tim at rowledge.org
Fri Dec 30 19:36:36 CET 2005
On 30-Dec-05, at 2:44 AM, Lukas Renggli wrote:
>> The entire file system needs a full rewrite from bottom to top.
>> Anyone suggesting the 'you only need to implement the posix calls and
>> make it all work that way' will discover the power of telekinesis as
>> I use my Mighty Mental Powers to have them deliver a resounding
>> dopeslap to themselves.
> Yeah, but if anyone is interested into such a thing: I have done it
> already, the Unix/OS X VM plugin for POSIX file-handling ;-)
Well I hope the bruises are fading...
> I wrote
> it to reduce the number of layers and to track down problems we had
> with OmniBase. At least it solves the #size problem and provides some
> low-level primitives for locking. It is designed and optimized towards
> OmniBase, but I could also work on its own, I guess.
I'm happy it helps your particular problem but that is the root of
the problem I have with the idea of 'do it posix'. Y'see, posix isn't
universal. It misses things that are useful, it includes things that
can't be done on all platforms and it has a stupid name.
Since Squeak is aimed at being a very portable system it needs to be
built in a very careful, thoughtful manner. One has to take care to
provide as much access to paltform cleverness as possible without
making it impossible to work with a differently clever platform.
Trivial example - virtual memory is common on major desktop
platforms. Not universal but common. If we build a system that
*relies* upon it then we instantly exclude any platform that doesn't
have it; nice interesting things like pdas, webpads, cameras, phones,
routers, phaser guns (whoops, forget that one you're not supposed to
know about my work on them) and just about all embedded systems. Now
you might say that nothing relies on virtual memory and it's just
like having lots of ram but there is the problem - a belief in
always having lots of ram. Not always true.
Apologies for going all preachy but this is stuff I've spent twenty
years worrying about for a living. One thing you learn is that the
'obvious answer' usually looks really, really stupid a bit later
tim Rowledge; tim at rowledge.org; http://www.rowledge.org/tim
Strange OpCodes: CDC: Clear Disks and Crash
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