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Mysteries of Your Computer Hard Drive
If you've been following my scant compilation of articles, the next likely subject should be a simplified explanation on how your computer stores
all that information that makes it work. It's also a good time to discuss preventive maintenance on your computer.
The Stuff You Don't Need to Know:
(or if you need a nap have one now)
then skip down to the section entitled "The Stuff You Need to Know".
Your hard drive (file cabinet) consists of a number of disks that have literally billions upon billions of miniscule magnetic particles on them. They are rearranged when an electrically charged read/write head passes over them. It works something like a cassette tape or video tape for your VCR but in this instance disks are the medium rather than tape. When the read/write head passes over the surface of the disk the particles are realigned so that their magnetic poles (north & south), point either one or the other of two possible directions. The next time the read head passes over that spot on the disk it looks at the alignment of each particle and depending on the orientation, it assigns the particle a value of either 0 (zero) or 1 (one). Now you've got the information that was on the disk converted into what mathematicians refer to as "binary numbers". (Snore) Once a mathematician got hold of this concept it wasn't long before they were doin' all kinds of fancy new calculations. Somehow along the way someone figured out that due to limitations of electronic know how, the available technology favoured and functioned best using a hexadecimal numbering system. (We won't be discussing the particulars on why. I'm basically skimming the surface here with as little technobabble as possible. To explain this thoroughly would encompass such topics as the history of computers and would take hundreds of pages).
A good mathematician (not me), can easily convert binary to hex. The next step was to make those numbers do something for the average man. How do you do that? The easiest way to communicate is with words and symbols. So some genius took the hexadecimal numbers and invented a way to convert that math into letters and numbers. That was the beginning of computing on a fairly large scale. Word processors and operating systems were born.
Working with numbers was one heck of a tedious way to create programs. So it is not surprising that different tools have been invented along the way that convert hexadecimal numbers to regular old text automatically for the programmer. Nowadays most of the computer code used to create the software we all use resembles a sort of cryptic english and is therefore much easier to use than all those nasty hexadecimal and binary math calculations of old. In fact, a software programmer could and likely does create software with little or no knowledge of binary or hexadecimal math at all.
Of course the most widely known and used operating systems in the world are Microsoft's Windows 3.1, 95, 98, Millennium and Microsoft's NT/2000 systems. The computers we are all using today still have all those elaborate calculations going on, we just don't see it. Thanks to Bill Gates, it's all hidden by the pretty pictures also known as Windows.
 RRRRRRRRRRRING !!!!!!!!!!!!
Ok, anyone napping it is time to wake up for.....
The Stuff You Need to Know:
Now for the more simplistic explanation of the above.
Hopefully by this point everyone knows the computer was created to store information from accounting data, to pictures of the grandchildren and thousands of other tidbits.
Where's all that stuff stored? Why it's in the hard drive of course. If we use the analogy that your hard drive is like a big filing cabinet, what would be the most important thing about filing a document? How about having a system to locate the document at a later date. With file cabinets, the accepted system is to sort files by alphabetical order. That works just fine when you are storing hundreds or perhaps thousands of documents, but what if you have millions or perhaps billions of documents. Hard drives today store an enormous amount of data and with the alphabet limited to a miserly 26 characters, it wouldn't take long to run out of letters. Numbers on the other hand are infinite so it makes sense to keep track of the location of your files using a numerical system. Like the hanging folders in a file cabinet, the hard drive is divided into millions of small units and each one has a number assigned to it. Picture a huge apartment building. It has individual floors with several apartments on each floor. Each apartment has a unit number. Imagine each apartment as one storage unit on the hard drive. Your accounting information is in apartment 206 and the grandchildren's pictures are in 1023. If you are standing in the lobby looking at the index on the wall you could easily see that your accounting stuff is on the second floor in unit six hence (206), likewise the grandchildren's pictures are on the tenth floor in unit twenty three (1023). The computer uses a similar system assigning a location (or address) to every piece of data stored within the hard drive. Once the data is stored, the computer lists the address in it's own index to ensure easy retrieval.
Getting to the point of it all:
(or maintaining your computer)
Not unlike humans who sometimes misfile documents in a file cabinet under the wrong letter of the alphabet, your computer will misplace data. (Don't ask me how because that's another long story just trust me that it happens). Humans deal with this dilemma by digging through all the other folders in the file cabinet until the darn thing is found. The computer goes to it's file cabinet (hard drive) and when it doesn't find what it was looking for it just goes "what the h$*#!!!!!". Since it hasn't the intelligence to deal with lost data, the system is very likely to crash. Crash is technobabble for cease to function.
ScanDisk and Disk Defragmenter
Lo and behold, the computer geeks who invented this system know about the problem of lost data so they built a couple of programs to help minimize the possibility. As a computer owner it's important to know how these programs work and to use them diligently.
ScanDisk does the same thing that we do when we go through a file cabinet looking for files stored in the wrong folders and then refiling them where they belong. Sometimes it will find part files and have no way of knowing where they belong. It's a good idea to run ScanDisk (sort your files) at least once a month. Neglecting to do so will just cause your files to get increasingly jumbled over time and you know what happens when your computer can't find what it's looking for .... it crashes. You can start ScanDisk by clicking Start, pointing to Programs, pointing to Accessories, pointing to System Tools, and then clicking ScanDisk. This is what you will see.
Figure 1
Most computers have only one hard drive. You need to click on the (C:) drive, make sure that "Standard Type of Scan" is selected. You can also select "Automatically Fix Errors" and then just click on the Start button. This will keep your files sorted properly and in tip top shape if done regularly.
Disk Defragmenter
You can use Disk Defragmenter to rearrange files and unused space on your hard disk so that programs run faster.
You can start Disk Defragmenter by clicking Start, pointing to Programs, pointing to Accessories, pointing to System Tools, and then clicking Disk Defragmenter. Check out Figures 2, 3 & 4. The picture in Figure 2 shows an interface where you may select the hard drive you would like to defragment. Since most computers have only one drive we will use the (C:) drive. If your computer has more than one hard drive you can select it from a list by clicking on the drop down arrow. That's the arrow directly to the right of the box that says "Drive C Physical Drive".
Figure 2
Once you have selected the drive and click OK you will see what's shown in Figure 3. Clicking the OK button has automatically started the defragmenting process. Sometimes you may get a message that says this drive is only 1% fragmented or some other low percentage and does not need to be defragmented at this time. Don't believe it. Go ahead and click the OK button to defragment anyway.
Figure 3
If you click on the "Show Details Button" you will see a representation of your hard drive (Figure 4). Here's where I get the apartment building analogy. Look at all those tiny little apartments. Each one of those little boxes holds a bit of information. Sometimes the amount of information you are storing takes more space than one of those units can hold. In this case, your computer looks for the next available empty space and puts it there. Related data may end up all over the place by the time adaquate space is found. Spreading the data all around like this slows down the entire process because your computer has to search all over for the files needed to run a program. It would be much more efficent to store associated files all in one place. Disk defragmenting does just that, it checks all the files on the hard drive and then groups them together accordingly.
Figure 4
I hope this has been more enlightening than boring because following a regular routine of using these utilities can save a lot of hassles and make your computer run more quickly and efficiently.
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