Giving examples, make detailed notes explaining the function of the system unit components and how they communicate. These notes are to be included in your blog.
The system unit is the actual computer; everything else is called a peripheral device. Your computer's system unit probably has at least one floppy disk and drive, one CD or DVD drive, into which you can insert floppy disks and CDs. There's another disk drive, called the hard disk inside the system unit, as shown in the following diagram.
You can't remove that disk, or even see it. But it's there. And everything that's currently "in your computer" is actually stored on that hard disk. (Because there is no place else inside the computer where you can store information.
Random Access Memory (RAM)
There's too much "stuff" on your computer's hard disk to use it all at the same time. During the average session sitting at the computer, you'll probably use only a small amount of all that's available. The stuff you're working with at any given moment is stored in random access memory (often abbreviated RAM, and often called simply "memory"). The advantage using RAM to store whatever you're working on at the moment is that RAM is very fast. Much faster than any disk. For you, "fast" translates to less time waiting and more time being productive. So if RAM is so fast, why not put everything in it? Why have a hard disk at all? The answer to that lies in the fact that RAM is volatile. As soon as the computer is shut off, whether intentionally or by an accidental power outage, every thing in RAM disappears, just as quickly as a light bulb goes out when the plug is pulled. So you don't want to rely on RAM to hold everything. A disk, on the other hand, holds its information whether the power is on or off.
The Hard Disk
All of the information that's "in your computer", so to speak, is stored on your computer's hard disk. You never see that actual hard disk because it's sealed inside a special housing and needs to stay that way. Unlike RAM, which is volatile, the hard disk can hold information forever with or without electricity. Most modern hard disks have tens of billions of bytes of storage space on them. Also you can create folders save pictures videos or download software and the data can stay store for months or years without using up all the storage space it provides.
Like the mouse, the keyboard is a means of interacting with your computer. You really only need to use the keyboard when you're typing text. Most of the keys on the keyboard are laid out like the keys on a typewriter.