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Aucbvax.2059 fa.works utzoo!duke!decvax!ucbvax!RYLAND@SRI-KL Fri Jul 3 09:35:48 1981 Re: Addressing and File Accessing Bill, the system you describe (System 38) is just a capability-based machine, which is certainly old hat by now. Unfortunately, this idea still seems to be barely catching on in the "real world." Most of the seminal systems (CAL at Berkeley, Hydra at CMU, and the Plessey System 250) were done and finished years ago, and yet there are only a few commercial systems which reflect this elegance of architecture (S38, Intel's 432 (in some sense), some ICL machines). Others are working on systems which embody these ideas (H-P's Bridge project, the S-1 project), but most of them bastardize the design for "practicality". I surmise that capability-based systems are finding life difficult because no one ultimately understands how to deal with them practically (e.g., the Hydra folks discovered quite a few problems with accounting (who owns an object?), backup, recovery, etc., though they also made great strides with some of the harder issues (mostly reliability).) I think a large percentage of us would be delighted to have a true capability-based machine if the performance were up to what we've come to expect from current architectures, but that doesn't seem to be around the corner (at least in any useable way: S38 hides all its good design from the user and masks it in the usual nonsense IBM business software.) -------

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