Wed, 9 Nov 1994 12:30:38 +0800
I think that Mike and Jecel have hit the nail on the head. Until there
is a clear concensus on what this group will do, all the technical talk
in the world is not going to come to anything.
In order to lay the ground for discussion, I want to bring up some
topics that I think need to be discussed. These things come from the
recent work I did with distributed OO hard real-time systems and
What I would like to see in the MOOSE TUNES project goals:
- OO all the way down. Polymorphism is your friend. Whether it is done
in some nifty language like Self or in a kind of kludge like X-Windows
widgets, I don't really care. My ego is not on the line about what
language we use _as_ _long_ _as_ _it_ _does_ _not_ _constrain_ _us_!
I would like to see garbage collection support deep into the language
and system. I have yet to see an argument against garbage collection
that I can't refute with a few references to papers. I also want to
see support for persistence. I think that persistent object stores
can replace file systems eventually in a more flexible way.
- mechanism not policy. Provide mechanism at the low level and let policy
be decided by higher level entities. E.g. provide a way to switch tasks,
but allow difference schedulers to be used. Provide a way to send
messages, but do not force a single way of using them. This is the
microkernel way, but can be applied to any level in the system.
- distribution, but don't go overboard. Distribution is poorly understood
at best. After a couple of months of research I have found that there
are few or none who can even approach distributed systems in any serious
analytical way without making such drastic simplifications that their
models are almost useless. Distribution and parallelism are often
Rather than trying to make the perfect distributed system on a first go,
I would much rather see an approach that allows all kinds of distribution
models to be tried. This kind of goal can be met in large part by close
adherence to the second goal above. Allow systems to talk to each other,
but do not enforce a single kind of interaction. Go with the kinds of
mechanisms that do not preclude the use of higher level protocols. For
instance, a lot can be built on a datagram model of distributed messaging.
I want to see object migration possible under MOOSE TUNES. This is a
very powerful concept and should be looked at closely. If we play our
cards correctly with the object model and platform independence stuff,
I think we can make it so that object migration does not need low level
support and can be handled on the system or language level. Provide
a mechanism for object migration and it can be used by automatic load
balancing code or directly by users themselves. Let the higher levels
- platform independence. Make a reasonable attempt to avoid things that
would make MOOSE TUNES incapable of running on most platforms. If we
use transputer messaging or x86 segments, we will not be able to easily
port code to other platforms that don't have these "features". I think
that it is worth sacrificing a lot of performance in order to achieve
a high level of hardware independence. You can always performance tune
things later. First let's design with hardware independence in mind.
For all that I can't stand Micro$oft, their HAL layer in NT is not a bad
idea. I think that the definition of such a layer would be a good thing
to look at _after_ we have made some decisions about the other goals.
- support standards _where feasible_. I don't expect to be able to take
the ELF binaries off my Sparc and run them under TUNES tomorrow.
However, it would be nice if TUNES machines could at least support
socket connections from the outside world, deal with some UNIX-style
security issues etc. It would be nice if I could have a TUNES system
do some talking to a "standard" network. I am not asking to be able
to run my binaries, just that there is some support for working with
such older systems. If that means that we need to write UNIX/PC/MAC-side
support routines to allow us to use TUNES from such a platform, that will
just make TUNES more palatable.
- wheels were invented a long time ago, let's not to reinvent them. Truly
new ideas are surprisingly rare. All the research I have done indicates
that 99.9% of supposedly new ideas were written up several years ago
and tested. I will send a bibliography after this message. I encourage
people to read this stuff. I always learn new things and see new problems.
Some of the seemingly simple solutions I have seen posted here have
hidden catches that you might only find after doing exhaustive testing.
Don't get me wrong. New ideas are very good and very necessary. However,
don't let your egos get on the line about this. A lot of extremely bright
men and women have struggled and are still struggling with the kinds of
things we are talking about. It is pure hubris and egomania to assume
that our ideas are either new or perfect. Maybe some are, but only one
out of a thousand is truly new _and_ useful. Often it is very hard to
determine just how useful until a long time has passed.
There is absolutely nothing wrong with using old designs. Sometimes you
need to call into question basic fundamentals, but make sure that there
is a reason for it. There are very sound reasons why airplane wings are
not swept forward on most planes. It can be done (X-29 to mention but
one try), but not without a firm grasp of how to get around the problems.
Let us try to build on proven ideas _where possible_. If you start out
with a solid foundation, you eliminate a lot of uncertainty and gain a
lot of confidence. If we have the choice between an idea that is well
proven and understood and one that is promised to be better (faster,
smaller, lighter, fewer calories etc.), let's use the proven one and
test the new one. There are so many places things can go wrong in a
system with the kind of complexity we are talking about that it makes
sense to go with an incremental approach.
I would love to see a test platform that runs on top of UNIX or the Mac
or Windows or some other proven system before people start trying to
make pure MOOSE TUNES partitions on their harddisks. Such a platform
can also be a good aid in helping us define a HAL layer that can then
be ported to all the hardware we could want.
It is not a sin to build incrementally. It is a sin to think that you
can build it all at once and have it work. I realize that a lot of
people like to code. Be aware that well controlled software projects
spend less than 20% of the total project person-hours coding and that
a good portion of that time is for testing. The well run projects I
have seen (few and far between) seem to have more like 10% of the time
spent coding. Such projects take a very small amount of time to reach
their goals compared to ones that start hacking from the first day. They
are more adaptable to change. They are easier to maintain. Etc. etc.
If you have a idea for something technical, but it is about something
we have not started discussing as a group, just jot it down somewhere
and see if you can find other work that is similar or that will give
you some data. It would be a lot of help to the group if people would
take the time to think through their ideas carefully and do this
checking. We can move much faster and we will certainly all learn a
lot more. If you find other work supporting your idea, it is much
more likely that people will agree with it. If you find that the
evidence is against your idea, you can post that too and use it to
argue against the idea if someone else proposes it.
I can go on with the sermon for hours, but if you don't believe it from
the beginning and work with some real guidelines like these in mind you
will not be using your abilities to their full nor participating as much
as you could in this project. Everyone has a contribution to make and
a new way of seeing things. The best organizations are those in
which people are encouraged to check their own ideas and look for new
ones in others' work. There are many thousands of theses published
each year, surely there are few useful ideas in them. This doesn't
count the books and journal articles. Who knows what is published in
You may see this sermon as being an example of such egotism on my part.
I have had this stuff work for me and I know of places where it works.
I have read about it working in yet more places ("Managing the Software
Process" is a good place to start reading). I have never heard about it
failing completely*. I have had projects fail deadlines and even fail
completely due to disorganized approaches. I have heard and read about other
projects with similar problems. I think this gives me some justification
in making the points I made above. It is not that such organization is
guaranteed to make projects work smoothly every time, it is that with
such ideas, project _tend_ to go more smoothly. Without such ideas,
few projects do well.
* That is to say that I have never heard of projects that really used
these things and failed due to that use. Lots of projects use the
most wonderful origanizational ideas and then fail for reasons entirely
outside the scope of the project like having their funding taken away.
In short, what I would like to see for MOOSE TUNES are the following
- OO model with GC and persistence built in at a very low level,
- datagram-style message passing at a very low level,
- separate mechanism and policy from the first instant and at every level,
- distribution supported at a fairly high level (language or system),
- platform independence; I want to run heterogeneous MOOSE TUNES networks,
- work with standards where feasible,
- research, research, research; no new wheels please.
I think Mike has done a pretty good job of hammering a sort of initial
organizational charter into place. I tend to have a bit of worry (like
some others apparently) that there are a lot of officers and few soldiers
in this army. I think that the General Coordinator (was Secretary) is
a good position to keep, but that other coordinators should have several
projects each. Each project should be internally self organizing. The
coordinator for a project just looks over their progress from time to
time and makes sure that they are going in more or less the right direction.
Each project might have a project leader to manage the day to day activities
but _only_ if there are enough people in the project to warrant such a
position. It would not be a very good use of our time to have a project
leader for project with less than, say, three people. So, initially,
a General Coordinator and maybe one other project coordinator to handle
all the initial projects. No more than that many permanent positions
until we have more than five or six simultaneous projects.
The point was made that all this voting on each and every issue will
take all our time. I tend to agree with this to an extent. However,
if the General Coordinator is given the power to make decisions, then
the other people need to have the power to override that decision.
This may be where the 2/3 majority rule could be used. Most decisions
need not be voted on and will be acceptable to most people.
Does anyone have any references to work on organizing such things?
Robert's Rules of Order? Non-Profit Business Organization? (I am
stabbing in the dark here.) After all, I have to apply the above ideas
to all aspects of our organization :-)
I think we want to try to get some of the following "gee whiz" terms
in the name:
Network, Parallel, Object, Distribution, Heterogenous... Any more?