They must make do with one of the standard visualization packages, which tend to be neon-cubistic, simple, and boring. This kind of software is used because it is easy to learn and use and cheap in terms of the processing power and memory needed to run it. For the examples in these rules, we will use Wiley J Bastard, a Warlock of no particular note. His Plane consists of a flat marsh, covered in waist-high reeds and surrounded by hills representing the various satellites. When necessary, leaves floating in the streams show the actual files.
Most programs show up as insects of various sorts, moving leaves around.
Larger ones appear as water creatures such as fish and frogs. But we want these examples to be simple. Those with legitimate reasons for doing this usually need only the Professional Skill Computer Operations, and skills appropriate to the software they wish to create. These people are not relevent to these rules. This skill allows the Warlock to buy any levels in OP operations that his heart desires.