Casting the runes is the process a guru does when you ask him or her to run a particular program and type at it because it never works for anyone else; esp. used when nobody can ever see what the guru is doing different from what J. Random Luser does. Compare incantation, runes, examining the entrails.

A correspondent from England tells us that one of ICL's most talented systems designers used to be called out occasionally to service machines which the field circus had given up on. Since he knew the design inside out, he could often find faults simply by listening to a quick outline of the symptoms. He used to play on this by going to some site where the field circus had just spent the last two weeks solid trying to find a fault, and spreading a diagram of the system out on a table top. He'd then shake some chicken bones and cast them over the diagram, peer at the bones intently for a minute, and then tell them that a certain module needed replacing. The system would start working again immediately upon the replacement.

References

Jargon File 2.4.2