Threads

“In computer programming, a thread is an instance of a sequence of code that is operating as a unit, typically on behalf of a single user, transaction, or message. Threads are sometimes described in terms of their weight, meaning how much contextual information must be saved for a given thread so that it can be referred to by the system during the life of the thread.

For example, the context of a UNIX process includes the hardware register, the kernel stack, user-level stack, and so on. The time required to switch that much context, in thousands of microseconds, is considered large, so a UNIX process is said to be a heavyweight thread.

In some modern operating system kernels, such as Mach, multiple threads can exist in a single address space, which decreases the amount of context that must be saved with each one, and reduces the switching time to hundreds of microseconds. These kernel-level threads are considered to be middleweight threads. When all context and thread operations are exposed at the user level, each application needs only the minimal amount of context saved with it, so that context switching can be reduced to tens of microseconds. Therefore, user-level threads are considered lightweight threads.”

Definition of Threads above was found at whatis.com. A very cool site, check it out. Lets move onto Hyper-Threading-Basic Explanation

Hyper-Threading enables one CPU to perform somewhat like a multiple processor configuration (SMT). This technology was implemented on Intel’s server CPU’s and is now finally coming to the desktop market. 

Most CPU’s can only execute a single thread at a time. If you have a dual CPU computer you can execute two threads at a time thus improving performance, especially with programs that have multiple threads. Can you afford a dual processor machine? I can’t, and this is why Hyper-Threading is so cool. Not many people can afford this type of performance, but the new Intel desktop CPU’s will provide a solution to this problem. It’s somewhat like having the power of two CPUs. Hyper-Threading is actually present in all of Intel’s Pentium 4 CPU’s; it’s just been turned off. All Intel is really doing is turning it on and letting out the power. Although some software applications will benefit greatly from this technology, the question remains, will the mainstream software companies support Hyper-Threading and optimize their programs to utilize it? We sure hope so.