Computer ABCD

ABCD

If someone comes up to you and says, "You have to understand about Viruses, CPUs, GHz, File systems and all the other parts of a computer", then reply, "No I don't, I just want it to work". but if they insist, or things go wrong you might want to take the "nerds" course below. Good luck, but resist it like crazy. If your computer doesn't work call the shop or supplier or buy one that does. Like an Apple Mac or the new iPad.

Being a nerd

These are the things you need to know if you use some computers. Sometimes they simply don't work... This of course puts people off as they don't want to be troubled with things, they just want the thing to work.

Most problems are with Windows PCs, Apple Macs have very few of these issues, if any, and tend to just work. The new Apple iPad is tomorrows computer which will give you most of the applications you need, but it is a closed eco-system, with all hardware and software supplied and guaranteed by Apple, without any problems. It is strongly recommended for new comers to computing.

So what are the issues?

Viruses

Viruses are programs that get loaded on your computer often without your knowledge. They are common on Windows PCs, but unknown on Apple Macs.

An example of a virus might be a program that watches you typing on your keyboard and records each key, then sends these across the internet to a criminal. If you go onto your bank web site, or enter your credit card number on a store, the criminal knows your bank login or your card number. Next thing you know is your bank account is emptied!

Where do viruses come from? There are lots of bugs in the Windows operating system that allow criminals to do things like attach virus programs to emails or web pages. So that when you read your email, or even worse open an attached file, or browse a web page, a virus program is loaded on your computer without your knowledge.

There are a number of commercial "anti-virus" programs available which you can buy to watch for viruses and block them. But they have an ongoing cost to keep their knowledge base of known viruses up to date. You should also always load your computer with any updates that Microsoft releases, don't wait do it immediately. It is also a good idea to change your browser from IE to Firefox or Safari.

Or buy an Apple Mac and forget about the problem.

Drivers

There are many, many different versions of PCs which all run the Windows operating system. There are also many different peripherals, cameras, printers, scanners, etc etc which can be connected. All these variations need special little programs called drivers which Windows needs to know how to talk correctly to the peripheral.

If you have any misbehaviour of your computer or something you buy and plug in doesn't work it is probably that you don't have the needed driver program. To correct this you have to search the internet or ask the supplier to provide you with the program, then install it.

Or buy an Apple Mac, I have never found a peripheral that doesn't just work on the Mac.

De-fragging drives

In a computer there is a component called the Hard Disk Drive (HDD). This is a storage device that saves all your programs and document, music etc. These are stored in files which are recorded on the HDD in blocks, not necessarily contiguous. When the HDD gets full or after a lot of use, the blocks can be scattered all about. This causes the computer to slow down as it has to search around all over the HDD to find the thing you want, program or document or music, etc.

To correct this fragmentation, a special program is used to shuffle the blocks to make them contiguous and thus speed it up again.

This problem is becoming less and less important as later operating systems, Like Window 7 or the Apple Max OS X do this automatically.

DLLs

There is a big difference between operating systems in the way they are organised. Programs on Windows are made up of small parts called Dynamic Loading Libraries (DLLs). These are scattered about on your HDD and when you use the program, only those needed are loaded in your memory.

Sometime these DLLs are not updated, sometimes they are corrupted, sometimes they are simply missing after an update.

This causes chaos and programs do not work. The only cure is to re-install all your software.

The Apple Mac does not use this system of DLL, and so does not suffer from this problem.

RAM & HDD

Computers use a memory called the RAM (Random Access Memory) to keep the programs you are currently using. Over the years the programs have become bigger, and more are running at the same time, so RAM sizes have gone up. When yo buy a computer one of the things the salesman will pitch at you is the RAM size. Typically 1GigaByte (GB) is enough, 2GB is lots. But if you do lots of high resolution photography and editing then you may need double that.

Not having enough RAM will not stop your computer working, but it will slow it down.

The HDD (Hard Disk Drive) is a big storage unit that keeps all you programs and document, music, etc. Whereas a RAM loses all it contents when you switch off, the HDD keeps them safe. Again a salesman will get you to but the biggest HDD he can, at a higher price. Your choice depends on what you want to keep on your computer. If you keep lots of music or videos then you need more storage. For a small system, like an iPod, 16-64GB is enough. For a desktop or laptop, 100-500GB is the right size.

Backup

Just in case your computer fails and when you switch on nothing happens, you should keep a copy of al the things on your HDD. This is done by using a second HDD and copying the information across to it. Obviously you need a drive that is bigger than the one in the computer.

On Apple Macs (here we go again) there is a cute program that automatically backs-up your HDD without you having to do anything, except connect an external HDD (or you can even do it over a WiFi network). And if you accidentally delete a file you need you can go and get it back.

Always buy a back-up HDD with your computer and make sure you know how to use it and which program to use. Ask the salesman.

GHz, CPU

Inside your computer is a part called the CPU (Central Processing Unit) which does all the clever stuff when you are running a program - like adding up, or interpreting the MP3 music to audio or ... The speed at which this thing works is defined by the frequency of a signal that is fed into it. This signal is called the clock and is measured in MegaHertz (MHz) or GigaHertz (GHz). 1 GHz = 1000,000,000 wiggles per second, pretty fast! Again the salesman will emphasis the speed of a computer as indicated by the "GHz". Unfortunately this is not true as mostly the speed is determined by other parts of the system that cannot work as fast as the CPU. Anyway 1Ghz is enouhg for most people, unless you are editing a lot of video, in which case the higher the better.

Some computers have more than one CPU, if the have two then they are called dual core. Dual does not make it go twice as fast, again it depends on other things. But dual is the modern thing so buy it.

USB and other connections

USB (Universal Serial Bus) is a way to connect things like iPods, or cameras, or printers to your computer. When they are connected your programs can talk to them an transfer music, load pictures or print. There are a number of different USB plugs and you need the right cable for each peripheral you want to connect.

You can connect lots of things at the same time, so you may want several USB connection on your computer. I fit only has one, no problem, you can buy a cheap "USB Hub" box to expand the number.

There are other types of connection that you may find, for example Firewire - a very fast connection typically for video cameras or audio input/output. Ethernet, again a very fast connection used for connecting to a network, or your internet router. Some very old computers have a "Parallel port" with a clunky plug use to connect old type printers, forget this or buy a new computer.

KB (KeyBoard)

You type on this. It may have many more keys than just the alphabet. Most of them are just to confuse you. The only ones you may find useful are TAB to jump a column in text entry, SHIFT to get Upper Case letters, Control to do special commands.

One interesting thing about the new tablet computers, like the iPad, or the iPod touch or iPhone is that the keyboard is displayed on a touch screen.You type on it by touching the screen. And the layout can change depending on what the program you are running wants you to enter. For example a calculator will have 0-9 keys, but a word processor will have QWERTY keys. This make the touch screen very flexible.

Monitor

A desktop computer has a connection to a monitor or screen which displays what you are doing. These monitor can be of different size and "clarity". They display characters and videos in a series of very small dots. The number of dots across the screen and down the screen defines the resolution, or the smallest thing you can see, or the clarity of what you display. Screen size is measured across the diagonal of the display area. Sizes vary from 7-10" for a Netbook, 10-17" for laptops, and up to 30" for desktop monitors. Resolution, (the number of dots across) is from 640 to 1920. If you have 640 or so you obviously cannot view well HD TV, you need 1920 for that. 1280 is a good compromise.

Again the salesman will try to sell you the biggest and most expensive. Just take a look at the monitors in the shop and decide which is for you. 20-22" is a good size for desktops, 13-15" for laptops.

File Systems

Ever since the start of time, computers have had what are known as hierarchical file systems. This means a vertical series of "folders or directories" arranged on a HDD, and within them or below them your files and programs. Arranged like an upside-down tree. You may have more than one HDD which will be called, on a Windows machine C:, D: etc. A file on one of these may have the name C:/my Documents/bank/Fax 22-10-08.txt. The last three characters ".txt" tell the system what kind of file this is - a text file. There are many different file types.

It is very easy to create chaos on your computer by not taking great care of the folders you have or that you create and not saving your documents, music etc in the right ones. For example you should keep all the documents about your bank in a folder called My Documents/Bank, obviously.

Things are pretty much the same on an Apple Mac, with "volumes" in place of drives. The volumes have plain names, like "My HDD" or anything you care to name them, which is little easier than "C:". It has similar folders and files. The suffix is not strictly needed on a Mac as it knows secretly what kind is each file, but people use it anyway, to have PC compatibility if nothing else.

The File System on a PC is differently organised to that on a Mac, but you can transfer files easily. If you plug in a USB stick, then take care, a Mac will understand a PC file system, but a PC will NOT understand a Mac file system. So you must format the USB file system as a PC for them both to read the contents of the stick.

NERD CERTIFICATE

If you have got through that lot then you are now officially a "nerd" congratulations. The only thing is you don't need any of it to use a computer, and if you go for one of the new Apple iPads you won't see any of this at all, it just works.