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13:56:45
beach
Speaking of CLOSOS, I am reading "Modern Operating Systems" by Tanenbaum and Bos, specifically about the difference in performance between "kernel threads" and "user threads". If I understand things right, "kernel threads" are slower because scheduling requires a context switch involving a trap, a switch of address space translation, and a cache flush.
13:57:55
beach
Luckily, since CLOSOS code always runs in privileged mode and since it is a single-address-space system, none of those time-consuming actions should be required.
14:04:03
heisig
beach: That is a very interesting thought. Basically, the context switch is made obsolete by using first class global environments. Wow.
14:06:00
beach
But yeah, more evidence that current hardware was made to emulate multiple bare machines from the 1960s.
14:07:02
beach
It argued that a very large fraction of the silicon in a modern processor is dedicated to making it look like a C machine.
14:09:03
heisig
shka__: What I meant is, you can only run everything in kernel space because there is another mechanism for isolation - first class global environments and controlled access.
14:09:35
shka__
heisig: yeah, but that applies to everything that would run in kernel space, not just threads
14:11:47
beach
Hmm. So the next natural step (after CLOSOS) would be to think about how hardware could be simplified if we abandon this PDP-11 compatibility idea.
14:24:04
pfdietz
As seen on HN: doing IO in Linux without entering the kernel. No system calls. http://git.kernel.dk/cgit/linux-block/commit/?h=aio-poll&id=5aeaa1ad235c708e31ad930d1ff6ba6fd39bee91
16:39:43
beach
I think we have a near-final version of the bootstrapping paper: http://metamodular.com/bootstrapping.pdf simply because it is almost 8 pages long and that's the max. :)
16:40:23
beach
Seriously, we have tried to incorporate most of the remarks that several people so kindly provided.
16:42:13
beach
It's a bit embarrassing that three of the five references are my own papers. I guess we should add the Common Lisp standard and a few more default ones.
16:44:09
beach
With that, I think I will call it a day. I will hang out here until my (admittedly small) family announces that dinner is ready around an hour from now, but I don't think I am able to do any more serious work today.