Computer History Wiki - User contributions [en]

UNIX Fourth Edition

2025-12-20T04:15:34Z

Aap: refer to v4 installation instructions

{{Infobox OS
| name = Unix V4
| creator = AT&T/[[Western Electric]]
| year introduced = November, 1973
| previous version = [[UNIX Third Edition|V3]]
| current version = V4
| next version = [[UNIX Fifth Edition|V5]]
| type = [[Multi-tasking]], [[multi-user]]
| architecture = [[PDP-11 architecture|PDP-11]]
}}

'''UNIX Fourth Edition''' (often referred to as '''UNIX V4''' or '''V4 UNIX''' - 'Unix' was still normally given in all capital letters at this point in time) was an important early version of [[UNIX]]. It was the first version in which the [[kernel]] was written in [[C programming language|C]]. It also had minor changes to the [[UNIX file system‎]] (such as the ability of any [[inode]] to hold a [[peripheral|device]] 'special file'), which left it in the form it retained until the [[BSD Fast File System]].

Apparently, the only model of PDP-11 supported was the [[PDP-11/45]].

A complete copy of Fourth Edition does not seem to be extant. [[The Unix Heritage Society|TUHS]] has a copy of the 'UNIX Programmer's Manual' and the [[source]] for what would become the V4 kernel. The main differences in this 'nsys' kernel compared to the later V4 kernel are the earlier V3 way of registering signal handlers, and a few not yet implemented system calls. Most importantly [[pipe]]s had not yet been implemented, making this kernel not fully functional even on a V3 system.

==Possible Source(s)==

"A tape-based piece of unique Unix history may have been lying quietly in storage at the University of Utah for 50+ years. The question is whether researchers will be able to take this piece of middle-aged media and rewind it back to the 1970s to get the data off."

* [https://www.theregister.com/2025/11/07/unix_fourth_edition_tape_rediscovered/ UNIX fourth edition tape rediscovered]

"– The 4th Edition (November 1973 — Research-V4) contains only source markup
for the manual pages: 18975 lines of troff code."

Research UNIX v4, dated to 1973:
https://www.spinellis.gr/pubs/jrnl/2016-EMPSE-unix-history/html/unix-history.pdf

=== Installing and Running V4 ===

Since the tape has been read, the system can now be installed and booted.
After follow the installation instructions here: http://squoze.net/UNIX/v4
booting the system looks like this:

<pre>
% pdp11 boot.ini

[...]
; boot from RK0, now in uboot
k
unix

login: root
# ls
bin
dev
etc
lib
mnt
tmp
unix
usr
#
</pre>

==External links==

* [https://minnie.tuhs.org/cgi-bin/utree.pl?file=V4 V4]
** [https://minnie.tuhs.org/cgi-bin/utree.pl?file=V4/nsys nsys] - complete kernel source
*** [https://minnie.tuhs.org/cgi-bin/utree.pl?file=V4/nsys/ken/11-45 11-45] - possibly physical layout of the UNIX group's PDP-11/45
*** [https://minnie.tuhs.org/cgi-bin/utree.pl?file=V4/nsys/ken/low.s low.s] - possibly configuration of the UNIX group's PDP-11/45
** [https://minnie.tuhs.org/cgi-bin/utree.pl?file=V4/man/man0/intro UNIX Programmer's Manual Fourth Edition - Introduction]
** [https://minnie.tuhs.org/cgi-bin/utree.pl?file=V4/man/man5/fs.5 File system]
* [http://squoze.net/UNIX/v4man/ UNIX Programmer's Manual: Fourth Edition]

====News====

* [https://news.ycombinator.com/item?id=45840321 Ycombinator]
* [https://discuss.systems/@ricci/115504720054699983 Discuss.systems]
** "We have arranged to deliver it to the Computer History Museum."
<blockquote>I have the equipment. It is a 3M tape so it will probably be fine.
It will be digitized on my analog recovery set up and I'll use Len Shustek's readtape program to recover the data.
The only issue right now is my workflow isn't a "while you wait" thing, so I need to pull all the pieces into one physical location and test everything before I tell Penny it's OK to come out.

The whole process is test the condition on a tape retensioner. I'm hoping I don't have to bake it, since that takes a day, then digitize it, shuttle the 10s of gigabytes of samples to another machine to decode it. I want to skip the shuttle step and get the analyzer running on the digitizer. -bitsavers.org</blockquote>

{{Nav Unix}}

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

UNIX Fourth Edition

2025-12-20T03:07:20Z

Aap: wrong link

{{Infobox OS
| name = Unix V4
| creator = AT&T/[[Western Electric]]
| year introduced = November, 1973
| previous version = [[UNIX Third Edition|V3]]
| current version = V4
| next version = [[UNIX Fifth Edition|V5]]
| type = [[Multi-tasking]], [[multi-user]]
| architecture = [[PDP-11 architecture|PDP-11]]
}}

'''UNIX Fourth Edition''' (often referred to as '''UNIX V4''' or '''V4 UNIX''' - 'Unix' was still normally given in all capital letters at this point in time) was an important early version of [[UNIX]]. It was the first version in which the [[kernel]] was written in [[C programming language|C]]. It also had minor changes to the [[UNIX file system‎]] (such as the ability of any [[inode]] to hold a [[peripheral|device]] 'special file'), which left it in the form it retained until the [[BSD Fast File System]].

Apparently, the only model of PDP-11 supported was the [[PDP-11/45]].

A complete copy of Fourth Edition does not seem to be extant. [[The Unix Heritage Society|TUHS]] has a copy of the 'UNIX Programmer's Manual' and the [[source]] for what would become the V4 kernel. The main differences in this 'nsys' kernel compared to the later V4 kernel are the earlier V3 way of registering signal handlers, and a few not yet implemented system calls. Most importantly [[pipe]]s had not yet been implemented, making this kernel not fully functional even on a V3 system.

==Possible Source(s)==

"A tape-based piece of unique Unix history may have been lying quietly in storage at the University of Utah for 50+ years. The question is whether researchers will be able to take this piece of middle-aged media and rewind it back to the 1970s to get the data off."

* [https://www.theregister.com/2025/11/07/unix_fourth_edition_tape_rediscovered/ UNIX fourth edition tape rediscovered]

"– The 4th Edition (November 1973 — Research-V4) contains only source markup
for the manual pages: 18975 lines of troff code."

Research UNIX v4, dated to 1973:
https://www.spinellis.gr/pubs/jrnl/2016-EMPSE-unix-history/html/unix-history.pdf

=== Booting v4 ===

Since the tape has been read, the system can now be booted.
Get the required files (unix_v4.tap and disk.rk) here: http://squoze.net/UNIX/v4

With the following boot.ini
<pre>
set cpu 11/45
att rk0 disk.rk
att tm0 unix_v4.tap
boot -o tm
</pre>

you can start the system like this:
<pre>
% pdp11 boot.ini

[...]

=uboot
k
unix

login: root
# ls
bin
dev
etc
lib
mnt
tmp
unix
usr
#
</pre>

==External links==

* [https://minnie.tuhs.org/cgi-bin/utree.pl?file=V4 V4]
** [https://minnie.tuhs.org/cgi-bin/utree.pl?file=V4/nsys nsys] - complete kernel source
*** [https://minnie.tuhs.org/cgi-bin/utree.pl?file=V4/nsys/ken/11-45 11-45] - possibly physical layout of the UNIX group's PDP-11/45
*** [https://minnie.tuhs.org/cgi-bin/utree.pl?file=V4/nsys/ken/low.s low.s] - possibly configuration of the UNIX group's PDP-11/45
** [https://minnie.tuhs.org/cgi-bin/utree.pl?file=V4/man/man0/intro UNIX Programmer's Manual Fourth Edition - Introduction]
** [https://minnie.tuhs.org/cgi-bin/utree.pl?file=V4/man/man5/fs.5 File system]
* [http://squoze.net/UNIX/v4man/ UNIX Programmer's Manual: Fourth Edition]

====News====

* [https://news.ycombinator.com/item?id=45840321 Ycombinator]
* [https://discuss.systems/@ricci/115504720054699983 Discuss.systems]
** "We have arranged to deliver it to the Computer History Museum."
<blockquote>I have the equipment. It is a 3M tape so it will probably be fine.
It will be digitized on my analog recovery set up and I'll use Len Shustek's readtape program to recover the data.
The only issue right now is my workflow isn't a "while you wait" thing, so I need to pull all the pieces into one physical location and test everything before I tell Penny it's OK to come out.

The whole process is test the condition on a tape retensioner. I'm hoping I don't have to bake it, since that takes a day, then digitize it, shuttle the 10s of gigabytes of samples to another machine to decode it. I want to skip the shuttle step and get the analyzer running on the digitizer. -bitsavers.org</blockquote>

{{Nav Unix}}

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

UNIX Fourth Edition

2025-12-20T03:06:56Z

Aap: Added quick note about booting the v4 tape

{{Infobox OS
| name = Unix V4
| creator = AT&T/[[Western Electric]]
| year introduced = November, 1973
| previous version = [[UNIX Third Edition|V3]]
| current version = V4
| next version = [[UNIX Fifth Edition|V5]]
| type = [[Multi-tasking]], [[multi-user]]
| architecture = [[PDP-11 architecture|PDP-11]]
}}

'''UNIX Fourth Edition''' (often referred to as '''UNIX V4''' or '''V4 UNIX''' - 'Unix' was still normally given in all capital letters at this point in time) was an important early version of [[UNIX]]. It was the first version in which the [[kernel]] was written in [[C programming language|C]]. It also had minor changes to the [[UNIX file system‎]] (such as the ability of any [[inode]] to hold a [[peripheral|device]] 'special file'), which left it in the form it retained until the [[BSD Fast File System]].

Apparently, the only model of PDP-11 supported was the [[PDP-11/45]].

A complete copy of Fourth Edition does not seem to be extant. [[The Unix Heritage Society|TUHS]] has a copy of the 'UNIX Programmer's Manual' and the [[source]] for what would become the V4 kernel. The main differences in this 'nsys' kernel compared to the later V4 kernel are the earlier V3 way of registering signal handlers, and a few not yet implemented system calls. Most importantly [[pipe]]s had not yet been implemented, making this kernel not fully functional even on a V3 system.

==Possible Source(s)==

"A tape-based piece of unique Unix history may have been lying quietly in storage at the University of Utah for 50+ years. The question is whether researchers will be able to take this piece of middle-aged media and rewind it back to the 1970s to get the data off."

* [https://www.theregister.com/2025/11/07/unix_fourth_edition_tape_rediscovered/ UNIX fourth edition tape rediscovered]

"– The 4th Edition (November 1973 — Research-V4) contains only source markup
for the manual pages: 18975 lines of troff code."

Research UNIX v4, dated to 1973:
https://www.spinellis.gr/pubs/jrnl/2016-EMPSE-unix-history/html/unix-history.pdf

=== Booting v4 ===

Since the tape has been read, the system can now be booted.
Get the required files (unix_v4.tap and disk.rk) here: http://squoze.net/UNIX/v4/README

With the following boot.ini
<pre>
set cpu 11/45
att rk0 disk.rk
att tm0 unix_v4.tap
boot -o tm
</pre>

you can start the system like this:
<pre>
% pdp11 boot.ini

[...]

=uboot
k
unix

login: root
# ls
bin
dev
etc
lib
mnt
tmp
unix
usr
#
</pre>

==External links==

* [https://minnie.tuhs.org/cgi-bin/utree.pl?file=V4 V4]
** [https://minnie.tuhs.org/cgi-bin/utree.pl?file=V4/nsys nsys] - complete kernel source
*** [https://minnie.tuhs.org/cgi-bin/utree.pl?file=V4/nsys/ken/11-45 11-45] - possibly physical layout of the UNIX group's PDP-11/45
*** [https://minnie.tuhs.org/cgi-bin/utree.pl?file=V4/nsys/ken/low.s low.s] - possibly configuration of the UNIX group's PDP-11/45
** [https://minnie.tuhs.org/cgi-bin/utree.pl?file=V4/man/man0/intro UNIX Programmer's Manual Fourth Edition - Introduction]
** [https://minnie.tuhs.org/cgi-bin/utree.pl?file=V4/man/man5/fs.5 File system]
* [http://squoze.net/UNIX/v4man/ UNIX Programmer's Manual: Fourth Edition]

====News====

* [https://news.ycombinator.com/item?id=45840321 Ycombinator]
* [https://discuss.systems/@ricci/115504720054699983 Discuss.systems]
** "We have arranged to deliver it to the Computer History Museum."
<blockquote>I have the equipment. It is a 3M tape so it will probably be fine.
It will be digitized on my analog recovery set up and I'll use Len Shustek's readtape program to recover the data.
The only issue right now is my workflow isn't a "while you wait" thing, so I need to pull all the pieces into one physical location and test everything before I tell Penny it's OK to come out.

The whole process is test the condition on a tape retensioner. I'm hoping I don't have to bake it, since that takes a day, then digitize it, shuttle the 10s of gigabytes of samples to another machine to decode it. I want to skip the shuttle step and get the analyzer running on the digitizer. -bitsavers.org</blockquote>

{{Nav Unix}}

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

TX-0

2023-07-19T06:56:00Z

Aap:

The '''TX-0''' was a [[transistor]] computer (reportedly the first ever built), at the MIT Lincoln laboratory. Predecessor to the [[TX-2]] and an influence on the [[PDP-1]] design. It was in some sense a successor to the [[Memory Test Computer]], itself a spin-off of the pioneering [[Whirlwind]].

{{semi-stub}}

==Registers==

These are the registers in the original design. Later updates changed some register widths and added registers.

{| class="wikitable"
! Name || Size (bits) || Meaning
|-
| AC || 18 || Accumulator
|-
| MBR || 18 || Memory buffer register
|-
| MAR || 16 || Memory address register
|-
| PC || 16 || Program counter
|-
| IR || 2 || Instruction register
|-
| LR || 18 || Live register
|-
| TBR || 18 || Toggle switch buffer register
|-
| TAC || 18 || Toggle switch accumulator
|}

==Test mode==

The console has a switch to set '''test mode''' in which operations are taken from the TBR. The operations are similar to regular instructions, but with a different interpretation:

{| class="wikitable"
! TBR 0-1 || Instruction || Meaning
|-
| 00 || STO ''x'' || Store TAC in memory location ''x''.
|-
| 01 || ADD ''x'' || Add memory location ''x'' to AC. (Check MBR to examine.)
|-
| 10 || TRN ''x'' || Change to '''normal mode''' and start running at location ''x''.
|-
| 11 || OPR ''x'' || Execute the instruction.
|}

==External links==

* [http://bitsavers.org/pdf/mit/tx-0/ TX-0] - documents at [[Bitsavers]]
* [https://dspace.mit.edu/bitstream/handle/1721.1/4132/RLE-TR-627-42827671.pdf RLE-TR-627 TX-0 Computer History]
* [https://www.computerhistory.org/pdp-1/2e1b209cb40237b91228cdf26a60e3f8/ MIT TX-0 Computer]
* C. Gordon Bell, Gerald Butler, Robert Gray, John E. Mcnamara, Donald Vonada, and Ronald Wilson, [http://gordonbell.azurewebsites.net/Computer_Engineering/00000146.htm The PDP-1 and Other 18-Bit Computers], in C. Gordon Bell, J. Craig Mudge, John. E. McNamara, ''Computer Engineering: A DEC View of Hardware Systems Design'', Digital Press, Bedford, 1978 - Some material on the TX-0, and also covers its descendants (including the [[PDP-1]])
* [https://www.digibarn.com/stories/linc/documents/LINC-Personal-Workstation/LINC-Personal-Workstation.pdf The LINC Was Early and Small] - lengthy personal memoir by Wesley Clark; it also covers the TX-0

[[Category: Computers]]
[[Category: 18-bit Computers]]

UNIX Fourth Edition

2022-05-27T09:51:56Z

Aap: Some more info on the nsys kernel.

{{Infobox OS
| name = Unix V4
| creator = AT&T/[[Western Electric]]
| year introduced = November, 1973
| next version = [[UNIX Fifth Edition]]
| type = [[Multi-tasking]], [[multi-user]]
| architecture = [[PDP-11 architecture|PDP-11]]
}}

'''UNIX Fourth Edition''' (often referred to as '''UNIX V4''' or '''V4 UNIX''' - 'Unix' was still normally given in all capital letters at this point in time) was an important early version of [[UNIX]]. It was the first version in which the [[kernel]] was written in [[C programming language|C]]. It also had minor changes to the [[UNIX file system‎]] (such as the ability of any [[inode]] to hold a [[peripheral|device]] 'special file'), which left it in the form it retained until the [[BSD Fast File System]].

Apparently, the only model of PDP-11 supported was the [[PDP-11/45]].

A complete copy of Fourth Edition does not seem to be extant. [[The Unix Heritage Society|TUHS]] has a copy of the 'UNIX Programmer's Manual'
and the [[source]] for what would become the V4 kernel.
The main differences in this nsys kernel compared to the later V4 kernel are the earlier V3 way of registering signal handlers
and a few not yet implemented system calls. Most importantly pipes had not yet been implemented, making this kernel not fully functional even on a V3 system.

==External links==

* [https://minnie.tuhs.org/cgi-bin/utree.pl?file=V4 V4]
** [https://minnie.tuhs.org/cgi-bin/utree.pl?file=V4/nsys nsys] - complete kernel source
** [https://minnie.tuhs.org/cgi-bin/utree.pl?file=V4/man/man0/intro UNIX Programmer's Manual Fourth Edition - Introduction]
** [https://minnie.tuhs.org/cgi-bin/utree.pl?file=V4/man/man5/fs.5 File system]
* [http://squoze.net/UNIX/v4man/ UNIX Programmer's Manual: Fourth Edition]

{{Nav Unix}}

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

UNIX First Edition

2022-05-24T21:43:44Z

Aap: added link to manual

{{Infobox OS
| image = v1unix.png
| caption = Logging into a Unix version 1 box
| name = Unix v1
| creator = Western Electric, AT&T
| current version = SYSVr4 - Solais 10 (2009)
| year introduced = 1972
| type = Multitasking, multiuser
| architecture = [[PDP-7]], [[PDP-11]] theoretically portable
}}

[[UNIX]]'s first edition has been restored by the work of Warren Toomey, Tim Newsham and others. The current project homepage is located [http://code.google.com/p/unix-jun72/ here].

== PDP-7 predecessor ==

The earlier first version was written in [[assembly language]] for a spare [[PDP-7]] in Bell Labs. Originally what started out as a game (spacelander) eventually UNIX started to fill a need for typesetting on 'cheap' [[minicomputer]]s.

The first version was primarly written in assembler.

== Restoration project ==

On December 2008, the project made its first relase using scanned printouts as source material, a team was able to re-enter the source files, and using apout they were able to construct a system using various bits from later Unix versions into a booting system for SIMH's PDP-11 emulator.

== How do I get this to run?! ==

There is a packaged version that will easily install on Windows machines that can be downloaded [http://sourceforge.net/project/downloading.php?group_id=204974&filename=Research-unixv1-0.3.exe&a=25520957 here]

You can find all the pieces for this below:

The current binary build can be downloaded from the [http://unix-jun72.googlecode.com/ google code] page [http://unix-jun72.googlecode.com/files/images-20080625.tgz here].

You need a version of [[SIMH]] 3.8-1 or higher, as they will incorporate certain changes required for v1 unix.

== What Runs? ==

Not very much!

==External links==

* [https://www.tuhs.org/Archive/Distributions/Research/Dennis_v1/ 1st Edition UNIX]
** [https://www.tuhs.org/Archive/Distributions/Research/Dennis_v1/PreliminaryUnixImplementationDocument_Jun72.pdf UNIX Implementation Document] - contains scans of a complete listing
** [https://www.tuhs.org/Archive/Distributions/Research/Dennis_v1/1stEdman.html Unix Programmer's Manual First Edition] - overview
* [http://squoze.net/UNIX/v1man/ UNIX Programmer's Manual]

{{Nav Unix}}

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

UNIX Third Edition

2022-05-24T21:42:27Z

Aap: added link to manual

{{Infobox OS
| name = Unix V3
| creator = AT&T/[[Western Electric]]
| year introduced = February, 1973
| type = [[Multi-tasking]], [[multi-user]]
| architecture = [[PDP-11 architecture|PDP-11]]
}}

'''UNIX Third Edition''' (often referred to as '''UNIX V3''' or '''V3 UNIX''' - 'Unix' was still normally given in all capital letters at this point in time) was a significant early version of [[UNIX]]. It was the version in which [[pipe]]s appeared, and the last version in which the [[kernel]] was written in [[assembly language]].

It still ran on the [[PDP-11/20]] model of the PDP-11, as well as the [[PDP-11/45]] (apparently). 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 complete copy of Third Edition does not seem to be extant. [[The Unix Heritage Society|TUHS]] has a copy of the 'UNIX Programmer's Manual Third Edition', and the [[source code]] for an early version of the first [[C programming language|C]] [[compiler]] (C was just being defined at the point in time, although it first appeared in [[UNIX Second Edition]]).

==External links==

* [https://minnie.tuhs.org/cgi-bin/utree.pl?file=V3 V3]
** [https://minnie.tuhs.org/cgi-bin/utree.pl?file=V3/man/man0/intro UNIX Programmer's Manual Third Edition - Introduction]
*** [https://minnie.tuhs.org/cgi-bin/utree.pl?file=V3/man/man5/fs.5 File system]
*** [https://minnie.tuhs.org/cgi-bin/utree.pl?file=V3/man/manx/obproc.7 Boot procedures] - possibly obsolete?
* [http://squoze.net/UNIX/v3man/ UNIX Programmer's manual]

{{Nav Unix}}

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

UNIX Fourth Edition

2022-05-24T21:41:33Z

Aap: added link to manual

{{Infobox OS
| name = Unix V4
| creator = AT&T/[[Western Electric]]
| year introduced = November, 1973
| type = [[Multi-tasking]], [[multi-user]]
| architecture = [[PDP-11 architecture|PDP-11]]
}}

'''UNIX Fourth Edition''' (often referred to as '''UNIX V4''' or '''V4 UNIX''' - 'Unix' was still normally given in all capital letters at this point in time) was an important early version of [[UNIX]]. It was the first version in which the [[kernel]] was written in [[C programming language|C]]. It also had minor changes to the [[UNIX file system‎]] (such as the ability of any [[inode]] to hold a [[peripheral|device]] 'special file'), which left it in the form it retained until the [[BSD Fast File System]].

Apparently, the only model of PDP-11 supported was the [[PDP-11/45]].

A complete copy of Fourth Edition does not seem to be extant. [[The Unix Heritage Society|TUHS]] has the [[source]] for what appears to be a shortly pre-V4 kernel, and a copy of the 'UNIX Programmer's Manual'.

==External links==

* [https://minnie.tuhs.org/cgi-bin/utree.pl?file=V4 V4]
** [https://minnie.tuhs.org/cgi-bin/utree.pl?file=V4/nsys nsys] - complete kernel source
*** [https://minnie.tuhs.org/cgi-bin/utree.pl?file=V4/man/man0/intro UNIX Programmer's Manual Fourth Edition - Introduction]
*** [https://minnie.tuhs.org/cgi-bin/utree.pl?file=V4/man/man5/fs.5 File system]
* [http://squoze.net/UNIX/v4man/ UNIX Programmer's Manual]

{{Nav Unix}}

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

UNIX Sixth Edition

2022-05-24T21:39:59Z

Aap: added link to manual

{{Infobox OS
| image = v6unix.png
| caption = Logging into a V6 UNIX system
| name = Unix V6
| creator = AT&T/[[Western Electric]]
| current version = V6
| year introduced = May 1975
| type = [[Multi-tasking]], [[multi-user]]
| architecture = [[PDP-11 architecture|PDP-11]]
}}

'''UNIX Sixth Edition''' (often referred to as '''UNIX V6''' or '''V6 UNIX''' - 'Unix' was still normally given in all capital letters at this point in time) was one of the most influential early versions of [[UNIX]]. It was the first version which was widely distributed outside Bell Labs, appearing as it did shortly after the influential CACM article on Unix, and it had an ''enormous'' impact.

It was also the base for many important branches of UNIX, including [[PWB/UNIX]] and the [[BSD]] Unix family (it was in fact the first version of Unix to have more than one descendant). It was also one of the more popular Research versions from Bell Labs, along with [[Unix Seventh Edition]].

To many computer scientists encountering it for the first time in its era, it had the feel of a then [[mainframe]] [[operating system]], but on a [[minicomputer]]; it felt totally unlike all the other minicomputer OS's at the time. Many also still consider it to have been the system with the highest ratio of power to size, ever.

As distributed from Bell Labs, it ran only on [[PDP-11]]s, although outside Bell Labs it was later ported to several other architectures (see below).

It was very similar to the earlier [[UNIX Fifth Edition]]; the main change was the support of so-called [[PDP-11 Memory Management|split I+D space]], both in the [[kernel]], and for [[user]] [[process]]es. It also supported the [[PDP-11/70]] with more than 256 Kilobytes of [[main memory]], and the resultant [[UNIBUS map]].

UNIX V6 included even more documentation than V5, which included gems like [[Programming in C - A Tutorial]].

==Other Platforms==

In addition to the [[PDP-11]], which was the only machine the original Bell Laboratories distribution of V6 ran on, it was later ported to several other architectures.

=== Interdata 8/32 ===

The first port of Unix to another architecture was performed outside of Bell Laboratories; V6 was ported to an [[Interdata 7/32]] at the University of Wollongong. This was also the first port to a 32 bit platform, although Bell completed their own port to the very similar [[Interdata 8/32]] shortly thereafter (that port later became [[Unix Seventh Edition]]).

=== Intel 80286 ===

There is a port by Szigeti Szabolcs to the [[i286|Intel 80286]] CPU, available in [http://www.tuhs.org/archive_sites.html the Unix Archive] under Other/V6on286. It requires a copy of [[MS-DOS]] to run.

=== i386 ===

There is a 32bit re-write to the [[Intel 80386|x86 cpu]], an instructional operating system called 'XV6', used at MIT for an operating systems [http://pdos.csail.mit.edu/6.828/2006/index.html class]. You can download the [http://pdos.csail.mit.edu/6.828/2006/src/xv6-rev0.tar.gz source].

== Folk Lore ==

[[Image:Lions UNIX book cover.jpg|thumb|150px|right|The Lions Book]]

V6 Unix is also famous because of the "[[Lions book]]". [[John Lions]] at the University of New South Wales wrote up an excellent dissection of the UNIX kernel, and taught it in his OS classes.

Unfortunately, the book ran into intellectual property issues with Bell, so its formal distribution was halted; however, it became ''the'' guide to UNIX internals as it was photo-copied over and over, in a Western equivalent to the ''samizdat'' of the old USSR.

Recently, with the open release of older versions of UNIX, the intellectual property issues were cleared, and the Lions book is now finally publicly available.

== Games ==

The game situation didn't improve that much from V5 to V6.
<pre>
bj
chess
cubic
moo
ttt
wump
</pre>

==Running UNIX V6==

To install and run UNIX V6, one needs a distribution (either an image of a distribution tape, or images of [[disk]]s), and either an emulator, or an actual PDP-11 or Interdata.

V6 ''can'' be run on a [[PDP-11/23]], but it takes a few [[Running UNIX V6 on an -11/23|minor mods]] to do so.

===Distros===

There are two different distribution sets for V6 in the [[TUHS]] archive: 'Dennis_v6' and 'Ken_Wellsch_v6' (below). The contents page says:

<pre>
Dennis_v6
---------
v6root.gz, v6src.gz and v6doc.gz are a set of three RK05 images of Sixth
Edition with root, /usr and documentation, from Dennis Ritchie.

Ken_Wellsch_v6
--------------
v6.tape.gz is a copy of the Sixth Edition distribution tape which was sent
in by Ken Wellsch.</pre>

It notes that there are differences between the two, but hadn't investigated what they are. Here are some details: the source files for the kernel are identical, except for sys/ken/main.c, which has the following added in the Wellsch version:

<pre> printf("RESTRICTED RIGHTS\n\n");
printf("Use, duplication or disclosure is subject to\n");
printf("restrictions stated in Contract with Western\n");
printf("Electric Company, Inc.\n");</pre>

(What clearly happened is that after they'd done some distribution,
the AT+T lawyers made them add that.) Anyway, as a result, the binary system images 'rkunix', etc are slightly different between the two.

Everything else seems to be identical: everything in /bin, /etc, /lib, /usr/bin and /usr/lib are all identical.

===SIMH===

One possibility for an emulator is to use [[SIMH]]; you can get V6 by looking for uv6swre.zip and iu6swre.zip, PDP-11 and Interdata versions respectively.

*http://simh.trailing-edge.com/kits/uv6swre.zip
*http://simh.trailing-edge.com/kits/iu6swre.zip

There is also a great lecture series involving SIMH and v6 which can be found here:
*[http://wwwlehre.dhbw-stuttgart.de/~helbig/os/index.html http://wwwlehre.dhbw-stuttgart.de/~helbig/os/index.html]
*[[xv6 homework 4]]
*[[xv6 homework 5]]
*[[xv6 homework 6]]
*[[xv6 homework 7]]
*[[xv6 homework 8]]

===Ersatz-11===

Another choice for an emulator is [[Ersatz-11]]; complete instructions for how to bring up V6 under Ersatz-11 are available, as well as instructions for how to make a more usable V6 under Ersatz-11: see the link below.

==See also==

* [[UNIX V6 internals]]
* [[UNIX V6 kernel memory layout]]
** [[UNIX V6 dump analysis]]
* [[Installing UNIX Sixth Edition]]
** [[Setting up UNIX Sixth Edition]]
** [[Upgrading UNIX Sixth Edition]]
** [[Running UNIX V6 on an -11/23]]
* [[Installing UNIX v6 (PDP-11) on SIMH]]
** [[Running UNIX v6 in SIMH]]
* [[Installing UNIX Sixth Edition on Ersatz-11]]

==External links==

* [https://www.tuhs.org/Archive/Distributions/Research/Dennis_v6/ Ritchie distro]
* [https://www.tuhs.org/Archive/Distributions/Research/Ken_Wellsch_v6/ Wellsch distro]
* [http://squoze.net/UNIX/v6man/ UNIX Programmer's manual]

{{Nav Unix}}

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

UNIX Fifth Edition

2022-05-24T21:38:24Z

Aap: date was v6, not v5. added link to manual

This was the first research version to leave [[Bell Labs]] to the world outside AT&T.

{{Infobox OS
| image = v5unix.jpg
| caption = Logging into a v5 unix system
| name = Unix v5
| creator = AT&T/Western Electric
| current version = v5
| year introduced = June, 1974
| type = Multitasking, multiuser
| architecture = [[PDP-11]]
}}

== Platforms ==

The only known platform for Unix v5 was the [[PDP-11]], with support for both the [[PDP-11/40]] and [[PDP-11/45]].

== How do I get this to run?! ==

Well you'll need a [[disk]] image, and an [[emulator]] or a PDP-11... I'd recommend [[SIMH]] and you can get v5 by looking for v5root.gz .. There is also the guide [[Running Unix v5 in SIMH]].

=== Games ===

While limited, there is a few games on the v5 distro:

<pre>
bj
chess
cubic
moo
ttt
wump
</pre>

{{semi-stub}}

==External links==

* [https://minnie.tuhs.org/cgi-bin/utree.pl?file=V5 V5]
* [http://squoze.net/UNIX/v5man/ UNIX Programmer's manual]

{{Nav Unix}}

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

UNIX Fifth Edition

2022-05-24T14:20:31Z

Aap: mch.s has a .45 switch. I haven't tested 11/40 support, but the code looks fine

This was one of the more popular research versions to leave Bell Labs.

{{Infobox OS
| image = v5unix.jpg
| caption = Logging into a v5 unix system
| name = Unix v5
| creator = AT&T/Western Electric
| current version = v5
| year introduced = 1973
| type = Multitasking, multiuser
| architecture = [[PDP-11]]
}}

== Platforms ==

The only known platform for Unix v5 was the [[PDP-11]] with support for both the [[PDP-11/40]] and [[PDP-11/45]].

== How do I get this to run?! ==

Well you'll need a [[disk]] image, and an [[emulator]] or a PDP-11... I'd recommend [[SIMH]] and you can get v5 by looking for v5root.gz .. There is also the guide [[Running Unix v5 in SIMH]].

=== Games ===

While limited, there is a few games on the v5 distro:

<pre>
bj
chess
cubic
moo
ttt
wump
</pre>

{{semi-stub}}

{{Nav Unix}}

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

UNIX Fifth Edition

2022-05-24T13:59:20Z

Aap: Removed wrong into about pipes. They first appeared in v3.

This was one of the more popular research versions to leave Bell Labs.

{{Infobox OS
| image = v5unix.jpg
| caption = Logging into a v5 unix system
| name = Unix v5
| creator = AT&T/Western Electric
| current version = v5
| year introduced = 1973
| type = Multitasking, multiuser
| architecture = [[PDP-11]]
}}

== Platforms ==

Thee only known platform for Unix v5 was the [[PDP-11]], and primarly only the [[PDP-11/45]].

== How do I get this to run?! ==

Well you'll need a [[disk]] image, and an [[emulator]] or a PDP-11... I'd recommend [[SIMH]] and you can get v5 by looking for v5root.gz .. There is also the guide [[Running Unix v5 in SIMH]].

=== Games ===

While limited, there is a few games on the v5 distro:

<pre>
bj
chess
cubic
moo
ttt
wump
</pre>

{{semi-stub}}

{{Nav Unix}}

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