Jodrell computing

Useful hints when constructing computer programs at Jodrell:

• Files in /usr/local/{bin,include,lib} were put there by the operating system, and are not updated. Try to use ones in /usr/{bin,include,lib} instead, as these are updated every so often.
• valgrind is useful for finding problems with memory, which may give odd error messages. See [1] for how to use it.
• If you're running a job that will take a long time, prepend the command to run it with "nice +19", e.g. "nice +19 ./virtual_sky", so that others can use the computer too. This is especially important when running on someone's desk computer, rather than on a server.