In the first two installments in this series on what computer memory is, what it does, and how it works, we talked about the basics – such as the various types of computer memory you are likely to encounter in a day, the most typical types of computer memory you will find on a typical computer system, and why your computer requires different types of memory to run.

You may be a little fuzzy on the exact mechanics of all of that memory, though, and if you are, we don't blame you. Since one of the main reasons that your computer requires all of those different types of memory to

run is that all of our computers would otherwise be prohibitively expensive if they only used the most efficient, and also most costly, type of computer memory available, each of the different types of memory that are found in a typical computer system have a different task to perform and a different time to jump in and do their jobs.

 

The following is a step by step outline of what happens when you boot up your PC and run some applications, from beginning to end. By reading this carefully, you will be able to see not only exactly what your computer is up to when you ask it to perform certain tasks, but also see where the different types of memory in your computer system come into play.

 

1.)  You turn your PC on and begin the boot process.

2.)  Your computer system then immediately begins to load data from a type of memory called Read Only Memory (ROM), and then performs a test called a “power on self test” to check and make sure that all of the major components in your computer system – motherboard, RAM, CPU, etc – are functioning correctly and as normal. The power on self test is also called POST. When you hear the small beeping sound at start up, that is your POST happening.

3.)  During the POST process, a part called the memory controller proceeds to check all of the memory addresses in your system with a really quick read/write operation, where data is written to a bit and then read again from that same bit. This is done to ensure that there are no errors in your memory chips.

4.)  Once that is completed, then your computer proceeds to load the “basic input output system” from the ROM. The “basic input output system” is also known by the shorter and easier to remember name of “the BIOS.” Your system's BIOS provides the basic information about the boot sequence, security, storage devices, plug and play capability and a few more similar items.

5.)  After this, your computer loads your operating system from the hard drive into the system's RAM. The critical parts of your OS are maintained in the RAM for the entire time your computer is on, which allows the CPU to have immediate access to the OS, making it run faster and better for you.

6.)  After this, you can open another program, which will then be loaded into RAM. To conserve RAM use, many of the programs that you use only load the most important parts of the program at first, and then only load other pieces as necessary. Any files that are opened for use with this program will also be loaded into RAM.

7.)  When you then proceed to close that program after saving your work, the file will be written to a specified long term storage area and then the data in RAM is deleted to make room for the next program or application.

 

And that is what happens when you boot your computer up every time! Stay tuned for the next installment in this series packed with information about that all important computer memory and how it works.