2. Invoking DetCom

Observing accounts should typically be set up by the site administrator so that DetCom is already running in a window. The observer should not invoke detcom themselves if it happens automatically when they log in.

To be fully functional, DetCom requires two other components:

1. The special command shell called Director.
2. A color-capable terminal window ( rxvt and xterm work on most modern unix systems.)

The first step is to launch an rxvt, which can be done automatically from the user's .xsession (in Sidious Linux, the file to look in is .fvwm-initfunction in the user's home directory.) This file must be executable (run chmod +x .fvwm-initfunction to be sure) and contains a line such as this:

rxvt -e director &

Director, in turn, reads a startup file, ~/.director/startup which should contain instructions to start detcom. A simple line such as:

# .director/startup - Startup commands for director shell.
agent start detcom

would cause DetCom to be started using the last known DSP code (which it saves in .detcomrc). This command can also be typed manually at the prompt in the director window.

2.1 DSP Code Selection

Rather than relying on .detcomrc to control which DSP code is loaded, most sites prefer to use the startup file to control which DSP code will be loaded. In this case, the DSP code filenames are listed on the ``agent start'' line which invokes detcom and any boot commands from .detcomrc are ignored. All other commands from .detcomrc are still processed normally. A startup file that controls which DSP code is loaded would look like this:

# .director/startup - Startup commands for director shell.
# Uncomment ONE of the following.  Restart director or type the
# command ``source ~/.director/startup'' in the director window
# after changing this file.

#agent start detcom some_ltb.lod some_lub.lod
agent start detcom other_ltb.lod other_lub.lod

Finally, the ``boot'' command can also be used to quickly switch from one DSP code to another (but engineering mode must be active.)

2.2 Which DSP code is loaded?

Regardless of the method used to boot the DSPs, the currently active code can be seen on ``info'' lines 8 and 9. If they are not visible (below the director prompt), issue the command ``infosize 9'' to reveal them. The command ``boot status'' will also display the same information. For example:

> boot status
ltb: /home/ccd/DSP/psu4k/psu4kltb/psu4kltb_a.lod(#185) OK, 379 symbols.
lub: /home/ccd/DSP/detcom/detcomlub/detcomlub.lod(#57) OK, 276 symbols.

The numbers in parentheses are the serial numbers which are incremented by the Makefile each time a .lod file is rebuilt.