIX/v2man/man3/fptrap fptrap[III]). It is possible that they already had the -11/45 at this point, but one would tend to doubt it: "immediate mode ((pc)+) is not supported, since the PDP-11/45 handbook is not clear on what to do about it." (If they had it, a simple experiment would have produced the answer.) And "Double precision results are probably less correct than the hardware will be" (note tense). (All from fptrap[III].)		The -11/45 was apparently expected in the near future; V2 seems to have started looking forward to it - "a trap is simulated by the [[floating point]] simulator" ([http://squoze.net/UNIX/v2man/man5/core core(V)]); "if they correspond to 11/45 floating point [[instruction]]s". ([http://squoze.net/UNIX/v2man/man3/fptrap fptrap(III)]) It is possible that they already had the -11/45 at this point, but one would tend to doubt it: "immediate mode ((pc)+) is not supported, since the PDP-11/45 handbook is not clear on what to do about it." (If they had it, a simple experiment would have produced the answer.) And "Double precision results are probably less correct than the hardware will be" (note tense). (All from fptrap(III).)

	The [[file system]] is almost identical to the [[UNIX file system\|V6 one]]; the only major differences are that i) the free blocks are stored as a bit [[array]], rather than a linked [[list]], and ii) [[peripheral\|device]] 'special files' are indicated by [[inode]] numbers below 41. (not via a flag in the 'mode' word in the inode, as later).		The [[file system]] is almost identical to the [[UNIX file system\|V6 one]]; the only major differences are that i) the free blocks are stored as a bit [[array]], rather than a linked [[list]], and ii) [[peripheral\|device]] 'special files' are indicated by [[inode]] numbers below 41. (not via a flag in the 'mode' word in the inode, as later).
Line 26:		Line 26:
	A copy of Second Edition does not seem to be extant. [[The Unix Heritage Society\|TUHS]] claims to have the [[source code]] for some of its user code: an early version of the first [[C programming language\|C]] [[compiler]] (C was just being defined at the point in time), and many commands (but see below). The 'UNIX Programmer's Manual: Second Edition' is also available.		A copy of Second Edition does not seem to be extant. [[The Unix Heritage Society\|TUHS]] claims to have the [[source code]] for some of its user code: an early version of the first [[C programming language\|C]] [[compiler]] (C was just being defined at the point in time), and many commands (but see below). The 'UNIX Programmer's Manual: Second Edition' is also available.

	The 'cmd' directory at TUHS actually seems to be for [[UNIX Third Edition\|V3]] (see discussion there). However, the sources for some V2 commands were reconstructed by [[decompilation\|decompiling]] the [[object code]] for some that were located in an old dump (in the 's2-bits.tar.gz' file in the TUHS archive, below). ~~They~~ seem to be a mixture of 'naked' binaries, ~~along~~ with some in V1 and V2 [[UNIX a.out file\|a.out		The 'cmd' directory at TUHS actually seems to be for [[UNIX Third Edition\|V3]] (see discussion there). However, the sources for some V2 commands were reconstructed by [[decompilation\|decompiling]] the [[object code]] for some that were located in an old dump (in the 's2-bits.tar.gz' file in the TUHS archive, below). The binaries seem to be a mixture of 'naked' binaries, with some in V1 and V2 [[UNIX a.out file\|a.out formats]].
	formats]].

	==External links==		==External links==

Jnc: Add my archaeology

2023-10-18T17:03:28Z

Add my archaeology

← Older revision		Revision as of 17:03, 18 October 2023
Line 10:		Line 10:
	}}		}}

	'''UNIX Second Edition''' (often referred to as '''UNIX V2''' or '''V2 UNIX''' - 'Unix' was still normally given in all capital letters at this point in time) was an early version of [[UNIX]]. There were 10 instances of UNIX running inside Bell at this point.		'''UNIX Second Edition''' (often referred to as '''UNIX V2''' or '''V2 UNIX''' - 'Unix' was still normally given in all capital letters at this point in time) was an early version of [[UNIX]]. There were 10 instances of UNIX running inside Bell at this point. It still ran on the [[PDP-11/20]] model of the PDP-11.

	~~It still ran on~~ the [[PDP-11/20]] ~~model of~~ the PDP-11~~; the~~ [[~~PDP~~-11/45]] ~~was apparently expected in the near future~~. Some of the -11/20's running UNIX had a [[KS11 ~~Memory Protection and Relocation option]] to provide [[memory management]] (~~"the current system, which has relocation and protection hardware"([http://squoze.net/UNIX/v2man/man5/core core(V)])). Some also had [[KE11-A Extended Arithmetic Element]]s.		Support for protection (and relocation - i.e. memory that looks, to user code, as if it's at 0, but is actually at, say, 060000 in physical terms) in PDP-11 UNIX ''pre-dates'' the [[PDP-11/45]] (the first PDP-11 model on which it was a standard). [[Digital Equipment Corporation\|DEC]] had a rare, and now almost forgotten "Memory Protect & Relocate" [[memory management]] option for the -11/20, the [[KS11 Memory Protection and Relocation option\|KS11]]. Some of the -11/20's running V2 UNIX had a KS11 - "the current system, which has relocation and protection hardware" ([http://squoze.net/UNIX/v2man/man5/core core(V)]).

			One big question concerns details of how the process' address space was laid out - the man pages for ld(III) and exec(II) simply say nothing at all. With the KS11, one can assume it started at 0 - but who knows? Without the KS11, it must have started at a higher address (since on the PDP-11, [[interrupt vector]]s are in low memory), as on [[MINI-UNIX#Implementation_details\|MINI-UNIX]]; but again, neither V1's ld(III) nor exec(II) mentions this detail. One could work it out from the V1 [[kernel]] source, if one is ''really'' interested...

			Some also had [[KE11-A Extended Arithmetic Element]]s. (It's important to remember that not all the machines running UNIX would have had their hardware updated simultaneously: e.g. the patent group's -11/20 would not have needed the KS11 as much, since it was running mature [[application]]s. So V2 UNIX was probably conditionalized to run with and without the KS11. V1 used the KE11-A, and was not conditionalized to be able to run without it, though.)

			The -11/45 was apparently expected in the near future; V2 seems to have started looking forward to it - "a trap is simulated by the [[floating point]] simulator" ([http://squoze.net/UNIX/v2man/man5/core core(V)]); "if they correspond to 11/45 floating point [[instruction]]s" ([http://squoze.net/UNIX/v2man/man3/fptrap fptrap[III]). It is possible that they already had the -11/45 at this point, but one would tend to doubt it: "immediate mode ((pc)+) is not supported, since the PDP-11/45 handbook is not clear on what to do about it." (If they had it, a simple experiment would have produced the answer.) And "Double precision results are probably less correct than the hardware will be" (note tense). (All from fptrap[III].)

	The [[file system]] is almost identical to the [[UNIX file system\|V6 one]]; the only major differences are that i) the free blocks are stored as a bit [[array]], rather than a linked [[list]], and ii) [[peripheral\|device]] 'special files' are indicated by [[inode]] numbers below 41. (not via a flag in the 'mode' word in the inode, as later).		The [[file system]] is almost identical to the [[UNIX file system\|V6 one]]; the only major differences are that i) the free blocks are stored as a bit [[array]], rather than a linked [[list]], and ii) [[peripheral\|device]] 'special files' are indicated by [[inode]] numbers below 41. (not via a flag in the 'mode' word in the inode, as later).

Jnc: Add Matthew Gilmore's archaeology on V2 commands

2023-10-18T16:19:09Z

Add Matthew Gilmore's archaeology on V2 commands

← Older revision		Revision as of 16:19, 18 October 2023
Line 16:		Line 16:
	The [[file system]] is almost identical to the [[UNIX file system\|V6 one]]; the only major differences are that i) the free blocks are stored as a bit [[array]], rather than a linked [[list]], and ii) [[peripheral\|device]] 'special files' are indicated by [[inode]] numbers below 41. (not via a flag in the 'mode' word in the inode, as later).		The [[file system]] is almost identical to the [[UNIX file system\|V6 one]]; the only major differences are that i) the free blocks are stored as a bit [[array]], rather than a linked [[list]], and ii) [[peripheral\|device]] 'special files' are indicated by [[inode]] numbers below 41. (not via a flag in the 'mode' word in the inode, as later).

	A copy of Second Edition does not seem to be extant. [[The Unix Heritage Society\|TUHS]] ~~has~~ the [[source code]] for some of its user code: an early version of the first [[C programming language\|C]] [[compiler]] (C was just being defined at the point in time), and many commands. The 'UNIX Programmer's Manual: Second Edition' is also available.		==Source==

			A copy of Second Edition does not seem to be extant. [[The Unix Heritage Society\|TUHS]] claims to have the [[source code]] for some of its user code: an early version of the first [[C programming language\|C]] [[compiler]] (C was just being defined at the point in time), and many commands (but see below). The 'UNIX Programmer's Manual: Second Edition' is also available.

			The 'cmd' directory at TUHS actually seems to be for [[UNIX Third Edition\|V3]] (see discussion there). However, the sources for some V2 commands were reconstructed by [[decompilation\|decompiling]] the [[object code]] for some that were located in an old dump (in the 's2-bits.tar.gz' file in the TUHS archive, below). They seem to be a mixture of 'naked' binaries, along with some in V1 and V2 [[UNIX a.out file\|a.out
			formats]].

	==External links==		==External links==

	* [https://minnie.tuhs.org/cgi-bin/utree.pl?file=V2 V2] - file tree at TUHS		* [https://minnie.tuhs.org/cgi-bin/utree.pl?file=V2 V2] - file tree at TUHS
			** [https://minnie.tuhs.org/cgi-bin/utree.pl?file=V2/cmd cmd] - not really
			* [https://www.tuhs.org/Archive/Distributions/Research/1972_stuff 1972 stuff] - the source for the above
			** [https://www.tuhs.org/Archive/Distributions/Research/1972_stuff/Readme Readme] - a discussion of what's there
			* [https://minnie.tuhs.org/mailman3/hyperkitty/list/tuhs@tuhs.org/thread/Y5CHHVMQY3JUOKI4PD7OVB4FBD4ILV2O/ S2-bits V2 Source Code Restoration]
			* [https://gitlab.com/segaloco/v2src v2src]
	* [http://squoze.net/UNIX/v2man/ UNIX Programmer's Manual: Second Edition]		* [http://squoze.net/UNIX/v2man/ UNIX Programmer's Manual: Second Edition]
	** [http://squoze.net/UNIX/v2man/man0 Introduction]		** [http://squoze.net/UNIX/v2man/man0 Introduction]

Jnc: V2 could use the KS11

2023-05-17T22:43:35Z

V2 could use the KS11

← Older revision		Revision as of 22:43, 17 May 2023
Line 12:		Line 12:
	'''UNIX Second Edition''' (often referred to as '''UNIX V2''' or '''V2 UNIX''' - 'Unix' was still normally given in all capital letters at this point in time) was an early version of [[UNIX]]. There were 10 instances of UNIX running inside Bell at this point.		'''UNIX Second Edition''' (often referred to as '''UNIX V2''' or '''V2 UNIX''' - 'Unix' was still normally given in all capital letters at this point in time) was an early version of [[UNIX]]. There were 10 instances of UNIX running inside Bell at this point.

	It still ran on the [[PDP-11/20]] model of the PDP-11; the [[PDP-11/45]] was apparently expected in the near future. The [[file system]] is almost identical to the [[UNIX file system\|V6 one]]; the only major differences are that i) the free blocks are stored as a bit [[array]], rather than a [[list]], and ii) [[peripheral\|device]] 'special files' are indicated by [[inode]] numbers below 41. (not via a flag in the 'mode' word in the inode, as later).		It still ran on the [[PDP-11/20]] model of the PDP-11; the [[PDP-11/45]] was apparently expected in the near future. Some of the -11/20's running UNIX had a [[KS11 Memory Protection and Relocation option]] to provide [[memory management]] ("the current system, which has relocation and protection hardware"([http://squoze.net/UNIX/v2man/man5/core core(V)])). Some also had [[KE11-A Extended Arithmetic Element]]s.

			The [[file system]] is almost identical to the [[UNIX file system\|V6 one]]; the only major differences are that i) the free blocks are stored as a bit [[array]], rather than a linked [[list]], and ii) [[peripheral\|device]] 'special files' are indicated by [[inode]] numbers below 41. (not via a flag in the 'mode' word in the inode, as later).

	A copy of Second Edition does not seem to be extant. [[The Unix Heritage Society\|TUHS]] has the [[source code]] for some of its user code: an early version of the first [[C programming language\|C]] [[compiler]] (C was just being defined at the point in time), and many commands. The 'UNIX Programmer's Manual: Second Edition' is also available.		A copy of Second Edition does not seem to be extant. [[The Unix Heritage Society\|TUHS]] has the [[source code]] for some of its user code: an early version of the first [[C programming language\|C]] [[compiler]] (C was just being defined at the point in time), and many commands. The 'UNIX Programmer's Manual: Second Edition' is also available.

Jnc: +previous version

2022-06-23T04:19:42Z

+previous version

← Older revision		Revision as of 04:19, 23 June 2022
Line 3:		Line 3:
	\| creator = AT&T/[[Western Electric]]		\| creator = AT&T/[[Western Electric]]
	\| year introduced = June, 1972		\| year introduced = June, 1972
	\| next version = [[UNIX Third Edition]]		\| previous version = [[UNIX First Edition\|V1]]
			\| current version = V2
			\| next version = [[UNIX Third Edition\|V3]]
	\| type = [[Multi-tasking]], [[multi-user]]		\| type = [[Multi-tasking]], [[multi-user]]
	\| architecture = [[PDP-11 architecture\|PDP-11]]		\| architecture = [[PDP-11 architecture\|PDP-11]]
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	It still ran on the [[PDP-11/20]] model of the PDP-11; the [[PDP-11/45]] was apparently expected in the near future. The [[file system]] is almost identical to the [[UNIX file system\|V6 one]]; the only major differences are that i) the free blocks are stored as a bit [[array]], rather than a [[list]], and ii) [[peripheral\|device]] 'special files' are indicated by [[inode]] numbers below 41. (not via a flag in the 'mode' word in the inode, as later).		It still ran on the [[PDP-11/20]] model of the PDP-11; the [[PDP-11/45]] was apparently expected in the near future. The [[file system]] is almost identical to the [[UNIX file system\|V6 one]]; the only major differences are that i) the free blocks are stored as a bit [[array]], rather than a [[list]], and ii) [[peripheral\|device]] 'special files' are indicated by [[inode]] numbers below 41. (not via a flag in the 'mode' word in the inode, as later).

	A copy of Second Edition does not seem to be extant. [[The Unix Heritage Society\|TUHS]] has the [[source code]] for some of its user code: an early version of the first [[C programming language\|C]] [[compiler]] (C was just being defined at the point in time), and many commands. The '~~NIX~~ Programmer's Manual: Second Edition' is also available.		A copy of Second Edition does not seem to be extant. [[The Unix Heritage Society\|TUHS]] has the [[source code]] for some of its user code: an early version of the first [[C programming language\|C]] [[compiler]] (C was just being defined at the point in time), and many commands. The 'UNIX Programmer's Manual: Second Edition' is also available.

	==External links==		==External links==

	* [https://minnie.tuhs.org/cgi-bin/utree.pl?file=V2 V2]		* [https://minnie.tuhs.org/cgi-bin/utree.pl?file=V2 V2] - file tree at TUHS
	* [http://squoze.net/UNIX/v2man/ UNIX Programmer's Manual: Second Edition]		* [http://squoze.net/UNIX/v2man/ UNIX Programmer's Manual: Second Edition]
	** [http://squoze.net/UNIX/v2man/man0 Introduction]		** [http://squoze.net/UNIX/v2man/man0 Introduction]

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	\| creator = AT&T/[[Western Electric]]		\| creator = AT&T/[[Western Electric]]
	\| year introduced = June, 1972		\| year introduced = June, 1972
			\| next version = [[UNIX Third Edition]]
	\| type = [[Multi-tasking]], [[multi-user]]		\| type = [[Multi-tasking]], [[multi-user]]
	\| architecture = [[PDP-11 architecture\|PDP-11]]		\| architecture = [[PDP-11 architecture\|PDP-11]]

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Fills the gap

New page

{{Infobox OS
| name = Unix V2
| creator = AT&T/[[Western Electric]]
| year introduced = June, 1972
| type = [[Multi-tasking]], [[multi-user]]
| architecture = [[PDP-11 architecture|PDP-11]]
}}

'''UNIX Second Edition''' (often referred to as '''UNIX V2''' or '''V2 UNIX''' - 'Unix' was still normally given in all capital letters at this point in time) was an early version of [[UNIX]]. There were 10 instances of UNIX running inside Bell at this point.

It still ran on the [[PDP-11/20]] model of the PDP-11; the [[PDP-11/45]] was apparently expected in the near future. The [[file system]] is almost identical to the [[UNIX file system|V6 one]]; the only major differences are that i) the free blocks are stored as a bit [[array]], rather than a [[list]], and ii) [[peripheral|device]] 'special files' are indicated by [[inode]] numbers below 41. (not via a flag in the 'mode' word in the inode, as later).

A copy of Second Edition does not seem to be extant. [[The Unix Heritage Society|TUHS]] has the [[source code]] for some of its user code: an early version of the first [[C programming language|C]] [[compiler]] (C was just being defined at the point in time), and many commands. The 'NIX Programmer's Manual: Second Edition' is also available.

==External links==

* [https://minnie.tuhs.org/cgi-bin/utree.pl?file=V2 V2]
* [http://squoze.net/UNIX/v2man/ UNIX Programmer's Manual: Second Edition]
** [http://squoze.net/UNIX/v2man/man0 Introduction]
** [http://squoze.net/UNIX/v2man/man5/fs File system]
** [http://squoze.net/UNIX/v2man/man7/bproc Boot procedures]
** [http://squoze.net/UNIX/v2man/man7/init init - process control initialization]

{{Nav Unix}}

[[Category: PDP-11 Operating Systems]]
[[Category: Non-DEC Operating Systems]]
[[Category: Unix OS's]]