/-Root-FS: Readonly?

Hi, I'm setting up a firewall with 6.4. At the moment, I'm trying to secure the machine. I wanted to set the /-FS to readonly, only /home,/var,/tmp are writable. All works fine, but after closing a tty, mingetty is respawning too fast and I'm unable to use this tty any more. I tracked the problem down to an write-attempt to the cua-device, but the system reports that / is mounted readonly. Is there a possibility to supress this write-access in the respawning-process? -- Stefan Bauer