Tivo Hacks. 100 Industrial-strength Tips Tools 2003

7.1 Hacks #88-100

We've run the gamut of the kinds of tips, tricks, and hacks it takes to become a TiVo power user , but we haven't taught you to build anything yourself yet. Up to this point, the extent to which you've hacked your TiVo's software has only meant borrowing and running other people's code.

Let's change that.

While this chapter will not magically turn you into a TiVo code jockey, it will whet your appetite, providing a reasonable primer on the concepts you'll need to understand if you're going to start stringing together pieces of code to suit your purposes. To sit at the feet of the masters, hang out at some of the user forums, such as http://alt.org/forum, devoted to open source TiVo development. Be forewarned, though, that most contributors there are pretty advanced. But that shouldn't stop you from listening in and learning.

As is usually the case with hacking, there's more than one way to do just about everything. There are two programming languages on TiVo you usually stumble over:

Tcl

Tcl (pronounced " tickle ") is the glue language of the TiVo world, passing commands between interactive applications, and providing a lower learning and development curve to building lightweight TiVo applications.

C

C performs much of the heavy lifting in TiVo. TiVo's main brains (read: binaries) are written in C. C is harder to write correctly, but it's compiled for speed and let's you do so much more in terms of interfacing with the TiVo hardware.

Which language you choose is for you to decide, depending on the task at hand, balancing rapid versus more stringent development, and taking into account your level of programming skill.

To write Tcl, all you really need is a text editor Section 3.11 on your TiVo, or you can edit on your PC and FTP[Hack #55] the files across, or use a shared NFS directory[Hack #56]. Once set up to write the code, run your creations from the command line using the onboard Tcl interpreter.

C code needs to be compiled before it'll run. It's generally not a good idea to run the compiler on your TiVo itself, because the horsepower drained will seriously affect the operation of the box: video stutters, menus become unresponsive , and so forth. Think of it like running the MP3 player [Hack #46], but worse . Instead, get your hands on a cross-compiler [Hack #100] that, while it runs on another computer, generates executables that run on the TiVo platform. At http://tivoutils. sourceforge .net/, you'll find cross-compilers for x86, Mac OS X, and some that run natively on the TiVo.