Portable computers may be divided into different categories. This is a subjective decision, but I try to do so. My groupings roughly follow the generally accepted marketing categories. The criteria could be:
Weight: Often expressed in terms like Portables, Laptops/Notebooks, Sub/Mini-Notebooks, Palmtops/PDAs. There is no standard method to define the weight of a laptop, therefore the data provided by the manufacturers (and which are given below) have to be considered as approximations. The question is how the power supply (whether external or internal) or swappable parts like CD and floppy drive, are included in the weight.
Most peripheral cables are appallingly heavy. If you get a subnotebook and carry it around with a bunch of external drives, cables, and port expander dongles and power converter, you may be lugging a heavier bag than if it were all in one box. Subnotebooks are useful mainly if you can afford to leave all the other junk behind.
Supported Operations Systems: proprietary versus open
Price: NoName versus Brand
Hardware Features: display size, harddisk size, CPU speed, battery type, etc.
Linux Support: graphic chip, sound card, infrared controller (IrDA®), internal modem, etc.