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> Consider: > > 1. The measured performance of the best JVM sucks. 2. There is no > possibility of hard real-time in a garbage-collected runtime. 3. > The amount of code needed to implement a decent JVM (or similar > system) is approximately 10x the amount of code needed to implement > a protected microkernel. > that was not my point. it was an example that software-based memory protection is already practicable at acceptable costs. there are probably many ways of making memory protection software based with less overhead. i could also argue that in some fields of application program-verification works, so (leaving inconsitencies caused by concurrency aside) there is no overhead at all added and the operating system environment is unequally simpler than anything beyond DOS :) to make a clear conculsion: all that i am saying is, that the complexity introduced by highly modular OSes in order to adapt to former/common principles of OS-Development/Design/etc might be a sign that these former/common principles are wrong for the aims of such highly modular OSes. > Next time your life depends on the software being right, which one > would you rather depend on? > >> today the programming languages and its environments allow a much >> finer granularity of modularity. > > > You also mentioned sharing. Sharing isn't the solution to > robustness. It's the *problem*. i didnt say that either. i said that sharing is more complex in non-SAS environments and that there are no restrictions in SAS-environments about what entity shares which objects. > Shared-memory concurrency is known to be a completely > non-engineerable approach. > > Finer granularity is not always better. The trick is to discover > the finest granularity that real programmers can manage > successfully. Unfortunately, there seem to be different answers for > program structure (the object boundary) than for protection > structure (the subsystem boundary). true. So long... niklas > > > shap > -----BEGIN PGP SIGNATURE----- Version: GnuPG v1.4.3 (GNU/Linux) Comment: Using GnuPG with Thunderbird - http://enigmail.mozdev.org iD8DBQFEY46t+k24EnBNzsMRAutUAJ4qLHlEmISaHlMB5D4JWNZJK8zqHwCcCTx3 DHqwZHe0deMw83mGgXomb2I= =WojR -----END PGP SIGNATURE----- _______________________________________________ L4-hurd mailing list [email protected] http://lists.gnu.org/mailman/listinfo/l4-hurd
