Path: utzoo!attcan!uunet!samsung!know!zaphod.mps.ohio-state.edu!usc!snorkelwacker!bu.edu!xylogics!transfer!crackers!m2c!umvlsi!dime!dime.cs.umass.edu!moss From: moss@cs.umass.edu (Eliot Moss) Newsgroups: comp.arch Subject: Re: Mixing paging and IO is inefficient (was Re: Compiler partions) Message-ID: Date: 27 Jun 90 12:50:23 GMT References: <137770@sun.Eng.Sun.COM> <1990Jun26.152907.979@cbnewsi.att.com> Sender: news@dime.cs.umass.edu Reply-To: moss@cs.umass.edu Organization: Dept of Comp and Info Sci, Univ of Mass (Amherst) Lines: 30 In-reply-to: yam@cbnewsi.att.com's message of 26 Jun 90 15:29:07 GMT In article <1990Jun26.152907.979@cbnewsi.att.com> yam@cbnewsi.att.com (toshihiko.yamakami) writes: Dangling pointers? In general computation, it might be true. In case of temporary compiler output files, isn't it enough just try to "make" again? If something wrong, let's try "make clean" and "make". Or did I miss some other important points? The problem is that the file system structure itself (inodes, free block info, etc.) can get somewhat scrambled, such that it is not even a legal file system structure. An earlier poster pointed out that synchronous writes are stronger than what is needed; a weaker sufficient condition is ordered writes: certain blocks should be written before others. Whether they lag reality may not be important in many cases, and in the cases that it is one can doa "sync" (or similar) operation, perhaps on a single file, set of files, directory, etc., rather than a whole file system. We may end up moving more towards the functionality provided by transaction processing systems, with ordered logging and so forth, but with most actions running with forced commits of data to disk (a significant difference from the transaction processing world). We probably have about beat this to death though ..... Eliot -- J. Eliot B. Moss, Assistant Professor Department of Computer and Information Science Lederle Graduate Research Center University of Massachusetts Amherst, MA 01003 (413) 545-4206; Moss@cs.umass.edu