Date: Mon, 29 Sep 2003 20:29:43 -0400 From: Sergey Babkin <babkin@bellatlantic.net> To: Peter Jeremy <peterjeremy@optushome.com.au> Cc: hackers@freebsd.org Subject: Re: has anyone installed 5.1 from a SCSI CD? Message-ID: <3F78CE77.5878B57A@bellatlantic.net> References: <3F775D41.DF780001@bellatlantic.net> <20030929075809.GA3062@server.c211-28-27-130.belrs2.nsw.optusnet.com.au>
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Peter Jeremy wrote: > > On Sun, Sep 28, 2003 at 06:14:25PM -0400, Sergey Babkin wrote: > >BTW, I have another related issue too: since at least 4.7 > >all the disk device nodes have charcater device entries in /dev. > > As of December 1999 - which is before 4.0-RELEASE. This was well > advertised and discussed at the time. Your objections are about > 4 years too late. Well, the previous version I installed was 4.0-snapshot that did not have this change yet. Also it's never too late to fix the broken things. > >That's very, very wrong. Even though there may be no difference > >any more between the charcater and block drivers, the type of > >device node still conveys the information about device types > >to the applications. One case in point being a viewer application > >(if anyone is interested, http://nac.sf.net ) which must handle > >the sequential and random-access devices differently: > > 'block' vs 'character' has nothing to do with random or sequential > access and any application that thinks it does is broken. Any > application that directly accesses devices must understand all the > various quirks - ability to seek, block size(s) supported, side- The random-access devices are seekable by definition. And the OS interface is there to hide the block size issues. > The only purpose for block devices was to provide a cache for disk > devices. It makes far more sense for this caching to be tightly > coupled into the filesystem code where the cache characteristics > can be better controlled. What I'm saying is that it's good to have an easy way for applications to distinguish the random-access devices from the sequential-only-acces devices. Are they cacned internally or not is not that much of an application's concern. -SB
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