Date: Wed, 08 Nov 2000 13:16:00 -0800 From: Julian Elischer <julian@elischer.org> To: Terry Lambert <tlambert@primenet.com> Cc: Mike Smith <msmith@FreeBSD.ORG>, bruno schwander <bschwand@dvart.com>, freebsd-hackers@FreeBSD.ORG Subject: Re: close call in a device ? Message-ID: <3A09C290.DC5F0E3A@elischer.org> References: <200011082035.NAA25463@usr08.primenet.com>
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Terry Lambert wrote: > > > If I understand you correctly, you have multiple processes all of which > > are going to try to open /dev/foo, and you want them to behave as though > > they have each opened a unique device? > > > > You can't do this with FreeBSD, or with many other Unixes. > > Any SVR4 system can support this. So can AIX. > > > Arguably, this is a defect with the device model. If you are trying to > > fake up concurrent access to a device, and the client processes are only > > going to read and write (no ioctls) to this device, then you can use a > > fifo and a multiplexor process. > > > > Alternatively, and this would be recommended; fix the client program. > > Or fix the device model. You can't have multiple VMWARE sessions > in FreeBSD today because of this defect in the device model. I believe that this is not the reason.. it's another resource that we only have globally.. (i.e. once) but I forget what it is.. the problem here can be solved by using Poul's 'cloning device' interface in the driver. I don't think he has it quite completed but it is partly there.. maybe enough.. only in -current at the moment and you need to have devfs turned on. each time you open it, you actually get a different device and vnode.. > > Terry Lambert > terry@lambert.org > --- > Any opinions in this posting are my own and not those of my present > or previous employers. > > To Unsubscribe: send mail to majordomo@FreeBSD.org > with "unsubscribe freebsd-hackers" in the body of the message -- __--_|\ Julian Elischer / \ julian@elischer.org ( OZ ) World tour 2000 ---> X_.---._/ presently in: Budapest v To Unsubscribe: send mail to majordomo@FreeBSD.org with "unsubscribe freebsd-hackers" in the body of the message
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