diff options
| -rw-r--r-- | faq/which_microkernel.mdwn | 15 | ||||
| -rw-r--r-- | history.mdwn | 10 | ||||
| -rw-r--r-- | history/port_to_another_microkernel.mdwn | 171 | ||||
| -rw-r--r-- | history/port_to_another_microkernel/discussion.mdwn (renamed from hurd/faq/which_microkernel.mdwn) | 45 | ||||
| -rw-r--r-- | history/port_to_l4.mdwn | 105 | ||||
| -rw-r--r-- | hurd-l4.mdwn | 8 | ||||
| -rw-r--r-- | hurd.mdwn | 8 | ||||
| -rw-r--r-- | hurd/ng.mdwn | 2 | ||||
| -rw-r--r-- | microkernel/coyotos.mdwn | 7 | ||||
| -rw-r--r-- | microkernel/l4.mdwn | 5 |
10 files changed, 213 insertions, 163 deletions
diff --git a/faq/which_microkernel.mdwn b/faq/which_microkernel.mdwn new file mode 100644 index 00000000..608e6b3f --- /dev/null +++ b/faq/which_microkernel.mdwn @@ -0,0 +1,15 @@ +[[!meta copyright="Copyright © 2009, 2011 Free Software Foundation, Inc."]] + +[[!meta license="""[[!toggle id="license" text="GFDL 1.2+"]][[!toggleable +id="license" text="Permission is granted to copy, distribute and/or modify this +document under the terms of the GNU Free Documentation License, Version 1.2 or +any later version published by the Free Software Foundation; with no Invariant +Sections, no Front-Cover Texts, and no Back-Cover Texts. A copy of the license +is included in the section entitled [[GNU Free Documentation +License|/fdl]]."]]"""]] + +[[!meta title="What happened with the ports to the L4 / Coyotos / Viengoos +microkernels?"]] + +This story is told on the page about the +[[history/port_to_another_microkernel]]. diff --git a/history.mdwn b/history.mdwn index 8f155b54..0abcbd52 100644 --- a/history.mdwn +++ b/history.mdwn @@ -1,13 +1,13 @@ -[[!meta copyright="Copyright © 1998, 1999, 2001, 2002, 2007, 2008, 2009 Free -Software Foundation, Inc."]] +[[!meta copyright="Copyright © 1998, 1999, 2001, 2002, 2007, 2008, 2009, 2011 +Free Software Foundation, Inc."]] [[!meta license="""[[!toggle id="license" text="GFDL 1.2+"]][[!toggleable id="license" text="Permission is granted to copy, distribute and/or modify this document under the terms of the GNU Free Documentation License, Version 1.2 or any later version published by the Free Software Foundation; with no Invariant Sections, no Front-Cover Texts, and no Back-Cover Texts. A copy of the license -is included in the section entitled -[[GNU Free Documentation License|/fdl]]."]]"""]] +is included in the section entitled [[GNU Free Documentation +License|/fdl]]."]]"""]] [[!tag stable_URL]] @@ -91,4 +91,4 @@ mailing lists. --- - * [[Port_to_L4]] + * [[Port_to_another_microkernel]] diff --git a/history/port_to_another_microkernel.mdwn b/history/port_to_another_microkernel.mdwn new file mode 100644 index 00000000..b347cf38 --- /dev/null +++ b/history/port_to_another_microkernel.mdwn @@ -0,0 +1,171 @@ +[[!meta copyright="Copyright © 2001, 2002, 2003, 2004, 2005, 2006, 2007, 2008, +2009, 2010, 2011 Free Software Foundation, Inc."]] + +[[!meta license="""[[!toggle id="license" text="GFDL 1.2+"]][[!toggleable +id="license" text="Permission is granted to copy, distribute and/or modify this +document under the terms of the GNU Free Documentation License, Version 1.2 or +any later version published by the Free Software Foundation; with no Invariant +Sections, no Front-Cover Texts, and no Back-Cover Texts. A copy of the license +is included in the section entitled [[GNU Free Documentation +License|/fdl]]."]]"""]] + +[[!meta title="Porting the Hurd to another microkernel"]] + +At first, there was an effort to port the Hurd from the [[Mach +microkernel|microkernel/mach]] to the [[L4_microkernel_family|microkernel/l4]]. +Then the story continued... + +[[!toc levels=2]] + + +# L4 + +## Initial Idea + +Encountering a number of fundamental design issues with the [[Mach +microkernel|microkernel/mach]] (mostly regarding [[resource +management|open_issues/resource_management_problems]]), some of the Hurd +developers began experimenting with using other microkernels for the Hurd +around the turn of the millenium. + +The idea of using L4 as a [[microkernel]] for a Hurd system was initially +voiced in the [[community]] by Okuji Yoshinori, who, for discussing this +purpose, created the [[mailing_lists/l4-hurd]] mailing list in November 2000. + +Over the years, a lot of discussion have been held on this mailing list, which +today is still the right place for [[next-generation Hurd|hurd/ng]] +discussions. + + +## Why? + +Even though that said resource management issues constitute a broad research +topic, there was no hope that the original Mach project would work on these: +[[microkernel/Mach]] wasn't maintained by its original authors anymore. Mach +had served its purpose as a research vehicle, and has been retired by its +stakeholders. + +Thus, switching to a well-maintained current [[microkernel]] was expected to +yield a more solid foundation for a Hurd system than the [[decaying +Mach|microkernel/mach/history]] design and implementation was able to. + +At that time, the [[L4 microkernel family|microkernel/L4]] was one obvious +choice. Being a second-generation microkernel, it was deemed to provide for a +faster system kernel implementation, especially in the time-critical [[IPC]] +paths. Also, as L4 was already implemented for a bunch of different +architectures (x86, Alpha, MIPS; also including SMP support), and the Hurd +itself being rather archtecture-agnostic, it was expected to be able to easily +support more platforms than with the existing system. + + +## Steps and Goals + +At the same time, the idea was -- while mucking with the system's core anyway +-- to improve on some fundamental design issues, too -- like the resource +management problems, for example. + +One goal of porting the Hurd to L4 was to make the Hurd independent of +[[microkernel/Mach]] interfaces, to make it somewhat microkernel-agnostic. + +One idea was to first introduce a Mach-on-L4 emulation layer, to easily get a +usable (though slow) Hurd-using-Mach-interfaces-on-L4 system, and then +gradually move the Hurd servers to use L4 intefaces rather than Mach ones. + +A design upon the lean L4 kernel would finally have made it feasible to move +devices drivers out of the kernel's [[TCB]]. + + +# Implementation + +The project itself then was mostly lead by Marcus Brinkmann and Neal Walfield. +Neal started the original Hurd/L4 port while visiting Karlsruhe university in +2002. He explains: + +> My intention was to adapt the Hurd to exploit L4's concepts and intended +> [[design_pattern]]s; it was not to simply provide a Mach +> [[compatibility_layer]] on top of L4. When I left Karlsruhe, I no longer had +> access to [[microkernel/l4/Pistachio]] as I was unwilling to sign an NDA. +> Although the specification was available, the Karlsruhe group only [released +> their code in May +> 2003](https://lists.ira.uni-karlsruhe.de/pipermail/l4ka/2003-May/000345.html). +> Around this time, Marcus began hacking on Pistachio. He created a relatively +> complete run-time. I didn't really become involved again until the second +> half of 2004, after I complete by Bachelors degree. + +Development of Hurd/L4 was done in the [CVS module +`hurd-l4`](http://savannah.gnu.org/cgi-bin/viewcvs/hurd/hurd-l4/). The `doc` +directory contains a design document that is worth reading for anyone who +wishes to learn more about Hurd/L4. + +Even though there was progress -- see, for example, the [[QEMU image for +L4|hurd/running/qemu/image_for_l4]] -- this port never reached a releasable +state. Simple POSIX programs, such as `banner` could run, but for more complex +system interfaces, a lot more work was needed. + +Eventually, a straight-forward port of the original Hurd's design wasn't deemed +feasible anymore by the developers, partly due to them not cosidering L4 +suitable for implementing a general-purpose operating system on top of it, and +because of deficiencies in the original Hurd's design, which they discovered +along their way. Neal goes on: + +> Before Marcus and I considered [[microkernel/Coyotos]], we had already +> rejected some parts of the Hurd's design. The +> [[open_issues/resource_management_problems]] were +> what prompted me to look at L4. Also, some of the problems with +> [[hurd/translator]]s were already well-known to us. (For a more detailed +> description of the problems we have identified, see our [[hurd/critique]] in the +> 2007 July's SIGOPS OSR. We have also written a forward-looking +> [[hurd/ng/position_paper]].) + +> We visited Jonathan Shapiro at Hopkins in January 2006. This resulted in a +> number of discussions, some quite influential, and not always in a way which +> aligned our position with that of Jonathan's. This was particularly true of +> a number of security issues. + +A lange number of discussion threads can be found in the archives of the +[[mailing_lists/l4-hurd]] mailing list. + +> Hurd-NG, as we originally called it, was an attempt to articulate the system +> that we had come to envision in terms of interfaces and description of the +> system's structure. The new name was selected, if I recall correctly, as it +> clearly wasn't the Hurd nor the Hurd based on L4. + + +## Termination + +As of 2005, development of Hurd/L4 has stopped. + + +# Coyotos + +Following that, an attempt was started to use the kernel of the +[[microkernel/Coyotos]] system. As Coyotos is an object capability system +througout, the microkernel would obviously be more suitable for this purpose; +and it looked pretty promising in the beginning. However, further +investigations found that there are some very fundamental philosophical +differences between the Coyotos and Hurd designs; and thus this this attempt +was also abandonned, around 2006 / 2007. (This time before producing any +actual code.) + + +# Viengoos + +By now (that is, after 2006), there were some new [[microkernel/L4]] variants +available, which added protected [[IPC]] paths and other features necessary for +object capability systems; so it might be possible to implement the Hurd on top +of these. However, by that time the developers concluded that microkernel +design and system design are interconnected in very intricate ways, and thus +trying to use a third-party microkernel will always result in trouble. So Neal +Walfield created the experimental [[microkernel/Viengoos]] kernel instead -- +based on the experience from the previous experiments with L4 and Coyotos -- +for his [[research on resource +management|open_issues/resource_management_problems]]. Currently he works in +another research area though, and thus Viengoos is on hold. + + +# Intermediate Results + +Note that while none of the microkernel work is active now, the previous +experiments already yielded a lot of experience, which will be very useful in +the further development / improvement of the mainline (Mach-based) Hurd +implementation. diff --git a/hurd/faq/which_microkernel.mdwn b/history/port_to_another_microkernel/discussion.mdwn index f6225188..f2161195 100644 --- a/hurd/faq/which_microkernel.mdwn +++ b/history/port_to_another_microkernel/discussion.mdwn @@ -8,49 +8,6 @@ Sections, no Front-Cover Texts, and no Back-Cover Texts. A copy of the license is included in the section entitled [[GNU Free Documentation License|/fdl]]."]]"""]] -[[!meta title="What happened to the L4 / Coyotos / Viengoos microkernels?"]] - -Encountering a number of fundamental design issues with the Mach microkernel -(mostly with resource management), -some of the Hurd developers began experimenting with using other microkernels for the Hurd. - -The first attempt was reimplementing the Hurd on the L4 (Pistachio) microkernel. -This got going around 2003/2004, -and got pretty far (running some simple POSIX programs, such as "banner"); -however over time some lingering design issues turned out to be fundamental problems: -the original L4 is not suitable for building object capability systems like the Hurd. -Thus development was aborted in 2005. - -Following that, an attempt was started to use the kernel of the Coyotos system. -As Coyotos is an object-capability system througout, -the microkernel would obviously be more suitable for this purpose; -and it looked pretty promising in the beginning. -However, further investigations found -that there are some very fundamental philosophical differences -between the Coyotos and Hurd designs; -and thus this this attempt was also abandonned, around 2006/2007. -(This time before producing any actual code.) - -By now there were some new L4 variants available, -which added protected IPC paths and other features necessary for object capability systems; -so it might be possible to implement the Hurd on top of these. -However, by that time the developers concluded that microkernel design and system design -are interconnected in very intricate ways, -and thus trying to use a third-party microkernel will always result in trouble. -So Neal Walfield created the experimental [[Viengoos|microkernel/viengoos]] kernel instead -- -based on the experience from the previous experiments with L4 and Coyotos -- -for his research on resource management. -Currently he works in another research area though, and thus Viengoos is on hold. - -Note that while none of the microkernel work is active now, -the previous experiments already yielded a lot of experience, -which will be very useful in the further development/improvement -of the mainline (Mach-based) Hurd implementation. - -<!-- - ---- - IRC, #hurd, 2011-01-12. [[!taglink open_issue_documentation]] @@ -110,5 +67,3 @@ IRC, #hurd, 2011-01-12. <antrik> manpower is not something that comes from nowhere. again, having something working is crucial in a volunteer project like this <antrik> there are no fixed plans - ---> diff --git a/history/port_to_l4.mdwn b/history/port_to_l4.mdwn index b58c0d91..3f951a64 100644 --- a/history/port_to_l4.mdwn +++ b/history/port_to_l4.mdwn @@ -1,108 +1,13 @@ -[[!meta copyright="Copyright © 2001, 2002, 2003, 2004, 2005, 2006, 2007, 2008, -2009, 2010 Free Software Foundation, Inc."]] +[[!meta copyright="Copyright © 2011 Free Software Foundation, Inc."]] [[!meta license="""[[!toggle id="license" text="GFDL 1.2+"]][[!toggleable id="license" text="Permission is granted to copy, distribute and/or modify this document under the terms of the GNU Free Documentation License, Version 1.2 or any later version published by the Free Software Foundation; with no Invariant Sections, no Front-Cover Texts, and no Back-Cover Texts. A copy of the license -is included in the section entitled -[[GNU Free Documentation License|/fdl]]."]]"""]] +is included in the section entitled [[GNU Free Documentation +License|/fdl]]."]]"""]] -[[!meta title="Porting the Hurd to L4: Hurd/L4"]] +[[!tag stable_URL]] -There was an effort to port the Hurd from [[microkernel/Mach]] to the -[[L4_microkernel_family|microkernel/L4]]. - -The idea of using L4 as a [[microkernel]] for a [[Hurd_system|hurd]] was -initially voiced in the [[Hurd_community|community]] by Okuji Yoshinori, who, -for discussing this purpose, created the [[mailing lists/l4-hurd]] mailing list -in November 2000. - -The project itself then was mostly lead by Marcus Brinkmann and Neal Walfield. -Even though there was progress -- see, for example, the -[[QEMU image for L4|hurd/running/qemu/image for l4]] -- this port never reached a -releasable state. Eventually, a straight-forward port of the original Hurd's -design wasn't deemed feasible anymore by the developers, partly due to them not -cosidering L4 suitable for implementing a general-purpose operating system on -top of it, and because of deficiencies in the original Hurd's design, which -they discovered along their way. Read the [[hurd/critique]] and a -[[hurd/ng/position paper]]. - -By now, the development of Hurd/L4 has stopped. However, Neal Walfield moved -on to working on a newly designed kernel called [[microkernel/viengoos]]. - -Over the years, a lot of discussion have been held on the -[[mailing lists/l4-hurd]] mailing list, which today is still the right place -for [[next-generation Hurd|hurd/ng]] discussions. - -Development of Hurd/L4 was done in the `hurd-l4` module of the Hurd CVS -repository. The `doc` directory contains a design document that is worth -reading for anyone who wishes to learn more about Hurd/L4. - - -One goal of porting the Hurd to L4 was to make the Hurd independend of Mach -interfaces, to make it somewhat microkernel-agnostic. - -Mach wasn't maintained by its original authors anymore, so switching to a -well-maintained current [[microkernel]] was expected to yield a more solid -foundation for a Hurd system than the decaying Mach design and implementation -was able to. - -L4 being a second-generation [[microkernel]] was deemed to provide for a faster -system kernel implementation, especially in the time-critical [[IPC]] paths. -Also, as L4 was already implemented for a bunch of different architectures -(IA32, Alpha, MIPS; SMP), and the Hurd itself being rather archtecture-unaware, -it was expected to be able to easily support more platforms than with the -existing system. - -A design upon the lean L4 kernel would finally have moved devices drivers out -of the kernel's [[TCB]]. - - -One idea was to first introduce a Mach-on-L4 emulation layer, to easily get a -usable (though slow) Hurd-using-Mach-interfaces-on-L4 system, and then -gradually move the Hurd servers to use L4 intefaces rather than Mach ones. - - -Neal Walfield started the original Hurd/L4 port while at Karlsruhe in 2002. He -explains: - -> My intention was to adapt the Hurd to exploit L4's concepts and intended -> [[design_pattern]]s; it was not to simply provide a Mach -> [[compatibility_layer]] on top of L4. When I left Karlsruhe, I no longer had -> access to [[microkernel/l4/Pistachio]] as I was unwilling to sign an NDA. -> Although the specification was available, the Karlsruhe group only [released -> their code in May -> 2003](https://lists.ira.uni-karlsruhe.de/pipermail/l4ka/2003-May/000345.html). -> Around this time, Marcus began hacking on Pistachio. He created a relatively -> complete run-time. I didn't really become involved again until the second -> half of 2004, after I complete by Bachelors degree. - -> Before Marcus and I considered [[microkernel/Coyotos]], we had already -> rejected some parts of the Hurd's design. The -> [[open issues/resource management problems]] were -> what prompted me to look at L4. Also, some of the problems with -> [[hurd/translator]]s were already well-known to us. (For a more detailed -> description of the problems we have identified, see our [[hurd/critique]] in the -> 2007 July's SIGOPS OSR. We have also written a forward-looking -> [[hurd/ng/position paper]].) - -> We visited Jonathan Shapiro at Hopkins in January 2006. This resulted in a -> number of discussions, some quite influential, and not always in a way which -> aligned our position with that of Jonathan's. This was particularly true of -> a number of security issues. - -A lange number of discussion threads can be found in the archives of the -[[mailing lists/l4-hurd]] mailing list. - -> Hurd-NG, as we originally called it, was an attempt to articulate the system -> that we had come to envision in terms of interfaces and description of the -> system's structure. The new name was selected, if I recall correctly, as it -> clearly wasn't the Hurd nor the Hurd based on L4. - - -The source code is still available in [CVS module -`hurd-l4`](http://savannah.gnu.org/cgi-bin/viewcvs/hurd/hurd-l4/) (note that -this repository has in the beginning also been used for Neal's -[[microkernel/Viengoos]]). +[[!meta redir=port_to_another_microkernel]] diff --git a/hurd-l4.mdwn b/hurd-l4.mdwn index 579c1190..afc8f8f3 100644 --- a/hurd-l4.mdwn +++ b/hurd-l4.mdwn @@ -1,13 +1,13 @@ -[[!meta copyright="Copyright © 2009 Free Software Foundation, Inc."]] +[[!meta copyright="Copyright © 2009, 2011 Free Software Foundation, Inc."]] [[!meta license="""[[!toggle id="license" text="GFDL 1.2+"]][[!toggleable id="license" text="Permission is granted to copy, distribute and/or modify this document under the terms of the GNU Free Documentation License, Version 1.2 or any later version published by the Free Software Foundation; with no Invariant Sections, no Front-Cover Texts, and no Back-Cover Texts. A copy of the license -is included in the section entitled -[[GNU Free Documentation License|/fdl]]."]]"""]] +is included in the section entitled [[GNU Free Documentation +License|/fdl]]."]]"""]] [[!tag stable_URL]] -[[!meta redir=history/port_to_l4]] +[[!meta redir=history/port_to_another_microkernel]] @@ -1,13 +1,13 @@ [[!meta copyright="Copyright © 2001, 2002, 2003, 2004, 2005, 2006, 2007, 2008, -2009, 2010 Free Software Foundation, Inc."]] +2009, 2010, 2011 Free Software Foundation, Inc."]] [[!meta license="""[[!toggle id="license" text="GFDL 1.2+"]][[!toggleable id="license" text="Permission is granted to copy, distribute and/or modify this document under the terms of the GNU Free Documentation License, Version 1.2 or any later version published by the Free Software Foundation; with no Invariant Sections, no Front-Cover Texts, and no Back-Cover Texts. A copy of the license -is included in the section entitled -[[GNU Free Documentation License|/fdl]]."]]"""]] +is included in the section entitled [[GNU Free Documentation +License|/fdl]]."]]"""]] The GNU Hurd is under active development. Because of that, there is no *stable* version. We distribute the Hurd sources only through [[Git|source_repositories]] at present. @@ -31,7 +31,7 @@ in the *unstable* branch of the Debian archive. * [[What_Is_the_GNU_Hurd]] - A Brief Description * [[Advantages]]. And [[challenges]]. * [[History]] - * [[history/Port_to_L4]] + * [[history/Port_to_another_microkernel]] * [[Logo]] * [[Status]] * [[KnownHurdLimits]] diff --git a/hurd/ng.mdwn b/hurd/ng.mdwn index de33949d..481386a4 100644 --- a/hurd/ng.mdwn +++ b/hurd/ng.mdwn @@ -13,7 +13,7 @@ This section explains the motivations behind the new design: * [[Issues_with_L4_Pistachio]] * [[Limitations_of_the_original_Hurd_design]] - * History of the [[history/port_to_L4]] + * History of the [[history/port_to_another_microkernel]] # Work already done diff --git a/microkernel/coyotos.mdwn b/microkernel/coyotos.mdwn index 5ecea688..fec023ba 100644 --- a/microkernel/coyotos.mdwn +++ b/microkernel/coyotos.mdwn @@ -1,5 +1,5 @@ -[[!meta copyright="Copyright © 2006, 2007, 2008, 2010 Free Software Foundation, -Inc."]] +[[!meta copyright="Copyright © 2006, 2007, 2008, 2010, 2011 Free Software +Foundation, Inc."]] [[!meta license="""[[!toggle id="license" text="GFDL 1.2+"]][[!toggleable id="license" text="Permission is granted to copy, distribute and/or modify this @@ -28,3 +28,6 @@ design. The coyotos microkernel specification can be found [here](http://www.coyotos.org/docs/ukernel/spec.html). + +There once was the idea of a GNU/Hurd [[port using the Coyotos +microkernel|history/port_to_another_microkernel]], but this didn't come live. diff --git a/microkernel/l4.mdwn b/microkernel/l4.mdwn index 45929842..7af5e6fc 100644 --- a/microkernel/l4.mdwn +++ b/microkernel/l4.mdwn @@ -1,4 +1,4 @@ -[[!meta copyright="Copyright © 2004, 2006, 2007, 2008, 2010 Free Software +[[!meta copyright="Copyright © 2004, 2006, 2007, 2008, 2010, 2011 Free Software Foundation, Inc."]] [[!meta license="""[[!toggle id="license" text="GFDL 1.2+"]][[!toggleable @@ -20,7 +20,8 @@ on formally verifying an L4 microkernel. * {{$sel4}} -There was a GNU/Hurd [[history/port_to_L4]], which is now stalled. +There was a GNU/Hurd [[port to L4|history/port_to_another_microkernel]], which +is now stalled. [[!ymlfront data=""" |