> --- Dan Erickson <coldoneknight@rogers.com> wrote: > > > And he said a userspace program sends the command. > > Is this true? Yes it is. IOCTL is strictly a medium of communication of userspace programs to talk to kernelspace devices. Most of the functionality of drivers are generally wrapped up in abstractions like VFS etc. But sometimes there are those specific commands that you want to send to the driver which are not covered by these abstractions. In those case you use IOCTLs to send thos specific commands. As Rubini mentions it, IOCTL is the "garbage bag of all communication with kernel space" i.e. all functionality you can't have otherwise, you make it happen through IOCTLs. > > What I mean, is that something needs to say "I want > > to keep the computer > > alive". So I will call WDIOC_KEEPALIVE to do this > > for me. And it was > > highly confussing me as to what actualy sends the > > WDIOC_KEEPALIVE to the > > driver. So you have a userspace daemon calling this IOCTL to the driver to keep it alive. Note: If you are asking this with regards to the watchdog thing, I am not sure how a watchdog works, so I might actually confuse you further. ;) - Sandip -- Sandip Bhattacharya Mindframe Software Work: sandip @ mindsw.com, http://www.mindsw.com Play: sandipb @ bigfoot.com, http://www.sandipb.net ----------------------------------------------- -- Kernelnewbies: Help each other learn about the Linux kernel. Archive: http://mail.nl.linux.org/kernelnewbies/ FAQ: http://kernelnewbies.org/faq/
