Processor Sockets and Slots 
Describes socket and slot standards and other issues related to mating processors to the system motherboard. This page is from "The PC Guide."

HardwareCentral: Memory Packaging
In the old days, these chips were either soldered onto the motherboard or placed in special sockets. Unfortunately, this meant that when a memory chip went bad, you had to replace the whole motherboard. With socketed chips, chip creep became the problem.