computers

A Layman's Guide To a Computer's CPU
The Central Processing Unit

The CPU of a computer is the main lynchpin of the computer system. Without it, nothing happens. It is a small slab of silicone about 10mm (3/8ths of an inch) square and about 2mm thick, which has been etched and doped microscopically to form circuits, switches, transistors and other electronic components: hundreds of millions of these components are embedded in this tiny space. The rest of the physical size of the CPU is taken up by little connecting wires from these circuits to the 100 plus pins on the underside of the CPU chip, a couple of external components, and with heat transfer fins and fans which are needed to cool that little slab of silicone, which is doing 2800 million operations per second! (That's for an average off the shelf 2.8GHz computer)
The CPU is mainly a calculating unit, and can do complex arithmetic functions. But the CPU is actually made up of a number of distinct modules with different functions, like ultrafast short term storage called cache, traffic control to control the data flows, like a traffic light, and arithmetic units to do the sums.
The CPU on it's own is a dead lump of metal and glass. It needs to be fed data to be of any use. There are various other circuits in the computer that get it started up, such as the BIOS (Basic Input/Output System), and this then fires the Operating System up, which starts injecting instructions in the right format to the CPU, and then waiting for the results of the CPU's work so that this can be passed on to other circuits, like the graphics card for example, in order to display something on your screen.
A CPU's speed is measured in Megahertz or Gigahertz, ie 1 million operations per second (MHz) or 1000 million operations per second (GHz) Thus a 3.0GHZ CPU will be able to handle 3000 million operations per second. Bear in mind that a calculation or sum takes quite a large number of "operations" to complete.
CPU's sometimes get a glitch in their data feed, so that they sit waiting for the next instruction which never comes. There is a circuit built into the CPU that checks for this inactivity, and which then clears and restarts the CPU. Sometimes this also doesn't work, due to a badly written program or data corruption, and this is known as a computer "hang." Rebooting the computer starts the CPU up from scratch, and this clears the "hang" and allows normal operation again.
A CPU is normally the most expensive part of a computer, due to it's extreme complexity, research and development costs, and because a lot of the tiny internal contacts are made from gold or gold plating, and other expensive materials. The gold is used because it is one of the best conductors of electricity, and it doesn't ever tarnish or rust or corrode in any manner.
CPU's like to be kept cool, so make sure that their fan is always working and that their cooling fins are not clogged up with dust and fluff. Then this technological marvel should give you years of trouble free service.

Cleaning The Inside of Your Computer
Firstly, let's go through the steps of cleaning your computer's inside, then we'll discuss the benefits of the exercise.
TOOLS NEEDED: Star and flat screwdrivers, new 2 inch paintbrush, old toothbrush, air blower, soft damp cloth.
1. Remove any CD's, DVD's, stiffies, flash drives, etc from the drives.
2. Switch the power off and unplug the computer from the wall outlet.
3. After making a careful note of where all the plugs and cables are connected, unplug all the rear cables, and then take the computer to a table outside (or where the light is good), and where you can make a lot of dust. Using the air blower, blow the dust off the outside of the computer case, especially the back connections.
4. Take the cover(s) off the computer case. Usually there are two or more screws at the back, and then the covers slide off rearwards, but there are so many different types of cases, you may have to figure out how they come off!
5. With the air blower, start blowing from a distance of about 2 feet and gradually move closer as needed, being careful not to blow the computer components to bits. You want to remove the dust, not sandblast the thing. Pay special attention to any fans, and also to the main CPU. The main CPU should have a large finned heat sink attached to it, which becomes caked with dust.
6. Once you have blown the worst of the dust off, use the air blower and the paint brush to dust off stubborn caked dust, especially on the heat sink of the CPU, on the fan blades, and around the Power Supply Unit, which is the metal enclosed box where the mains plug goes in. Don't forget the fan at the back of the computer. Using the paintbrush you can get to the fan quite well through the inlet vents.
7. If there is any dust that is too caked to get off with the painbrush, use the old toothbrush to gently brush it off.
8. Once all the dust is gone, use the soft damp (NOT wet!) cloth to wipe down the outside of the computer case and the loose covers.
9. Put the covers back, take the computer and air blower back inside and connect all the computer's plugs up. Check that they are all correctly and firmly inserted, and then switch the computer on again.
10. Open the CD/DVD drawers and using the air blower, blow into the drawers to remove any dust that may have got into there. DVD players don't like dust on their internal lenses.
BENEFITS OF AN INTERNAL CLEANUP:
Computer CPU's (Central Processing Unit, the "brain" of the PC) generate a lot of heat, due to all the processing going on in their integrated circuits. The finned heat sink mounted on the CPU transfers heat from the CPU to the surrounding air by creating a large surface area (that's what all the "fins" are for.) If this surface area is covered with dust, it traps the heat and the CPU overheats, shortening it's life span.
In the same way, if the fan blades and inlet vents are caked with dust, this reduces the amount of air that can be sucked in to the computer and over the CPU heat sink, so the computer will run at a higher temperature than it should, which will shorten the life of the various components in the computer.
CD and DVD players are very fussy about dust. A few specks on the laser lenses can cause a lot of problems when reading and writing data, in some cases the machine will reject the disk as unreadable.
If you live in a warm climate, this should be done fairly often.
A clean computer should give you many years of trouble free service.

How To Use a Computer Mouse.

To those people who use a computer everyday, this must seem like a really unnecessary article, but to those people who are getting their first computer only because they want to be able to email their kids in Alaska, it's not such a small issue. So for all you people that are too afraid to ask this question, here are all the answers. (Hopefully your kids will print out this article for you!)

DESCRIPTION OF THE MOUSE

The mouse is a pointing device. It usually has a wire coming out of it that connects to the computer, it fits comfortably in your hand, and it usually has 2 buttons with a little wheel between them. When you press the buttons down, they make a soft clicking sound. This is known as "clicking the mouse." If you press the left button, this is known as a "left click" and clicking the other button is known as a "right click" The little wheel is known as a scroll wheel or the mouse wheel, and it also clicks if you push it down, and you can rotate it with your finger as well.

MOVEMENT OF THE MOUSE

There is a little arrow that appears on your computer screen when you start the computer up. The mouse controls this arrow. If you drag your mouse across your desk to the left, the little arrow moves to the left, move the mouse forward, and the arrow moves forward. The arrow mimics your mouse's actions.

OPERATING THE MOUSE.

Probably the first thing you will be told to do on your new computer is "click the start button." So what you do is this: drag your mouse across your desk to make the little arrow on the screen move down to the extreme left bottom corner of your screen where there is a picture of a green button with "START" written on it. When the point of the arrow is over this button, press the left hand button of the mouse. You have then just "clicked the start button!" This will cause the start button to "depress" and a menu will pop up with lots of other options that you can "click"

If you are asked to "double click" the mouse, it means that you press the left mouse button twice in quick succession about half a second apart. There are many little pictures on your computer screen called "icons." If you place your mouse pointer over one of these icons and then double click your mouse, it will open up the program associated with that icon and you can then do stuff, like compose and send emails and so on.

Right clicking the mouse often brings up a pop up menu that allows you to do extra things. For example, right clicking in an empty space on your startup screen will bring up a menu of settings to do with your display and it's appearance.

THE MOUSE WHEEL

The mouse wheel is quite a useful feature. When you are reading a long document that extends beyond the size of your viewing window, rotating the mouse wheel scrolls the document up or down so that you can continue reading it without lifting your hand off the mouse or moving it. It also works in web pages and emails, scrolling the window contents up or down. When using internet explorer to look at pages (web sites) on the internet, clicking the mouse wheel (ie. pushing the wheel down) will open a new blank tab, so that you can have 2, 3 or 8 web pages open at the same time.

SOME RELAXING EXERCISES

The best way to get used to the mouse operation is to play
games with the mouse. To get to games, click on the start
button, move your mouse pointer up to All programs, then
move it up to Games, then across to Solitaire, and then click
on Solitaire. You can then play this card game to get used
to moving and clicking the mouse, and you won't do any
damage! There are quite a bunch of other games you can try
there too.

The mouse, invented over 40 years ago, is a really helpful little
device, and once you're used to it, you will find that it becomes
like part of your arm. Enjoy it!

WHY ADDING RAM IS A GOOD THING

A very common bit of advice we all get from computer people is that if we want to speed up our computer, we should add more RAM, or Random Access Memory. This is good advice, and is usually true. But how does adding RAM achieve this?

THE RAM'S FUNCTION
When you start up your computer, it gets its initial start up instructions from the ROM, or Read Only Memory, which sets up the basic configuration of your PC and enables it to start reading your Hard Drive. After that, all the programs are read from the hard drive, and loaded into your RAM, that is, into the computer's "memory." Your Windows or Mac operating system, your word processor, your internet browser - all these things are loaded into your RAM.

Now, if your RAM is small, say 128 Megabytes, you start running into problems. The operating systems, like windows XP, will use up around 120 Megabytes. Then your Office suite of programs will use up another 100MB or so. But wait! Thats 128 + 120 = 248 Megabytes, and the computer is still able to load more programs! How is that possible?

PAGE SWOPPING
When your RAM gets full, what the computer does is that it does page swopping. This is when the computer swops blocks of memory, that aren't being used, out of memory and writes them back to the hard drive, into a special area of the hard drive called the Paging File, and it then puts the needed data into this place in the RAM that has been "cleared out."

THE PROBLEM
But here's the rub: RAM is very fast to access, but the hard drive is very (relatively) slow. So when you are running 300 or 400 Megabytes of programs in a 128 Megabyte RAM space, your poor computer is going to be frantically swopping blocks of data between your slow hard drive and your fast RAM. When you're not using your mouse, it swops all the data connected with your mouse out of RAM. When you touch your mouse again, it rushes off to get this data off the hard drive again. So the end result that you experience, is that the computer seems sluggish and unresponsive.

THE SOLUTION
Putting more RAM into your computer means that your PC no longer has to swop data between your hard drive and your computer, so all the activity takes place at the much faster RAM speed. RAM, being a solid state device (ie no moving parts whatsoever), is many hundreds of times faster than a hard drive, which has a spinning disk and magnetic pickup heads, that have to physically move to where the data is on the disk, and read it in.

THE RING ANALOGY.
Think of it this way: Let's say you like to wear rings on your fingers. When your fingers are full, if you want to wear new rings, you'll have to take off some of the ones you're wearing, and put them back in the safe, before you can don the new ones. Getting more RAM is like getting 20 or 40 more fingers to wear your rings on - so you can wear them all at once!
So the more RAM you have, the more programs and graphics you can have running at the same time without slowing your computer down.

HOW MUCH DO YOU NEED?
1 Gigabyte (1,000 Megabytes) will be good enough if your budget is tight. 2 GB is better, especially if you are running Windows Vista, watching lots of movies or doing graphic design, and 4GB or more will keep you humming along no matter what you're doing on your PC.

HOW TO SET UP A HOME NETWORK

Home computer networks are extremely useful to have, as you can have just one printer, or one internet connection, and all the computers in your home can use that same device. Here are some guidelines to setting up a Windows based network.

Setting up a home computer network is not too difficult. The simplest network is where you join 2 computers together. To do this, all you need to buy is a network crossover cable, with RJ45 connectors on each side. This you can buy, ready made up, from your computer shop. Make sure the cable is long enough to reach both your computers. Then simply plug it into the socket at the back of both computers.

Once you have done this, you need to give each computer a unique IP address. To do this, click START - SETTINGS - NETWORK CONNECTIONS - LOCAL AREA CONNECTION. (If you have no "Local Area Connection" item, then click on "New Connection Wizard" and make a new Local Area Connection)

Please note that each computer must have a network card installed - if you can't find a socket to plug your RJ45 network cable into, then it means that your computer hasn't got a network card. They are very cheap though, and just plug into any empty slot inside your computer. Virtually any newish computer have them installed as standard equipment.

In the box that pops up, select the Internet Protocol item, and then click on the PROPERTIES button. Click on the little circle next to "Use the following IP address" and then in the boxes next to "IP Address" type in 10.10.10.100 I chose this address because it is not used on the internet, and so it won't conflict with anything when you do connect to the internet at a later stage. You can make the subnet mask 255.255.255.0 and make the gateway address 10.10.10.101. Click the OK button when you're done.

Now you must do the same thing on the other computer, but swop the IP address and the gateway address around, ie IP Address will be 10.10.10.101 and the gateway address will be 10.10.10.100 This helps the computers to find each other quickly.

Now to be able to use a printer connected to another computer, you have to enable sharing on that printer. To do this, click START - SETTINGS - PRINTERS and then RIGHT click on the printer you want to share, and click "Sharing..." in the popup menu. Click the little circle next to "Share this printer" and giive the printer a name, if it hasn't got one. Click OK when done. You can then do the same thing for other things you want to share. Right click on your folders and click on "Sharing and Security.." to share them with other computers.

If you want to have a home network with more than 2 computers, then you need a device called a network hub, and one network patch cable, (also known as straight cable) for each computer. All the cables must be long enough to reach the hub. The procedure is the same as for 2 computers, except you should choose one computer to be the Gateway computer, and give each computer a different 10.10.10.xxx address.

You should then be able to share files, use programs that are on another computer, print on a printer in another room, and use DVD drives in another computer; and this is just some of the uses.

There is, of course, a lot more to networking than this, but this should be enough to get you up and running.