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- From: mdchaney@fractal.ucs.indiana.edu (M Darrin Chaney)
- Subject: Re: Comparison of Alpha, MIPS and PA-RISC-II wanted
- Message-ID: <Bzo3tJ.KGo@usenet.ucs.indiana.edu>
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- Organization: Indiana University, Bloomington
- References: <BzIxqo.C90@dscomsa.desy.de> <BzKGKB.2Bp@pix.com> <1992Dec21.103432.294@rlgsc.com>
- Date: Tue, 22 Dec 1992 15:46:31 GMT
- Lines: 52
-
- In article <1992Dec21.103432.294@rlgsc.com> gezelter@rlgsc.com writes:
- >In article <BzKGKB.2Bp@pix.com>, stripes@pix.com (Josh Osborne) writes:
- >> The we need a way for user level code to tell the OS what file info is
- >> important to cache, and what isn't. Then you can be almost as efficent
- >> as VMS/RMS (you will have extra context switch overhead for the extra
- >> syscalls), but you will still be able to allow any user to create new
- >> filetypes.
- >--
- >Josh,
- >
- >Important point that you bring up tangentially in your post.
- >While VMS does provide RMS as an operating system service, there
- >is nothing which prevents you from "folling your own" type of
- >file structure. However, every program which wants to read from
- >your special file structure will have to be intimately familiar
- >with it. Programs which use RMS can process files which were
- >created using RMS with no problems.
- >
- >A misnote about the HSC which appeared in this thread. The HSC
- >does not really know anything about the content of the disk
- >files. However, RMS will do things inside of the CPU, such as
- >maintain index caches on a system wide basis, which are a
- >signifigant performance improvement. One problem with rolling
- >yourself is that, invariably, the management and monitoring tools
- >and utilities are bare-bones.
- >
- >- Bob
-
- Actually, I've seen alot of people here call RMS "the file system." For those
- of you who still think that RMS is the file system, I'll clue you in: RMS
- is not the file system.
-
- Let's think of what RMS stands for: "Record Management Services." Hmm, sounds
- more like a record manager than a file system, doesn't it though.
-
- The file system is accessed via QIO calls, and knows nothing about file
- formats. All it knows about is disks and files, files via file ids. It is
- actually easy to open a file by id and read virtual blocks from it. If you
- want to roll your own Unix functions (fread and fwrite), this is the way
- to do it. It might be a little faster, and you needn't worry about RMS.
-
- For stream-lf files, just buffer those blocks, and keep track of where the
- lf is. It's not difficult, and you can easily get around the 65534 limit
- that RMS places on files. Have fun...
-
- Darrin
-
- --
-
- mdchaney@iubacs mdchaney@bronze.ucs.indiana.edu mdchaney@rose.ucs.indiana.edu
-
- "I want- I need- to live, to see it all..."
-