I can assure you that Solaris 10 does not have some bizarre 255 limitation on process file descriptors, at least that's not what I've experienced, having used many Solaris 10 systems over the years. Besides, no modern Unix vendor could survive with such a ridiculous limit. It therefore appears that you have a broken Solaris 10 system and that your 255 file handle "limitation" can be fixed with proper Solaris 10 system administration. Based on a random Solaris 10 google, you seem to be doing the right thing with /etc/system. I am not a Solaris sysadmin though, so I suggest you ask Sun for technical support and/or ask for help on a Solaris 10 system administration forum. I hope it's not something silly like having to reboot and/or login/logout before the new file descriptor limit takes effect.