Ever wondered what goes on inside your computer, or why it doesn't always do what you expect?   Like a magic genie, just give your command and off it goes to do the work to edit that document, run your calculation, change that picture, or play a movie. Inside the computer are millions of parts and thousands of programs all working together to fulfil your wish.  Unfortunately a failure in even one small part or in a program will cause errors or crash the computer.

The complexity in a modern PC is almost impossible for the brain to comprehend. Try getting your head around the scale of the current desktop computer system as represented by the following statistics.

• When the first microprocessor chip was introduced by Intel in 1975 it had 2,300 transistors, the current versions have more than 500 million.
• The Hard Drive in your computer, which stores all your programs and files, is an electro- mechanical device that spins at around 7200 revolutions per minute. The read/write head floats above the spinning disk at a height of only 3 nanometres.  By way of comparison, if the disk were the size of the earth then the head would float only 25 cm above the earth. Not much space for error!
• A typical Windows 7 computer has more than 80,000 program files and over 200,000 individual program settings which are stored in the computer "registry".  Errors in any of these files or settings can cause the computer to malfunction.
• Windows 7 can work with thousands of different pieces of hardware and comes with in built support for more than 5000 different types of hardware from files stored in its library.   These hardware files are called drivers.

Thankfully, computer systems are relatively reliable despite their complexity.    Lets then look briefly at some of key components inside the computer and where problems can occur.

The  Central Processing Unit.
Also called the CPU or brains of the whole system.   These are now incredibly tiny and powerful.  Smaller components means the computer can be faster, more capable and use less power. Fortunately the central processing unit is one of the most reliable parts of the computer and can be expected to last years, even with 24 hour operation. Usually other parts of the computer will fail before the central processor does.

The Hard Disk.
The hard disk is the permanent memory store insider the computer.  Being electro- mechanical it is more prone to error than the non moving or so called "Solid State" parts such as the CPU.  Unfortunately hard disk failure will result in loss of your data, so it is a major catastrophe when it does fail. That is why it is so important to constantly save your data to a back up device.   Minor hard disk failures can also cause glitches in the programs which can look like software faults.

Operating System
The operating system is like the autonomous nerve control system of the brain keeping a watch on everything and keeping things organised.  With the Windows operating system,  Microsoft has invested billions of dollars in time and effort  to ensure the software is reliable. Microsoft has an army of testers, to try out every function and combination of functions to find mistakes and correct these before the product is launched.   Even after launch continual updates are used to correct errors when they are found.

Microsoft has also built in a range of self checking and correcting features into Windows 7 that automatically fix common errors when they occur.  The system configuration is automatically backed up on a regular basis and when any changes or updates are made to the computer. In the event of a failure of the system settings the previous state of the computer can be restored.

Other Hardware.
The great strength of the Microsoft Windows system is its ability to support a wide range of hardware and software from thousands of suppliers.   This gives the Microsoft windows system its incredible flexibility to suit a wide range of needs, and also fosters competition amongst hardware suppliers which keeps prices down.    It is a considerable challenge for both hardware suppliers and Microsoft to keep the system functioning smoothly when supporting a huge range of different types of components.

Overall
Considering the millions of parts, program files, settings and hardware types that make up a modern computer it's no wonder they sometimes fail.  In next month's  article we will talk about what the average user can do to help overcome computer problems and seek appropriate help when problems do occur.