Serial device: is there any way to KEEP the permissions set to 777

[Kerri Hallbeck]

HI. We have the following problem and I'm sure that there is a simple command that we don't know to use.
So, any help is appreciated.
We are trying to download information from a program to a board through a serial port and JTAG device. Our problem seems to be the serial port.
It has these permissions:
crw--w--w- 1 root bin 1 0x000000 Feb 21 10:01 /dev/tty0p0

So, as root, we change those permissions and we can then, with a simple terminal, talk to the board.
BUT we then try to download a design to the board and the permissions change to the crw--w--w- again, and the download fails.

Q: is there any way to KEEP the permissions set to 777?

or is it something else completely?

Thank you for any and all help.

Kerri

[Kerri Hallbeck]

oops, sorry, I'm using a HP Visualize J5600 and running HPUX 11.0
Kerri

[Andreas Voss · Accepted solution]

Hi,

the reset of the device permission is generated from the getty. If you never use the port as a login port you could disable the getty procees in /etc/inittab.
Change at the getty line the parameter respawn to off, save /etc/inittab and run init q.
Now you can chmod 666 /dev/tty0p0 and will be save.

Other way is to duplicate the device file ie:
cd /dev
tar cf - tty0p0 |(cd /tmp;tar xvf -)
mv /tmp/tty0p0 /dev/tty0p0_2
chmod 666 /dev/tty0p0_2
Then you have to change the device file configuration at your application to /dev/tty0p0_2

Regards