ARCS shield icon75Avon River Computer Service

More Than Just Computer Repairs


Tune Up & Servicing

Everything benifits from a good service now and again, and yet, its probably the single most neglected task that computer owners do. Every day, you visit hundreds of sites and each time you enter a site, there are images and files downloaded to your computer. Normally, Windows takes care of these and over time, these temporary files are deleted. I say normally, because there are times when Windows tends to forget where hese files are and therefore do not get deleted. These files are doomed to reside on your hard drive until the bitter end, unless you get in and clean them up.

How do these files get missed?

There are a number of reasons that these temporary files get missed from the house keeping schedules. Probably the most important one is when the computer crashes or doesn't shut down properly. Normally, when the computer is shut down there are a lot of things happening in the background that sets the computer up to shut down, one of which is to purge temporary and unnecessary files from the hard drive. If the computer crashes, or doesn't shut down properly, these files do not get deleted and when the computer starts up again, the system will not know that the files have not been deleted and will go on its merry way writing new temp files along side of the old ones. Eventually, this can lead to computer slow down and other issues.

The Internet & System Caches

Back in olden times, when dial up was the norm and broadband was just a fantasy, navigating the Internet and displaying the pages was slow. The reason for this, was that the fastest speed they could squeeze out of dial up was a theoretical 56kb/s under optimal conditions. Most people were connecting to phone lines that had been in place for many years and as a result, their maximum speed was much less than this. Developers came up with a way of getting around this limitation by introducing the Internet cache. The logic behind this was that if the user visits a website once, chances are, that they will probably visit that site again. If they saved all of the websites data, images etc. in cache, (read hard drive), the next time the user went to that site, it could be displayed, not from the Internet, but from their own hard drive. This would give the appearance that the web site loaded super fast and only changes to the site since the last visit would have to be downloaded. While this was a great leap forward, now that most people have broadband, caching is not the issue that it was, but the cache is still in place, doing what it was meant to do for dial up users. Now, we tend to visit hundreds of sites everyday and the information from each and every site is still being saved to your hard drive, but now it is actually slowing down your browsing because instead of downloading and displaying the site you are visiting, it checks the cache first to see if you have visited it before and if so, display the cached version rather than the current version from the Internet. As the cache gets bigger and bigger, it takes longer and longer to go through. I have seen a computer crippled to the point that it takes minutes between clicks rather than the seconds that it should take. You should clean up you Internet & system caches on a periodic basis and at a minimum of once per year.

Defragmenting your hard drive is a good way to keep your computer humming.

The way that Windows writes files and data to the hard drive is that the files are broken up into blocks of data and these data blocks are written to the drive wherever they will fit. There is a master boot record which keeps track of the start of each and every file on the hard drive and each data block contains a reference to where the next data block or fragment of file starts.

You could think about your hard drive as a large book, and each data block is like individual words within that book. Each space for a data block is a set length, say 8 characters long, so some words may span 2 or more data blocks and some may only occupy a couple of characters. A file might be thought of as a paragraph. Now imagine the publisher thought it would be a good idea to break all the paragraphs into individual words, pull these words out of a hat randomly and place them onto the book where they would fit. At the beginning of the book, they have put an index to the starting word of every paragraph in the book. At the end of each word, there is a reference point to where the next word is on the drive. To read our sentences or paragraphs in our book, we have to know the code of how to put all the words back together to make sense of the story. We would go to the index to find out where the paragraph begins. we then turn our pages until we find the start of our paragraph. at the end of the first word, there is a reference to where the next word is until the entire paragraph is read.

To use our analogy above, on your hard drive, the index is in the master boot record. This has changed with the latest versions of operating systems, but the MBR serves to illustrate my point. The master boot record has, in its records, the starting point of every file on the hard drive. When we choose to display our file, the MBR knows where the start of that file is on the hard drive. It then moves the head, the disk spins and the first part of the file is read. The end of the block tells the computer where the next part of the file is located and the head is moved ready to read that part when it comes around. This process continues until the entire file is read and it is displayed on your screen, output to a printer etc.

Now this process is pretty convoluted and involves a lot of moving, aligning and waiting for the disks to spin around to read the data. Wouldn't it be easier if the files data blocks were all in a line? Yes it would, and this is where disk defrag comes into play.

Defragmenting works by taking the second data block of a file and moving it so that it can sit alongside of the first. In order to do this, it may have to move other data blocks from different files and relocate them to somewhere else on the drive before it can move the data blocks of the first file It will continue to do this until the entire file is in a continuous line and it can move onto the next file in the list. Once the defrag process has completed, the MBR can tell the read head where the start of the file is, then the head basically stays where it is because the next data block will be the next one it is looking for. There is no waiting time while it moves the head and waits for the next block to come back around.

Avon River Computer Service can clean up, tune up and service your computer to ensure that it is running at its peak.