Many things

Actually, significantly less portable in someways; for example, a PDF is far more likely to be a binary file rather than a text file (as compared to a PostScript file). While I haven't looked into it in enough detail to be sure, I suspect that PDF is a rather emasculated subset of PostScript - that it's PS subsetted down to the point where it's no longer a general-purpose programming language with a heavy page-description slant, but rather a page-description language that cannot be used for general-purpose programming. Indeed, it would almost have to be for random access to the pages of a document to be possible. Deciding whether a given piece of PostScript code (such as the "showpage" that prints a page) is executed is, except for interpreter limits, equivalent to the halting problem - and in particular can, in principle, depend on everything earlier in the file. /~\ The ASCII der Mouse \ / Ribbon Campaign X Against HTML mouse(a)rodents.montreal.qc.ca / \ Email! 7D C8 61 52 5D E7 2D 39 4E F1 31 3E E8 B3 27 4B