1. Stopping the data acquisition while working on the GC.
1. Go to the rungc shell screen and hit CTRL-C.  This window may disappear.  What this does is stops the continuos run cycle.
2. Now go to the "chrom" screen enter the quit command (type quit).  This will stop the current injection and set the GC to a safe position.
2. Stopping the data acquisition while connected remotely.
1. You first need to stop the rungc script.  To do this you need to determine the process id number (PIN) of rungc.  To do this simply run ps, the PIN is the first number in the row for rungc.
2. Next kill this process by typing "kill PIN".  Where PIN is the PIN number you looked up in step 1.
3. Now enter "stealthdoit stop" this will stop the current injection and set the GC to a safe position.

1. If your account is set up as a node administrator or you are a super user you can type "reboot" from a shell.  The program reboot will gracefully shut down other processes and restart the system.  The reboot program can also be executed via a telnet connection.
2. The second method is to press SHIFT-CTRL-ALT-DEL (the DEL key on the number pad).  This four key combination will also gracefully shut down other processes and restart the system.

What happens during a reboot?

1. QNX starts up operating system and TCP/IP drivers.
2. A watch dog program is started to monitor operating system crashes.
3. The computer clock time is set with a local time server and a cron script is launched to set the clock once a day.
4. The httpd deamon is launched to handle World Wide Web requests.
5. It then logs on as user stealth.
6. The file /home/stealth/windows/olwm.init is then executed which tells the computer to start rungc.
7. The system is now running in a continuous cycle mode.

With any problem, we recommend rebooting the computer first.  If the problem persists, here is a SIMPLE flow chart.

Is it a software problem?
• Is it a QNX problem?
Operating system problems can be one of the more serious problems encountered and can require extensive knowledge of the system.  Some of the problems may be fixed remotely from Boulder.  If the system reports corrupted files, it's probably best to replace the computer with the backup system.
• Is it a CATS(formerly know as STEALTH) data acquisition problem?
Maybe one (or more) of the data acquisition programs are corrupted.  Try to recompile the source code.  If this doesn't work, replace the computer with the backup system.
 
Is it a hardware problem?
• Is it the gas chromatograph?
Maybe we have some spare parts.
• Is it a communications problem?
This could be a problem in either the GC or the computer.  Try to determine if ALL data (analog and chromatographic) data is not appearing.  If this is the case, the Metrabyte card (in the computer) could be dead.  Try switching to the backup computer.  If this doesn't work, one of the GC pc boards may be dead.