Re: OOC6: Because
Hacking uses the Computer skill almost exclusively.
If you're just doing research, I figure out the TN and the number of successes tells me how much you learn.
For hacking, I try to keep it to basically a 'realistic' network architecture, but network features are represented by whatever the VR metaphor the system uses. So a file store looks like a library perhaps and you'd search for a particular 'book' to find that file.
Matrix only has a limited set of actions. They each fall into a category (so reading files falls into the FILE category). The categories are Access, Control, Index, File, and Slave, or ACIFS. The matrix system defines the basic difficulty (TN) for each of those ACIFS. The programs you have on your deck reduce those TNs. So a super-skilled decker can run without programs, but he'll be rolling against TNs of 9 or 10. Programs bring those TNs down to something more reasonable.
The system has defenses located in different places. They also almost always have an Intrusion Detection System (IDS), which notes suspicious activities. Every time your hacker does anything, the host rolls against your Masking rating. The number of successes is added to the security tally. As the tally goes up, it tells the host that it may be under attack and it begins activating more defenses.
Hosts also have a general rating, for instance Green-4 or Red-9. The number indicates how twitchy it is (how sensitive the IDS is), the color how deadly the host's defenses are.
I think that sums it up in a nut shell :)