What happened to the remaining 5.7MB of memory? How is the rest of my LaserWriter Pro 630's memory allocated?
Since legal-size (8.5 by 14 inches) is the largest available page size, the memory required for a legal-sized page can be calculated by multiplying the total imageable area (8.5 by 14) by the highest vertical and horizontal resolution in dots-per-inch (600 by 600). This calculation comes out to roughly 5MB.
The 2.3MB of "free" memory is used for such things as the PostScript interpreter itself, PostScript dictionaries, display list, font caching, and program memory.