From mboxrd@z Thu Jan 1 00:00:00 1970 From: dave@horsfall.org (Dave Horsfall) Date: Wed, 7 Feb 2018 16:39:08 +1100 (EST) Subject: [TUHS] Device special files In-Reply-To: <20180207021405.CF19B156E812@mail.bitblocks.com> References: <1517946499.3717582.1261737872.3DC598F2@webmail.messagingengine.com> <20180207012556.GL30690@eureka.lemis.com> <20180207021405.CF19B156E812@mail.bitblocks.com> Message-ID: On Tue, 6 Feb 2018, Bakul Shah wrote: >> Wasn't that "devfs" (which Penguin/OS calls "udev")? I've never >> grokked that concept. > > In the old days where a limited types of devices were > available for a particular kind of machine, they could be > statically assigned a major dev number (matching their index > in the {b,c}devsw table). To make them accessible to users you > did > > mknod [...] Umm, I've known that since Edition 5; I'm not exactly new to Unix, you know... [...] > So the point of devfs is to avoid having to do mknod manually and yet > provide access to all found devices from the userland. As a side effect > you can also use it for programs that run in their own sandbox or for > jails and require access to a device. That makes sense; bit of a pain when a USB device suddenly disappears just I unplugged it, though... -- Dave Horsfall DTM (VK2KFU) "Those who don't understand security will suffer."