What Should Be Incorporated Into BSD/OS
This is the list of things (with explanations) about what I think should
be incorporated into BSD/OS. Obviously, this is an opinion piece, and
everybody is free to read it, ignore it or go ahead and implement it. It
is my sincere hope that Wind River Systems (WRS) will continue to make
sure that BSD/OS remains technically relevant as a server and desktop
platform for many years to come. I have confidence that WRS can make
BSD/OS a success in the embedded OS market, but I think it
deserves far greater exposure than only embedded devices.
I have been a longtime user of the BSD/OS operating system. I started
using it before it was called BSD/OS, back when it was called BSD/386
(version 0.9.3). Over the course of several years while I worked at
UUNET, I had the opportunity to fund the incorporation of certain
features into the BSD/OS operating system. At UUNET, we thought these
features to be important enhancements that would be valuable to UUNET
down the road when deploying applications on top of this platform. Like
many experimental software features, some of these were useful, some were
not, some never actually got finished and/or delivered in a useful
Without a doubt, the most important, forward thinking feature that
UUNET was willing to fund in BSD/OS was the inclusion of a truly
symmetric, multi-processor design for the kernel. BSDi started this
implementation process, did a pretty good design and delivered a
not-ready for prime-time implementation of this system on both the
UltraSparc and x86 architectures in 1999.
The funding for this project provided the groundwork for two important
projects spawned from the same design work:
- The SMPng kernel design was taken from BSD/OS and given to the
FreeBSD project in early 2000. This design forms the basis of the the
SMP technology that FreeBSD is currently implementing (2000, 2001).
Please note -- this is not an attempt to sell short the FreeBSD's teams
efforts -- they have worked pretty hard at making this work in their
kernel tree. As of this writing (Oct 2001), however, it's not yet ready
for prime time.
- The ``BSDng'' work that Wind River's BSD/OS group is currently
working on in their ``Itasca'' project. (The name for this was finally
uttered publicly at the BSDCon 2002 conference, so I figure it is no
longer a secret.) I like to think of this project as the culmination of
the operating system work that I helped to guide through funding the
design and implementation process in 1998 and 1999. I believe this
fundamental reworking of how the BSD kernel works internally might be
the largest pervasive change to BSD kernel since the introduction of a
pageable VM system in the 3BSD release.
All that being said, the concepts listed below are what I think ought
to be incorporated into BSD/OS. Of course, it's always been easier to be
the ``armchair quarterback'' of specifying this, that and the other
thing, than actually being the one that have to make the code work. All
of these comments apply to the BSD/OS 4.3 release, which is the currently
shipping version of the operating system. I will update this document
after the next version ships (or at least a Beta release is
Many of these ideas are not new. I sent some of these ideas to to BSDi
in 1997, as part of a list of things we might be willing to fund. An
updated list was sent to BSDi in 1999 during another contract negotiation
period. I sent a revised list to BSDi in 2000. And I sent a newly revised
list again in 2001, a week after I quit my job at UUNET. I have not sent
a revised list to WRS since they bought the software assets of BSDi. But,
I started this web page instead, and made various members of the WRS
technical staff aware of its existence. I've been told that this document
has seen limited circulation internal to WRS.
I thought sharing my ideas about BSD/OS in a public forum would be a
good thing. Without cohesive thoughts about the future of the BSD/OS
operating system, who knows where it might be pushed. Lack of direction
is a horrible thing -- many large software projects have been killed due
to lack of vision. I've seen it happen up close, and it is a terrible
thing to see happen.
Application Enhancements List
Certain applications that are shipped with BSD/OS are ``contributed
software.'' Updating them to more current versions would alleviate the
need for customer sites to have do this again and again. These could
probably be fairly easily updated by non-intrusive patches to the current
released and supported versions of BSD/OS.
- Ship a newer version of
(Added November, 2002)(KJL)
BIND release that BSD/OS 4.3 ships with is old,
and has had numerous security problems during its lifetime. A newer,
better engineered, stable major version number release has
been available for quite a while.
BIND9. This is the
version of the nameserver that gets patches released for it first, and
is thought to be fundamentally more secure than any
BIND8.x release. Note: I am an employee of ISC, the
makers of the BIND software product. While I do not work on BIND, I
work with people that work on BIND.
Ship a newer
perl version (Added
perl interpreter that BSD/OS 4.3 ships with is
old, old, old. Two newer stable versions have been released
since the release that ships with BSD/OS.
Perl 5.8.0 is
the current stable release, and the well-regarded
5.6.1 release has been stable for over a year. Many free
software projects require some of the advanced debugging and diagnostic
features of a more modern perl than the old
that is shipped with BSD/OS 4.3.
Ship a newer
groff version (Added
groff installation that BSD/OS 4.3 ships with is
old and out of date. Several newer versions have been released. Of note
to European customers is the support for Euro symbol printing in
groff 1.18 and newer releases.
Ship a newer
version (Added November, 2001)(SMS)
ghostscript PostScript interpreter that BSD/OS 4.3
ships with is old. Several newer versions have been released under the
GPL. The newest GPL'd release should be included.
Update JAVA support (Added November,
2001)(SMS)(Updated March 2002)(KJL)
- Under BSD/OS 4.2, there was support for the JAVA 1.2.1 JRE and JDE.
This was useful for doing small-scale Java development and debugging.
Lack of a JIT compiler makes the JAVA runtime exceptionally slow, such
that the JRE is almost useless for running any large-scale
applications. In BSD/OS 4.3, the Java component was dropped from the
product release, due to reported licensing difficulties.
The Java support should be re-introduced and updated to the current
release of Java -- version 1.4. Making the hotspot JIT compiler work
would be a nice improvement as well. Without this level of native
platform Java support, it will be impossible to have a Java applet
support for Mozilla, among other consequences.
Update PINE mailer (Added November,
- Update the contributed software of the
pine mailer to
the latest release. The included version is very old and many
improvements have been made since that version was released.
LAP enhancements (Added November, 2001)(SMS)
- While the LAP emulation environment is pretty good and a novel way
of using the dynamic library linker, a small amount of kernel support
would probably go a long way to making this emulation more
fvwm2 window manager (Added
fvwm window manager that BSD/OS ships with is old.
Ancient, actually. It's the last stable patch release of the original
fvwm code base (version 1.24r), and is completely
unsupported and not being maintained. The developers have abandoned the
code, by and large, and have moved onto newer versions of
fvwm2. The current release of the stable branch is
2.4.3. More details are available at http://www.fvwm.org.
v16.5 (Added October, 2001)
- The latest stable release of the enlightenment window manager. This
version has been released for just shy of a year (only 5 more days to
go to be a year, as of this writing) and considered highly stable. This
version is one that support Xinerama. Rather than force the users that
wish to use enlightenment to go and compile it themselves, update the
shipped version. More details are available at http://www.enlightenment.org.
Update Apache to version 1.3.22 (Updated
- The latest and most secure version of Apache. Given that many of
the sites that are running BSD/OS provide web services, having an out
of date version of the webserver is counterproductive. Tracking the
Apache releases closely would be worthwhile.
Various IPFW improvements (Added September,
- This was a list of improvements that I felt would make IPFW work
better or fill in gaps in the system. These were sent as mail to the
Request For Enhancement (email@example.com) mailing alias, and nothing else
has been heard. So, I've dusted off my list, turned it into HTML and made it available.
Integrate KerberosV Support (Added November
- The KerberosIV support in BSD/OS is ancient. It has no hope of ever
working on anything other than a single interface, IPv4 machine. MIT
has stopped supporting this codebase and no new development is
happening in the world of kerberosIV. KerberosV is superior to
KerberosIV in almost every way -- except for code size -- it is
huge. However, the superior administration tools, the possibility
to work over more than just IPv4 networks, and the greater range of
flexibility in the system are a worthwhile tradeoff.
Kernel Enhancements List
The following list of things apply more to enhancements and additions
to the BSD/OS kernel. Often there would be related work in certain pieces
of user software that would need to be added or modified.
- Fix softrdonly mount option support
(Added March 2002)(KJL)
- The BSD/OS system introduced the
option in 4.0 BSD/OS. This option is supposed to allow for selectively
upgrading and downgrading a filesystem mount from rw to
ro on the fly. If there are no open writable file descriptors on
the filesystem, it should have all dirty blocked flushed to the disk
and have the mount downgraded to read-only and the superblock marked
clean. If a write operation takes place to the filesystem, rather than
failing with a
EROFS (read-only file system), the mount
point should be upgraded to read-write and the write should
Unfortunately, the support required to safely fully implement this
technology does not exist in the BSD/OS 4.x series of kernel. Nor is
likely to show up in a patch, as the changes required to support this
functionality are widespread throughout UFS. Use of this option can
result in lost data and damaged filesystems. I state this fact on
personal experience. Until the support is fixed, you should not
use this mount option.
Conveniently, Kirk McKusick has done the heavy lifting of making a
kernel framework for this type of operation work, in the form of his
UFS snapshots and running ``fsck'' in the background. This is a
great paper and worth spending the time to read it.
While merely adding the snapshot facility to BSD/OS will not
fix the softrdonly mount option, it does provide the necessary
framework to fix the problems with the current implementation. It is my
belief that fixing softrdonly after snapshot support is
in the kernel is a relatively easy thing to do. It should go without
saying why this is extremely valuable for an embedded operating system
-- having filesystems that don't need to be recovered after a system
crash or reboot speeds up reboot speeds considerably. On systems with
FLASH devices acting as the filesystem storage, not constantly updating
the UFS superblock is a huge gain. Not only does it reduce I/O
operations, but it also prolongs the life of the FLASH device. All
these things are extremely desirable in an embedded operating system.
These are all the reasons that BSDi originally put this mount option
into the system and they remain relevant today.
Implement kernel scheduled threads (Added
- By implementing kernel scheduled threads, applications that use
pthreads would be able to use multiple CPUs. Currently an application
that uses pthread can use only a single processor, so the total amount
of CPU available to a single application on a multiprocessor machine is
One way this could be addressed is porting the IBM Next Generation POSIX
Threads project from Linux to BSD/OS. This appears to be excellent
work for doing NxM thread to kernel thread multiplexing. Given that
this is licensed under the LGPL and not just the GPL it is possible to
consider using this software.
Support for 16650/16750 serial chips (Added
- With the discontinuance of the USENET-II ISA serial port controller
board, it is impossible to get true hardware flow control serial ports
under BSD/OS. With the USENET-II serial board, the 16550 serial chips
had a small amount of additional hardware added to implement true
hardware flow control. Without that hardware, the software driver must
still be called to turn on the serial port bits that indicate that
sender should stop transmitting.
By supporting the 16650 and 16750 serial controller ports natively (as
opposed to in 16550 compatibility mode), true hardware flow control can
be turned on in these controllers. This is relatively small change to
make to the serial driver, and would be useful for people attempting to
run very high speed serial ports under BSD/OS.
User writable LDTs so that
run (Added November, 2001)(SMS)
WINE is a emulator that runs on many different flavors
of UNIX-like operating systems, that provides some support for running
of MicroSoft applications. In order to make it possible to run this
emulator, the kernel would need to support user writable LDTs.
Adapt the FreeBSD new dirpref code in FFS
(Added October, 2001)
- A fine bit of optimization for how directories are laid out in FFS.
It improves performance in many areas and apparently doesn't hurt
performance anywhere. FreeBSD, NetBSD and OpenBSD all have this code
integrated. Kirk McKusick has done a review of the code, and I don't
think he had any great issue with it.
webpage for the original written details about the root of the
problem and the tests to show the problem.
There is no reason to have 1/10 the filesystem performance of the
other *BSD systems, given the relatively small number of changes needed
to implement this change.
The NetBSD project has further commentary on the commit they did here.
Implement kernel support for SSE instructions
(Added October, 2001)
- The Intel SSE (and SSE2) (Streaming SIMD Enhancements) instruction
sets offer the assembly programmer additional speed when writing
application programs. The SSE and SSE2 extensions require both support
from the CPU and from the operating system. BSD/OS should be altered to
provide the support that is required to allow SSE instructions to be
Resurrect the Sparc/UltraSparc port (Added June,
- Don't even get me started. Having a second supported architecture,
especially one that is of a different endian machine keeps the software
intellectually honest. Not to mention that in the SPARC world, it is
relatively easy to get multi-processor machines with more than 4
processors. This is an excellent area for proving the scaling (or lack
thereof) of the SMPng software architecture.
Implement IPFW filtering for IPv6 (Added
- Hook up support for filtering of IPv6 packets in IPFW. Most or all
of the low-level work to support IPv6 has already been added to the
IPFW system. But, the appropriate IPFW entry points have not been
wiring into the KAME IPv6 stack included in the kernel.
Port NetBSD UVM system to kernel when ready (Added
- The NetBSD UVM system is pretty nice looking. It seems to have a
robust design, with many desirable features. It is obviously cross
platform, and has been implemented on a wide variety of machine
architectures. This would also lead directly down the path of having a
unified kernel memory/disk buffer cache. The current VM system in
BSD/OS is showing its age.
This strikes me as a problem similar to the that of the historical 4.3
-> 4.4 release at CSRG. The new (Mach derived) VM system was a major
stumbling block for each architecture that needed support in the BSD4.4
release cycle. Enough of a stumbling block that BSD4.4 dropped support
for the VAX architecture -- mostly due to lack of support in the new VM
Port NetBSD USB framework (Added December
- Support for keyboards and mice at a bare minimum. Extension of USB
support for generic printer devices would be a very useful extension.
This would allow low-cost postscript printers could be attached via
this bus. A follow-on project would be to implement support for USB
attached scanners. Classes of so-called legacy-free devices
are available now -- these devices do not have anything but USB ports
for connectivity of keyboards and other input devices.
Port kqueue() kernel framework from FreeBSD
(Added December 2000)
- This is just plain good engineering work. It solves many of the
commonly encountered issues for UNIX applications handling a very large
number of file descriptors in a fairly elegant manner. Additionally, it
allows for a nice, low overhead, way of waiting for event to occur in
the filesystem (e.g. watching a directory).
Support PPPoE in the Kernel PPP stack (Added May
- PPPoE (PPP over Ethernet) is a popular connection mechanism for
many ISPs providing consumer oriented DSL connections. Sometimes also
found in use at cable modem operations. Having both the server side and
a client side implementation might be useful for ISPs. Having only the
client side would be useful for end users.
Support IPv6 in the Kernel PPP stack (Added May
- As IPv6 becomes more and more important to the world, in particular
the Far East, it is important to have it well supported for all types
of interfaces. Currently, IPv6 support is available for FDDI, Ethernet
and Gigabit Ethernet interfaces. Inclusion of IPv6 support in the
kernel PPP stack would add dialup and leased line interfaces to that
list. For developers wanting to experiment with IPv6 this would be an
Implement recvmfrom() system call (Added May
- A high performance syscall interface for getting multiple datagram
packets out of the kernel in a single system call. In crude terms, you
can think of this as being to
readv() is to
read(). This is critical for
certain high performance networking daemons, such as programs that need
to serve DNS queries or deal with RADIUS packets. Having a way of
writing multiple packets into the kernel in a single system call would
be useful as well, but probably not as important as a way to get
multiple packets out of the kernel quickly. It could be argued that to
make the system fully orthogonal, adding a multiple packet writing
command would be the right thing to do. The addition of this system
call would almost certainly be very useful for multi-media and
multicast applications in addition to the aforementioned
Implemented pread/preadv and pwrite/pwritev
system calls (Added December 1999)
- These system calls are similar to
writev()), except that a seek offset is in the argument
list, in addition to the fd, buffer pointer and size of the data. These
calls allow for easier writing of multiple datablocks into a file in a
multithreaded application. They are also of interest to people writing
database logging code.
Release new and improved select() system call
(Added November 1999)
- Faster, better, stronger, what's not to like? This was another
feature that UUNET funded in BSD/OS. I don't think that BSDi ever
managed to integrate this into a released kernel. Pity, they ought to
do it -- everything that uses
select() will get
Change select() system call to update timeout values (Added February
- A minor change to the
select() system call so that the
timeout value that is passed into the kernel is updated in the case
where the syscall completes before the timeout is reached. This would
be very useful for writing certain classes of applications that need to
have regularly scheduled operations happen, but at the same time, must
be responsive to other events that are occurring. This is a minor
change and is explicitly allowed as a possible behavior for the system.
sysctl() interface to toggle this behavior on and off
would be needed, at least during the phase after the above timeout code
is implemented, but before all the applications that improperly rely on
the existing behavior are fixed.
Implemented IEEE-1394 (FireWire) support
(Added October 1997)
- Add support into the system to be able to support devices on a
IEEE-1394 bus. This should be of sufficient quality to be able to
control at least a couple of video camera devices and capture the video
stream that one of those devices sends out the FireWire bus. Also be
able to read/write mass storage devices that located on the FireWire
bus (particularly disk drives).
The following is a list of things that fits into neither of the above
lists. Often a meta issue, which requires more than a single definable
act of engineering or development is required to address this item.
- Entice VMware to port to BSD/OS (Added November, 2001)(SMS)
- While BSD/OS is known to work as a VMware client operating system,
it would be extremely useful to have BSD/OS also be able to act the
hosting system. Being able to host other virtual x86 machine instances
would be useful to just about everybody that needs to work in more than
one PC based operating environment.
Open Source the IPFW kernel subsystem (Added December 2000)
- The BSD/OS IPFW system is an excellent piece of software
engineering. Releasing it so all the BSD systems can have a unified
packet filtering system would be great. Unfortunately, it might well be
too late to have any of the other BSD groups gladly adopt it as their
packet filtering system. They have all invested time and effort in
their own filtering systems. Additionally, I am afraid that the not
invented here (NIH) meme will cause this code to be ignored, even if it
were to be released. However, that isn't a forgone conclusion, so the
IPFW code should be released.
Well, there you have it. Some of my thoughts on what would make the
BSD/OS operating system a nicer place in which to work and play. If you
have a thought or two about this, feel free to send them to me. If you
can convince me that it's a good idea, I'll be happy to add it to my list
and give you credit. If you don't convince me its a good idea, well, I
might not add it to my list, but there is nothing stopping you from
making your own list.
Copyright (c) 1997, 1998, 1999, 2000, 2001, 2002 Kurt J. Lidl. All rights
Portions Copyright (c) 2001 Steven M. Schultz. All rights reserved.
Redistributions of this information must retain the above copyright
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$Date: 2007/12/07 02:57:23 $