We have a file and print server Dell PowerEdge 840 that has been running for just about a month. The OS is RedHat Enterprise Linux ES 4. It serves 6 PC's running Windows 2000 or XP Pro. The printer is an HP LaserJet 5100. It's locally-connected, connected to the server through a EPP/ECP parallel port on an PCI card. Parallel port modules are installed/loaded as shown by lsmod command.

It's been twice happened that the print service (suddenly) hung after days the server running well as both file and print server. At such that time, the server kept receiving printing requests, and listed them in the queue (as can be seen using lp command), but the printer just sit there doing nothing as if there was no request from the server to do something. The problem was fixed by rebooting the server. After the rebooting, the server resumed the printing service, i.e. printed all those queued print jobs that were there before the rebooting.

We would like to have a better solution than rebooting the computer, the ultimate one is preventing the problem from happening. Please help, any clue or solution would be appreciated. Thank you.