sentences:  Accessing the hard disk drive is complex and time-consuming, involving partial disassembly of the unit and the removal of over 30 different-sized screws.The memory in the iBook G4 is covered by a removable Airport card, and accessible by removing the RAM shield with a Phillips#00 screwdriver.While some of the earlier models (e.g., 800 MHz and 933 MHz) have a specified 640 MB RAM limit, it is possible to have a total of 1.12 GB of RAM installed (128 MB built-in, plus a 1 GB SO-DIMM), or 1.25 or 1.5 GB in the later models with 256 or 512 MB of RAM soldered to the logic board.