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SubjectRe: 2.2.0 wishlist
Alan wrote:

>> No. STREAMS much more powerful than current interface is.

> Also much too slow.

>> You can emulate BSD socket interface (and ttys, and....) on the top of
>> STREAMS (f.e. Solaris-2.*), but the reversed task is impossible.
>> Only poor emulation, that is useless.

> You can emulate the whole of the user view of streams in user space,
> properly and accurately with only a few small kernel hooks for the
> operations sockets don't represent. And note that almost all of those
> like
> querying the next pending connection before accepting it are covered
> in the Posix draft socket api

Am I missing the point? We are talking about kernel STREAMS?
That _very_ good idea of modularising functionality? The idea
that makes writing device-drivers easier. (well, they don't make
it any harder). That allows protocols stacks to sit nicely
on top of each other. That allows module re-use (PUSH an encrypting
module into your down/up stream). That allows multiplexers (de-muxs)
to be easily written :)
That can help in multi-threading a kernel (multiple-thread the
STREAMS correctly, and the drivers/modules follow - well, almost, yes?).
That can be used to pass data directly between a device's dual-ported
memory up into user's process. Ah, those lovely 'cloning' devices.
Being able to pass pipes between unrealted processes....

I first met kernel STREAMS a few years back (writing STREAMS drivers/
modules for an ISDN protocol stack). Yes, the concept does have
a few faults, and nasty kludges in some places to make them usable
as sockets. I cannot agree they are 'too slow'.

IMHO, STREAMS do bring a benefit to user space, but the largest
gain is within the kernel (they make it a much more friendlier place
to live, and code). Trying emulating them in user space sounds
strange to me. I guess you were stating that it is theoritically
possible?

markhe


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