Relay-Version: version B 2.10 5/3/83; site utzoo.UUCP Path: utzoo!chp!rph From: rph@chp.UUCP Newsgroups: comp.sys.m6809 Subject: Re: 512K RAM upgrades Message-ID: <1987Aug19.210404.455@chp.uucp> Date: Wed, 19-Aug-87 21:04:04 EDT Article-I.D.: chp.1987Aug19.210404.455 Posted: Wed Aug 19 21:04:04 1987 Date-Received: Fri, 21-Aug-87 06:06:27 EDT References: <5013@milano.UUCP> Reply-To: rph@chp.UUCP (Pontus Hedman) Organization: The Coach House Press Lines: 35 Keywords: OS9 CACHE SDOS Checksum: 47039 In article <1997@lsuc.UUCP> jimomura@lsuc.UUCP (Jim Omura) writes: > Well, I have to disagree with the trend here. I don't like full >cache for OS-9 systems. There are a *lot* of different approaches to >speed and system integrity. Full read/write cache adds speed but at >substantial risk of data loss and file corruption in the case of power >failure or other hardware flakey failure. Thanks guys, but no thanks. >Data integrity is too important for me to risk that. Read cache--which >was done by TLM on the Atari ST OS-9 port was, in my opinion, the >best compromise. Keep in mind that OS-9 allows you to *preload* >object files. This is much more efficient than cache. Secondly, >for datafiles, it's faster to throw intermediate files and reasonably >small files into a RAM disk. If a file won't fit in, say a 512K RAM >disk, a cache isn't likely to help that much either. A RAM disk has >most of the same problems for data integrity as a cache, but at least >you have an inherently better chance of retaining the "old copy" intact >even if you lose the copy in RAM disk. A partially updated disk copy >when the power goes down (or other "bad crash") is generally worthless. > >Cheers! -- Jim O. Humph. I've been running full R/W caching 24h/day for a year now and haven't had any problems. The cache typically clears out within less than half a minute of disk activity finishing, and if I'm about to test some dangerous program, I manually flush the cache (some kind of manual cache-flushing has to be provided anyway for when you want to change disks). I haven't had any kind of disaster that I couldn't fix with DCHECK. I write stuff in C and ASM and haven't yet lost a file. I used my extra RAM here as a ramdisk before. I find R/W caching much faster and trouble-free. For C, for example, the edit-compile-test cycle simply became shorter (admittedly I have only 32k to use for ramdisk/caching; with bigger memory sizes a ramdisk might be faster). -- Pontus Hedman {utzoo|utgpu}!chp!rph