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Path: euryale.cc.adfa.oz.au!newshost.carno.net.au!harbinger.cc.monash.edu.au!munnari.OZ.AU!news.ecn.uoknor.edu!feed1.news.erols.com!newsfeed.nacamar.de!fu-berlin.de!irz401!orion.sax.de!uriah.heep!news From: j@uriah.heep.sax.de (J Wunsch) Newsgroups: comp.unix.bsd.freebsd.misc Subject: Re: mmap() incapable of mapping block special files Date: 2 Jun 1997 21:15:17 GMT Organization: Private BSD site, Dresden Lines: 29 Message-ID: <5mvd55$c7o@uriah.heep.sax.de> References: <ytlraemlumg.fsf@mr.net> Reply-To: joerg_wunsch@uriah.heep.sax.de (Joerg Wunsch) NNTP-Posting-Host: localhost.heep.sax.de Mime-Version: 1.0 Content-Type: text/plain; charset=ISO-8859-1 Content-Transfer-Encoding: 8bit X-Newsreader: knews 0.9.6 X-Phone: +49-351-2012 669 X-PGP-Fingerprint: DC 47 E6 E4 FF A6 E9 8F 93 21 E0 7D F9 12 D6 4E Xref: euryale.cc.adfa.oz.au comp.unix.bsd.freebsd.misc:42091 Scott Fritchie <fritchie@mr.net> wrote: > I'm tempted to add an additional "&&" to the file type test to include > for VBLK ... but I wouldn't wanna do it if it will cause unknown (to > me) mischief down the road. Is there a particular reason why VBLK > isn't included? It's not unlikely that the VM system (for the filesystem buffer cache which you're involving then) would get into your way. My gut feeling says that you should notice this quickly (by crashing your system a horrible death, with all the disks potentially trashed) if you gave it a try. :) Also, why do you want it? Why are you going to blast the buffer cache with the mmap data? Either you've got a device which you can meaningfully map at all (since it provides for some method to access a shared memory region or such, like a framebuffer), but then you won't love to see the buffer cache making decisions of its own about when to flush data back to the device. Or, the device doesn't provide this feature, but then, what semantics would you expect from mmapping it? But as Julian wrote, best discuss this on the mailinglist. -- cheers, J"org joerg_wunsch@uriah.heep.sax.de -- http://www.sax.de/~joerg/ -- NIC: JW11-RIPE Never trust an operating system you don't have sources for. ;-)