From mboxrd@z Thu Jan 1 00:00:00 1970 X-Spam-Checker-Version: SpamAssassin 3.4.4 (2020-01-24) on polar.synack.me X-Spam-Level: X-Spam-Status: No, score=0.2 required=5.0 tests=BAYES_00,INVALID_MSGID, REPLYTO_WITHOUT_TO_CC autolearn=no autolearn_force=no version=3.4.4 X-Google-Language: ENGLISH,ASCII-7-bit X-Google-Thread: 103376,a1868a27625c21e7 X-Google-Attributes: gid103376,public From: kilgallen@eisner.decus.org (Larry Kilgallen) Subject: Re: Looking for keyed file package Date: 1999/09/24 Message-ID: <1999Sep24.130829.1@eisner>#1/1 X-Deja-AN: 529122137 X-Nntp-Posting-Host: eisner.decus.org References: <37E817C6.80ED41E0@easystreet.com> <7saii8$5bl$1@nnrp1.deja.com> <7scrba$bdu$1@clnews.edf.fr> <7semeb$69u$1@nnrp1.deja.com> <7seobv$7ib$1@nnrp1.deja.com> X-Trace: news.decus.org 938192912 7977 KILGALLEN [216.44.122.34] Organization: LJK Software Reply-To: Kilgallen@eisner.decus.org.nospam Newsgroups: comp.lang.ada Date: 1999-09-24T00:00:00+00:00 List-Id: In article <7seobv$7ib$1@nnrp1.deja.com>, Robert Dewar writes: > One thing to be aware of here is that a naive implementation of > indexed files may well be slower than using a database built on > top of a sophisticated indexed file system. I think the original poster said the project had a 4 week useful lifespan, so it seems me Implementation Time would dominate. > It is quite surprising what can be done with good indexed > file systems. For example, the Realia COBOL compiler uses a > sophisticated form of leading/trailing key compression which > results in an average stored key length of about 16 bits, > regardless of the actual physical key length. The VMS implementation of RMS does key compression and data compression as well, but I think that all started back when disk and memory space were much more dear. I/O bandwidth one area of computer performance that does not seem to be advancing so much as the others, so these days typical advice might be to engage in extensive caching of the index data if performance is important. Larry Kilgallen