Memory between zero and 640Kb. This area of memory is used to store programs when they are being run, together with device drivers and data. It is the main area of memory that is fitted in all PCs.
However, because it's not really enough for the big software applications that are used today, most PCs are fitted with more memory (also called RAM). A standard PC would be fitted with 4Mb: the first 640Kb is still called the conventional memory, the next 384Kb is called upper memory and the remaining 3Mb is called extended memory. You don't need to worry about how the memory is used. If you're using Windows 3.x there's a utility called MEMMAKER that will sort out your memory and make sure that it is working at its best. For Windows 95 users, it's all done automatically.
