Welcome to the second installment in the Be Your Own IT series, All About Central Processing Units and How They Work. In the first part of this series, we talked about what a CPU is, other names for it, and the different aspects and features that go into making a CPU what it is. In this, part 2 of our series, we are going to take a little more in depth look at those features to help you understand your chip even more.

Everyone wants a very fast CPU, and it is true that the faster your CPU is, the more efficient your computer system will tend to be, but there is a lot more to it. If you ha

ve the fastest central processing unit available on the market, but the rest of the components and parts found in your computer system are not as elite, then your central processing unit can only perform as well as the slowest component it has to work with. In other words, if your other components cannot perform as fast as the CPU can, the CPU will stop and wait around for them to catch up.

 

Your central processing unit has a lot of different jobs to perform in order to be able to tell your computer what to do. It “speaks” in a language called “assembly language,” and based on the instructions it gives to the computer, the processor does its different jobs. The three most basic jobs your CPU does include:

 

• Making decisions and then jumping to a new set of instructions to follow, based on those decisions.
• Moving data from one memory location over to another memory location
• And using its arithmetic and logic unit (ALU) to perform the necessary mathematical operations that your computer requires, from simple subtraction, addition, multiplication and division, to more complicated and sophisticated mathematical operations, depending on the speed and quality of the central processing unit in question.

 

A microprocessor has many things going for it. You will find it has a reset line, a clock line, a read line, a write line, a data bus and an address bus, among other things. The reset line is something that resets the program counter back to zero (or whatever the base is) and restarts the execution of a task. The clock line puts the operations in sequential order for the processor. The address bus sends an address to memory, and the data bus sends data to memory as well as receives data back from memory. The read line tells the processor to get information (read it), and the write line tells the processor to set new information, from a particular address.

 

In addition to those lines, there are many more lines found that tell your central processing unit what to do. The lines generally connect to your computer system's RAM or ROM memory, and often connect to both at the same time. ROM stands for read only memory and is programmed with a permanent set of pre-set bytes, so the address bus therefore tells the ROM chip which byte to get and also tells it to put the byte on the data bus. RAM stands for random access memory, and the CPU writes lines to it in much the same way as it does with the ROM. There is one difference, though – RAM chips delete or purge whatever information has been written to them whenever you power down your computer system, so it will then be gone, and that's what makes ROM necessary – ROM does not “forget.”

 

The ROM in your PC is called the BIOS – the Basic Input Output System. When you boot up the computer, the processor begins by executing the instructions it finds in the BIOS, which determines things like the boot sequence and runs hardware checks and more.