That depends on the licensing of the software in question. Some applications will only permit you to install on a single computer, while others permit multiple or indefinite numbers of computers. Very few make any restrictions about the number of CPUs you can have in your computer.
They are treated exactly like two separate CPUs. Any operating system that can use multiple CPUs can also use a processor with multiple internal cores, with no changes needed to the code.
The central processing unit (CPU). In the past, CPUs used to only have 1 core, but with the multiple cores in computers now, it is like having multiple CPUs.
Too many to even begin to list here, forget describing the architectures.
64-bit
When CPUs first started coming out, and for many years after, they could only execute one set of instructions at a time. After awhile, interfaces were built to support having multiple CPUs running at the same time to increase the horsepower of a machine. These CPUs had distinct packaging still, but now the computer as a whole could execute a set of instructions per CPU. CPU manufacturers started placing multiple CPUs in one distinct package and also included the interface for the CPUs to talk within this package. So even though you had one product, it could execute multiple instructions at one time. Core is a marketing term to let people know the number of independent sets of instructions that a single CPU package can execute.
Windows XP supports multiple CPUs out of the box. No further adjustment is needed.
A Web application running on a single server that has multiple CPUs is called a Web Garden
A multi-core processor is one which combines what are essentially multiple CPUs into a single chip. As far as the operating system and other software are concerned, it is the same as a dual or quad-cpu computer system, even though the cpus are physically one single unit.
Yes, although to use multi-programming effectively your hardware needs to have multiple CPUs.
One of the better places to view CPU benchmarks is on Passmark. It is good for comparing CPUs, both by performance and by price. They also have trial software you can download to see how your computer compares. If you want to use it past the trial, you have to purchase it.
It depends on the motherboard. There are some that allow you to run two CPUs, but you can't buy any old motherboard and shove two processors in there. I'd recommend just getting a dual, quad, or sextuple core CPU because having multiple CPUs doesn't up speed, it is like having a dual core processor. Not all programs can use multiple cores, so it is, in my opinion, much better to just get 1 multi-core CPU than to get multiple CPUs.
Symmetic multiprocessing is about having multiple CPUs. It is an architecture or design rather than a device.