From 788cf51a9546dd1daddf9f550af84c6bbecc94dc Mon Sep 17 00:00:00 2001 From: Thomas Schwinge Date: Thu, 5 Mar 2009 19:20:56 +0100 Subject: community/gsoc/project_ideas: Split into subpages. --- community/gsoc/project_ideas/tmpfs.mdwn | 44 +++++++++++++++++++++++++++++++++ 1 file changed, 44 insertions(+) create mode 100644 community/gsoc/project_ideas/tmpfs.mdwn (limited to 'community/gsoc/project_ideas/tmpfs.mdwn') diff --git a/community/gsoc/project_ideas/tmpfs.mdwn b/community/gsoc/project_ideas/tmpfs.mdwn new file mode 100644 index 00000000..7c9cf67b --- /dev/null +++ b/community/gsoc/project_ideas/tmpfs.mdwn @@ -0,0 +1,44 @@ +[[meta copyright="Copyright © 2008, 2009 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="Fix tmpfs"]] + +In some situations it is desirable to have a file system that is not backed by +actual disk storage, but only by anonymous memory, i.e. lives in the RAM (and +possibly swap space). + +A simplistic way to implement such a memory filesystem is literally creating a +ramdisk, i.e. simply allocating a big chunck of RAM (called a memory store in +Hurd terminology), and create a normal filesystem like ext2 on that. However, +this is not very efficient, and not very convenient either (the filesystem +needs to be recreated each time the ramdisk is invoked). A nicer solution is +having a real [[hurd/translator/tmpfs]], which creates all filesystem +structures directly in RAM, allocating memory on demand. + +The Hurd has had such a tmpfs for a long time. However, the existing +implementation doesn't work anymore -- it got broken by changes in other parts +of the Hurd design. + +There are several issues. The most serious known problem seems to be that for +technical reasons it receives [[microkernel/mach/RPC]]s from two different +sources on one [[microkernel/mach/port]], and gets mixed up with them. Fixing +this is non-trivial, and requires a good understanding of the involved +mechanisms. + +The goal of this project to get a fully working, full featured tmpfs +implementation. It requires digging into some parts of the Hurd, incuding the +[[pager_interface|hurd/libpager]] and [[hurd/translator]] programming. This +task probably doesn't require any design work, only good debugging skills. + +Possible mentors: ? + +Exercise: Take a go at one of the existing issues in tmpfs. You may not be able +to finish this in the limited amount of time, but you should at least be able +to do a detailed analysis of the problem. -- cgit v1.2.3