On Jun 18, 2007, at 19:51 , Creighton Hogg wrote:
The hypothetical Haskell OS, especially if it were targeted toward 64 bit machines, could keep processes from messing with each other by way of language based security, and run them all in a single memory space. (The first system to do this, I believe, was the MULTIPOP timesharing system, but there are other precedents, too.) This would eliminate or simplify lots of context switches and buffer copies and memory management and other nastiness that now goes into kernels.
Okay, I remember seeing an example of this before , but I'm not sure if I see what language based security Haskell's type system could provide in protecting address spaces from each other. Normally I've seen capabilities used so that you can't access anything you can't name. Can you elaborate a little?
He's saying that the language itself prevents programs from writing outside their address spaces or (via things like STM or runST) accessing resources they don't "own". Which is a nice theory, but is dependent on the runtime not being buggy (I think some problems have been demonstrated with large arrays in GHC...). -- brandon s. allbery [solaris,freebsd,perl,pugs,haskell] allbery@kf8nh.com system administrator [openafs,heimdal,too many hats] allbery@ece.cmu.edu electrical and computer engineering, carnegie mellon university KF8NH