[ale] MyStEriouS FilE

[Eric Z. Ayers]

Hello Ryan,

ryanbridges at mindspring.com writes:
 > 
 > Just as a semi-random guess, perhaps it has something to do with the
 > initial console device?  ioctls are widely undocumented but they are used
 > with device files.  Not sure what makes me think it is related to the
 > console.  My brain gets confused this early in the morning:)
 > 
 > --Ryan-- 
 > 
 > On Tue, 3 Aug 1999, Eric Z. Ayers wrote:
 > 
 > > 
 > > Now that I have your attention, does anyone have a clue what the file
 > > /etc/ioctl.save is, and which programs use it?  
 > > 

That answer is good for 2 marks!

One of the crack members of the sysadmin team here at the office found
a pointer in /usr/src/linux/Documentation/serial-console.txt 

...
4. Init and /etc/ioctl.save

   Sysvinit remembers its stty settings in a file in /etc, called
   `/etc/ioctl.save'. REMOVE THIS FILE before using the serial
   console for the first time, because otherwise init will probably
   set the baudrate to 38400 (baudrate of the virtual console).

...

and thus we looked at 'man init':

       ...

       When entering single user mode, init reads  the  console's
       ioctl(2)  states  from  /etc/ioctl.save. If this file does
       not exist, init initializes the line at 9600 baud and with
       CLOCAL  settings.   When  init leaves single user mode, it
       stores the console's ioctl settings in this file so it can
       re-use them for the next single-user session.