Re: [9fans] Ephase question.

["Douglas A. Gwyn" <DAGwyn@null.net>]

"rob pike, esq." wrote:
> Of course you could provide a garbage collector
> but that opens a whole new world of trouble.

That's the sort of thing I had in mind.  Unused resources
can *in principle* be reclaimed without the resource client's
explicit participation.  How practical it would be is another
question, and I'm not proposing that real systems be boiled
down to minimal possible facilities that are hard to use.
(Otherwise we'd all be given just gate arrays to program.)

> In any case, who cares?  As you said, it's academic.

Doesn't mean that it's not worth thinking about.  Sometimes
good ideas emerge that can be adapted into useful practice.

> ... rfork is really a set of calls encoded with a bitvector.

Indeed there have been several composite "spawn" implementations;
while simplicity might be hard to measure accurately, a single
call with lots of parameters doesn't seem as simple as a couple
of calls with very few parameters.

> Nobody asks what the minimum libc interface is, ...

To some degree we do.  How much *has* to be provided by each
specific C implementation in order for a user to be able to
provide his own portable implementation of all the standard
library?  In the embedded-processor world I find that such
questions can be of urgent practical importance.

A similar question is, what is the minimum synchronization
mechanism needed to coordinate threads?  Add "efficiently".
Mutexes seem to be the answer, but if someone knows better
I'd appreciate hearing about it.

> What matters is expressibility without bloat, not finding
> the criteria under which to claim a lower count of
> functions of type T, for some T.

It can depend on one's goal.  For example, if a primary goal
is proof of security, it seems intractible unless the number
of primitive functions is fairly small and each has a fairly
clean specification.  Reliability and correctness, ditto.
English is very expressive, but problematic for purposes of
precise specification.  It would be meaningful and potentially
useful for linguists to consider minimal requirements for an
equally expressive but precise natural language.  (Leaving
aside any requirement for intentional ambiguity, which for
the most part is also a working assumption for OS services.)