Mobile Computing

Buying a computer.

You don't need to spend a fortune to buy a laptop. You also don't need all of the whiz bang features that some high end lap tops have. I expect that most people would probably only need a laptop capable or funning Windows XP or maybe the older Windows 2000. About the minimum specifications I would recommend are:

That sort of computer will run Widows XP, but slowly. A better specification to run Windows XP would be:

I paid just under $800 for a laptop with the above specification in 2003, so you could definitely expect to buy one for that price these days. A laptop with the above specification will handle your needs for years. I'll explain what all the numbers and terms mean.

Mega hertz and Giga hertz. These terms are used to measure the processing speed of central processor units, or CPUs. The CPU is like the brains of the computer. It does most of the calculations, or 'thinking' for the computer. In the 90s, computer processors used to be measured in Mega hertz. A single Mega Hertz was a million calculations per second. Technically it is not quite a million, and the calculations are called 'floating point operations' (flops). But to keep it simple, think of a million calculations per second. Which sounds a lot, but it is not. Really early computers used CPUs that were capable of about 20 to 23 MHz My first IBM compatible computer was capable of 66 MHz Once CPUs became powerful enough to reach 1000 MHz, a new term was introduced, the Giga hertz, or Ghz. My laptop can do 1.4 Ghz, or 1,400,000,000 flops per second. That's plenty enough to run Windows XP, a word processor, a web site tool and several other programs at once. The faster CPU speed you have, the faster your programs will run, to a point. Having said that I don't notice much difference in speed between my 2.4 Ghz CPU computer at work and my 1.4 GHZ laptop at home. Both still take ages to start because of the slow speed it takes to get data from the hard drive.

Gigabyte and Megabytes are used to measure the storage capacity of hard drives and RAM. The hard drive and ram store programs and data. A hard drive stores programs and data when the computer is both in use and not in use. Think of it a lot like your long term memory. When you go to sleep and wake up the next day you still remember things. Your hard drive works a lot like that. Your RAM on the other hand will only work when the computer is switched on. When a program is running the computer gets the information from it from the hard drive and puts it in to the RAM. This is because accessing data from a hard drive is relatively slow, and getting it from RAM is very fast. Having more ram also allows your computer to store more data in a sort of working area, which means it does not need to get it off of the hard drive so often, which means it works faster. So more RAM can definitely have a noticeable difference in the speed in which the computer operates. If you need to spend more on the computer, go for more RAM. 256 MB of RAM is a good starter, but 512 MB is better, and 1 GB is better still. Above 1 GB is probably not worth it unless you are buying this newfangled Windows Vista version out from March 2007.

When it comes to hard drives you may not need a huge among of hard drive space. I used to get by on half a Gigabyte. That was back when I ran Windows 3.1, back in the 80s. Now I have a 40 GB hard drive, which I have half filled in three years. I don't use much video though. If you have a fast Internet connection, then you might need a bigger hard drive. If you live in a car or van though, I can't imagine you will need a big hard drive because odds are on that you won't be accessing the web very fast. I would say anything from 10 to 20 GB will be fine. 40 MB would probably be more than enough.

CD ROM. These days you will need a CD ROM. on your computer. This is because almost all software (programs, Windows, Games, etc) come on CD. If you can get a DVD ROM. or DVD burner, even better. It is nice to be able to watch DVDs on your computer.

Mouse pad or mouse pointer. Every laptop these days seems to have one of these. Instead of a separate mouse moving about on a desk, you use a mouse pad to control where the pointer goes. If you can't see one of these, ask the salesperson how the pointer is controlled. These can take a while to get the hang of.

How do I know what is good value for money?

Shop around, research. The best way to find out what is good value for money is to work out what is selling for what. Go by a copy of a magazine like the 'computer trader'. Look at the adds and get an idea of what sells for what price. Keep in mind that desktop computers will always be cheaper than laptops for a similar specification. Go to computer fairs. Look at the prices of what is selling for what. Take a look at laptops and ask if they are second hand. Check in computer shops. Ask questions. Look at web sites that sell computers. Get an idea of what your money can get you.

How do I know I'm getting what I pay for?

If you have a computer running Windows XP, you can easily check the specifications of the computer before you buy it. Start it up if it is not already on, look for an icon on the screen that reads 'My Computer' or similar:

Double click on the icon. A Windows explorer type screen will come up, with an option towards the top left that reads 'View System Information' like so:

Click on that option and you should be taken to a small window on screen that looks like the image below. Under the general tab, it lists the Processor, and the amount of RAM. These figures should be either exactly as specified, or very close to it. Note that on my computer it reads that it has 240 MB of RAM, when I know it actually has 256 MB of RAM. Some people measure a MB as 1024 kilobytes of RAM times 1024 kilobytes, or 1,048,576 kilobytes. Others (usually salespeople) measure it as 1,000,000 kilobytes. For RAM this is not a big issue. For hard drives it is.

At any rate, the CPU speed should be as specified. There is no excuse for getting that wrong. If it is not, you should ask for a discount, or not buy the computer. The discount should be based on how much slower than specification the CPU is. If you are told, or read on the computer's advertised details, that the CPU was say 2.4 Ghz, and it was only 1.8 Ghz that is 25% slower than quoted! So ask for a 25% discount as minimum, especially if the RAM and hard drive are not up to specification as well.

How to check hard drive size.

Close the System Properties window and go back to the Explorer. Move the mouse pointer over the hard drive icons and hold it still. A little box should pop up displaying the total size of the drive and how much free space it has. Like so:

Now this is where that different measuring of drive space comes in to play a lot. That drive there on my computer is supposed to be 20 GB. That should be 21,472,836,480 kilobytes (1024 x 1024 1024 x 20). But if people measure a megabyte as a million kilobytes they can say that it should be ( 1000 x 1000 x 1000 x 20) or, 20,000,000,000 kilobytes. Either way my so called 20 GB hard drive ends up being less than specified. Some additional space is lost by formatting the hard drive. So that's more space lost. As can be seen, about 12% of space was lost here. Not good really. This is typical though. The 'formatted' space of a hard drive is always lower than the manufactured space.

So ask what the 'usable' or 'formatted' hard drive capacity is. If they bullshit you on that, and it is way out, ask for a discount again.

Where to buy a used computer.

There are stores that specialise in selling refurbished computers. These are probably the best place to buy from. They should offer a minimum three month guarantee. They are also in one place, so unlike a computer brought on eBay or at a computer market, you can return to the store to fix problems. You can buy such computers from markets and eBay, but you can generally not be sure that you are getting what you pay for, or that it will work.

You can also buy discounted computers at some stores where you can ask if they have any discounted demo model computers for sale.

Where not to buy computers from.

Anywhere that has high pressure sales people. The second specification computer I have listed above will be fine for pretty much everything apart from high end games and Windows Vista. You don't need Windows Vista as of 2007. Windows XP will be fine, so for that matter will be Windows 2000 or Windows 2003. If you just want a basic computer for surfing the web and reading email you won't need anything better than what I have specified unless you download a lot of TV shows or video. In that case a bigger hard drive will help. If the sales people try to convince you that you need the latest and greatest, it will really mean they need the commission for selling you the latest and greatest. You should not have to pay more than $1000 for a low end lap top these days. If they try to charge you that much, shop around. You can buy a refurbished laptop for between $200 for a really basic one, to about $700 for the second specification above. Office Works in Australia have long sold brand new Acer Laptops for the $890 - $980 price range.

I suggest you avoid the more expensive chain stores where sales staff get paid on commission.

© 2007 Romana S. This text is copyright. The ideas and concepts are not. Feel free to link to it, but if you want to put it on another web site ask for permission to do so in the forum. Not for release on commercial web sites or Wikipedia or Wikibooks.
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