This page is a place to keep track of ideas about things that may be improved in GNU Mach, so that it'll evolve to a reliable microkernel for The Hurd, both in terms of stability and performance. If you find anything missing here, please feel free to add a entry with a short description.

If you want to help with any of the task (thanks!), please send a mail to bug-hurd stating what task you wish to work on, so that no duplicate efforts end up.

Active Branches

gnumach-1-branch is the main branch.
gnumach-1-branch-Xen-branch is a branch created by Samuel Thibault for working on a Xen port.
gnumach-1-branch-gdb-branch is a branch created by Michael Casadevall for working on GDB stubs.

Task List

Clean up the code
Open Issues
Update the core architecture and drivers
- Check what NetBSD, FreeBSD and Linux do with their host specific code (i486, PPC, Sparc, ...). And if it might be wise to take that and use it in GNU Mach. There is no need to worry about purely internal API's, but the external ones shouldn't require any major changes.
- Write a list of all functions provided by the host dependant code in GNU Mach that gets used in the non-host specific code (kernel, IPC and VM).
- Once we have decided what the new internal API should look like, make a list of the new API and the old one, and try to make things as compatible as possible, but not at the expense of anything.
Implement Migrating Threads
- Migrating Threads (MT) could improve IPC performance and making easier the work of the scheduler. For more information, check http://www.usenix.org/publications/library/proceedings/sf94/ford.html
Improve the external pagers interface
- Implement read-ahead (huge I/O improvements expected).
- Making this interface synchronous should improve I/O performance significantly, without (almost) any drawbacks (we also get some advantage from MT's).
- Implement more paging eviction policies, so they fit better with usual behaviour of the pagers.
- Implement resource accounting for external pagers.
VM
- Put it on user level
- Clean up the mess.
- Provide a fast way to read/write from/to a memory object.
- Simplify/normalise the code.
Simplify the IPC Semantics
- There are a lot of things in GNU Mach's IPC that we don't need. Track down those things, and get rid of them without requiring many changes in the Hurd (the changes will affect MiG, but that is OK).
Temporary mappings for Client-Server memory transfers
- Extend Mach's IPC to provide some kind of object which can represent a range of memory that can temporarily be mapped into the servers address space for sending/receiving data. This would allow us to avoid excessive memory copies.
- Find a new way to work with unaligned memory.
GDB remote debugging support
- Implement support for GDB debugging via serial line and/or network. Maybe this can be done together with the host-specific work above.
  
  See GDB stubs.
Make it run as a UNIX/Linux executable.
- Neal:
```
<neal> here's a fun project: port the mach interface to Linux
<neal> (e.g., via kernel modifications)
<neal> or, to posix/glibc
<neal> (mmap, some minimal ptrace, etc.)
```
- From the Hurd bits at sourceforge.net: http://hurd.cvs.sourceforge.net/hurd/gnumach-otop/, started by John Tobey. Last time touched in 2003. Status completely unknown.
  - README

Wish List

Interface for userspace non-critical drivers.
Sound Support
WLAN support (ipw2200) with WEP/WPA
ACPI support