Date: Wed, 2 Apr 1997 18:09:53 -0800 (PST) From: Mike Pritchard <mpp> To: hackers Subject: Re: Internal clock Message-ID: <199704030209.SAA17013@freefall.freebsd.org> In-Reply-To: <19970402210817.YJ08249@uriah.heep.sax.de> from "J Wunsch" at Apr 2, 97 09:08:17 pm
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J Wunsch wrote: > > Once i've sorted these problems out, i'll continue to make DEVFS > usable as a default. If persistancy is once the last remaining > problem, and nobody is stepping forward to implement the all-singing- > all-dancing union layer shadowing solution, i'll probably implement a > startup/shutdown script-based solution. If something better comes up > later, it can still be replaced. > > I think FreeBSD 3.0 might be shipping with DEVFS as the default, but > it's still ``quarter o'mile'' to go. I like the idea that someone posted about keeping some type of data file in the mount-point directory. This could be implemented similar to how the quota data files are handled. Manage it as a sparse file so that unused information isn't taking up disk space. On attribute change of a devfs device, the file system code seeks to something like major*minor*structsize in the devfs file and writes the information out. A zero entry means use the defaults. At boot time it reads the information structure for each major/minor that is configured into the system. The overhead of this should be even less than that of the quota system, since only attribute changes need to be tracked, not allocations. With the proper tools, a system like this should also allow you to set permissions for devices that are not currently configured into the system. You get the idea. The quota system also allows you to specify an alternate location/file name for the quota file, so devfs could do something similar. -- Mike Pritchard mpp@FreeBSD.org "Go that way. Really fast. If something gets in your way, turn"
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