Messages in this thread | | | Date | Fri, 11 Apr 2003 15:43:12 -0700 | From | Steven Dake <> | Subject | Re: [ANNOUNCE] udev 0.1 release |
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Lars Marowsky-Bree wrote:
>On 2003-04-11T15:30:21, > Steven Dake <sdake@mvista.com> said: > > > >>There is no "spec" that states this is a requirement, however, telecom >>customers require the elapsed time from the time they request the disk >>to be used, to the disk being usable by the operating system to be 20 msec. >> >> > >Heh. Yes, I've read that spec, and some of it involves some good crack smoking >;-) The current Linux scheduler will make that rather hard for you, you'll >need hard realtime for such guarantees. > Its quite easy to do if you are not dependent upon spawning an entire process to execute the insertion and creation even of the device node.
> > > >>Its even more helpful for their applications if the call that hotswap >>inserts blocks until the device is actually ready to use and available >>in the filesystem. Another requirement of any system that attempts to >>replace devfs would be this capability (vs constantly checking for the >>device in the filesystem). >> >> > >Uh. Can you please clarify? > >You want open(/dev/not_there_yet) to block until /dev/not_there_yet is >inserted? But if it is not inserted, the device file does not exist yet, so >the open() will simply return a ENOENT. > >The application (or a library, providing this capability you want) could >interact with the hotplug subsystem to be notified when this device is >inserted. > > >Sincerely, > Lars Marowsky-Brée <lmb@suse.de> > > >
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