Saturday, February 06, 2010

What is Memory in my Computer?

There is much confusion over the meaning of all numbers associated with our computers. I touched on some of this when I wrote about the Task Manger a few blogs ago.

What are all those Mb’s and Gb’s all about?

When you go to the local store or surf the net looking for a good deal, each computer has numbers like the following:

2 GB memory, 160 GB hard disk, 2.4 GHz processor

First, let us review the terms. Mb is megabyte, GB is gigabyte, TB is terabyte, and GHz is gigahertz. Mb or megabyte refers to 1 million bytes and a byte in simple terms is how much storage is needed to store on character of data. GB means gigabyte and refers to 1,000 MBs. TB is terabyte and refers to 1,000 GB’s. GHz is gigahertz and is measurement of speed. Years ago this was referred to a gigacycles.

The memory even if not mentioned as such is that number from 1 GB -8 GB. This refers to the amount of RAM or random access memory in the box. RAM is primary storage. This is a key number as far as speed and the number of applications that can be open at the same time. More on this later.

The 80GB – 1TB number indicates the amount of hard disk space available in the box. This is not primary storage, but rather secondary storage. This is where all your applications including the operating system (Windows XP, Vista, or 7) is stored. It is where you save all your personal documents and pictures and songs and movies. The bigger the drive, the more stuff you can accumulate.

I can remember back in the 1980’s when I would tell customer they would never need more than a 10 Mb disk drive to store all their stuff. When Windows came along that number was not even large enough for the operating system never mind pictures and movies.

How much do we need today depends on what you are planning on storing locally. If you are not into digital pictures or downloading movies, 80 GB should be more than enough for the foreseeable future.

The GHz value indicates the speed of the CPU or central processing unit—the brain of your computer which is located inside the box on the motherboard (also known as the system board). Older machine ran at 400-600 GHz and the newer ones are much faster. Suffice to say, the bigger the number the faster your computer can process data. Yes this affects the speed of your Internet surfing.

How you find out the speed of your computer and how much RAM you have is simple. Hold down the Windows key (the flag key left and or right of your spacebar) and tap the Pause key (usually top right on the keyboard). This brings up the Systems Properties window. Under the General tab locate the Computer section. It tells you the name of the CPU, how fast it is, and how much RAM is installed.  To find out the size of your disk drive hold down the Windows key and tap E. This opens the My Computer window. Locate the C: drive and mouse over the icon. The Total Size value displays along with the amount of free (or available to be used) space left.

Back to RAM.  It is primary storage and is used by the CPU to access and run your applications and work on your data. It is volatile. When the power is turned off, the contents of RAM goes away. This is why we have secondary storage devices like the hard drive, CD/DVD drives, and USB flash drives. Those devices are used to save what we have been working on so we can access it again later.

When you turn on your computer the operating system is copied from the disk drive to RAM. You see a Windows GUI (graphical user interface) and select an application to use. Let’s say you choose Microsoft Word. That application is added to RAM and you see the interface for Word so you can type a letter. What you type is added to RAM. When you save your letter, a file called a document in Word, is created and placed in secondary storage on your hard disk drive. Even what you save on the desktop is placed on the hard disk drive.

Think of a chalkboard as RAM. As your write on the board it is like writing a letter in Word. You can write until you fill the board. When you are done, you erase the board (like closing the program). Now you can draw a picture as if you were in the Paint program. The chalkboard is the RAM that is temporarily storing your data. Need more RAM? Then you have to get a larger the chalkboard.

The more applications you have open as noted by the number of items on the task bar—that horizontal list of application on the bottom of your desktop, the more of RAM is used. When the amount of RAM in use is close to the physical memory available, you see a message saying you are running out of memory. This does NOT mean you need more hard disk space. It means you must close some programs. However, due to some issues with certain applications, you may want to restart the computer to free up the maximum amount of RAM.

Computer running slow?

Check the amount of RAM you have and the amount free disk space. Adding RAM is usually easy, but on older machines there is a maximum amount determined by the number of slots on specifications of the motherboard. The more RAM the better.

If the disk drive free space is not 10% of the total size of the drive, you could begin to slow down. Run the Disk Cleanup program under Start > Accessories > System Tools to clean out unnecessary files.

Replacing the hard drive can be a challenge. It is easier to purchase an external hard drive that plugs into a USB port. Transfer all your pictures and movies to it. This will free up plenty of space and leave the files accessible when you need them.

Other reasons for a slow computer have to do with ad-ware and malware you may have picked up even with a current security program. More at another time on how I deal with these issues.