From the age of around five I have been using a computer, of course there were a few mild mishaps at an age so young, such as when I stood on the CD drive and snapped it off or when the screen came crashing to the ground. But I have learnt from these experiences and from that I have gained more knowledge so that now at the age of 14 I know not to stand on the CD drive and not to use the screen as a step ladder. But learning from small things like that has allowed me to become confident enough to build my own computer and almost secure me a position in the IT industry.

But for a majority of people a Pentium Processor is completely irrelevant to their understanding of computers as is a Hard Drive and Graphics Card etc. And sometimes I wish I was one of those people who didn’t have to know about technology and just lived life easily and relaxed but life isn’t like that, we are all here for a reason and we all have a purpose, but that’s a whole other story that I will rant on about some other time. Back to technology;

One great thing about computers and the Internet is money. It is a huge industry and one of the main way users earn money off of the internet is through advertising. I built a blog/website about a specific computer that I own, www.imacupdate.blogspot.com and on the site you will notice there are adverts. Every time someone clicks on one of them I get paid. Simple as that, and that is one of the reasons people are quitting their jobs to become these so called ‘Internet Entrepreneurs’ expecting to make millions from doing nothing. It just doesn’t work; it takes weeks if not months to even get it started and you may still only earn small change. I won’t say how much I earn but if you are interested please email me at the address at the bottom of the page.

Now onto the problems with computers, it’s always when you most need to use it. You need to e-mail some really important work to someone or need to retrieve a file from your computer. Then you hear the dreaded beeps just seconds after you turn on the computer and an error message saying ‘Warning, major system error…’ Oh fiddle, what can you do, the list is endless, restart, Ctrl + Alt + Del, off and on at the wall, check all the connections (by the way, in my experience, it has never been because of a loose connection otherwise it wouldn’t turn on, duhh), the list never ends. Finally you give up and take it to your local computer repair shop. They will then keep it for a number of months because the employees are too busy fantasizing over the new 8GB RAM module that has just been released.

Once you finally get it back in 2013 you are only too pleased to find that it has been repaired and everything is working again. Only when you get home to find that your Hard Drive has been wiped clean, all of your Photos, Music and Videos are gone. You then spend an hour cursing down the telephone at the manager and the best answer the can come up with is something you don’t understand. You then accept defeat and retire to bed.

Computers can cause more stress in a few hours than anything else can in a lifetime. Therefore, only buy one if you need one. I hope you have enjoyed reading this as much as I have writing it.

A simple search on Google can prove it with images. Some scientists are already inventing ways to use that heat to produce electricity. The waste would be greatly reduced and you could enjoy a cooler computer. Now if you want to know the next thing you need to build the computer is the motherboard. This is the control center of the computer. Every component is linked here someway.

The CPU connects here, the hard disk too, the power supply too, the graphic cards too, everything. Start by installing the CPU int he motherboard and then the cooler on the CPU. Never turn on the computer without the cooler or you risk having to buy a new one. The next thing is connecting all the cables you can see to the motherboard. The power cable, the electric cables, the power supply energy cables. When that step is complete connect the DVD ROM or Blu Ray and the Hard Disk too. Get a one Terabyte hard disk. They are very cheap these days. Then connect the two cables to the hard disk.

One for power the other for information. Never turn on the computer with these cables bad linked, you can burn both the motherboard and the disk. I already done it once when I was playing with an old computer when I was 12... It made a very loud noise and the lights went down! Just be careful, this is serious, not a game. Finally connect the graphic card if the motherboard does not have one integrated, turn on the computer and you are done.

I am sure you are thinking me build a computer, yea right. But really it isnt much harder than building an engine or, for the ladies, cleaning a house. You know where everything goes and how it is soposed to be. All you need to get started is an open mind, this book, a little bit of money, and some patients, for those who have a short fuse.

We are building a simple internet box. As I mention some of the parts that I am buying for myself dont get to upset if you dont know what it is. If you want to get the same parts as me that is fine I am getting all of my stuff from Frys. You can go to there store and ask them if they have a part that you had read and they should be able to assist you an any way they can. You really need to deside if you want a fancy looking computer or a plain jain one. Me I went with the fancy dancy one, so my computer had costed me a little over a thousand dollars. Ok once you are ready to get started on creating your machine turn the page. Good luck, and I hope this book answers everything for you. If you have any questions or comments please email Aubrey directly at A.CElectronics@yahoo.com or you can try aubreyltechman@yahoo.com. The "l" in aubreyltechman is a lower case "L". He checks both emails daily.

Chapter 2: Lets Get Started

There are a lot of ways to get your computer parts. You can order online, store, or yard sales. If you are wanting to order off line I will give you some email adress in a minute. If you want to go and get the parts from a store I would recomend goign to best buy, frys, circut city, staples any of those stores will be able to help you get everything you are looking for. If you are going to a yard sale to pick up a computer that might be a cheaper rought, but at the same time it might not be. Maybe the computer is there because it has a virus or it is way out of date. If you get a computer that is out of date then some of the programs you want will not always work properly, or if it has a virus then you could spend hundreds trying to get it fixed. But if you are getting a computer from the yard sale to check it out so you know how to hook everything up or using it as a learning computer that is a great start. Atleast that tells me that you are really intreasted in learning, but not everyone needs to do that. Some people can learn this whole book in just one read and can remember everything that I am talking about. If you are still wanting to oder off line then I would suggest going to frys.com, bestbuy.com, or you can try my website as mentiond before A.CElectronics@yahoo.com. You can look around the internet for more computer stores and parts, you might even want to try ebay. Like I had said before the computer that I am building costed me a little over a thousand bucks. But it is a small gaming system and a great internet box, I have two o.s. installed on it, we are going to touch that subject a little later. Before I mention anything else get your wallet full, we are going shopping, I am going to give you a price of what I got and where I got my parts fom. I had bought all my parts at frys. I went there myself, it was a mistake, my wife is kinda mad at me for dropping over a thousand bucks in one store while I gave her tweenty five to go to some jewlery store. OOPs I love you babe.

Chapter 3: Shopping for the GUTS (inside of the computer)

The first thing that you need is a "shell". This is what will hold all of your guts, parts, what ever you want to call them. You dont even need a fancy shell, with all the lights and gadgets. You can use a piece of two by twelve. Yes thats right you can use wood to build the shell. The only thing that you need to know is how long you want it. You need to fit the motherboard and cd/dvd player on it as well as everything else. As for me I would like to get a semi fancy shell. So I got me an Antec Twelve hundred tower for two hundred and eight dollars, excluding tax.

Now we need the main part of the whole operation, the mother board. This part is what tells what to go where. With out this, its like having an car body without an engine, or its like having a house without floors and walls. I had picked up an Intell media series boxdg 45ID socket 775 from frys for about one hundred and fifty bucks, but I got it on sale. Most mother boards come with there own cpu. Central Processing Unit. If yours doesnt come with it then you would need to ask a sales clerk to help you find a cpu for your motherboard. The cpu is like the heart of the computer, with out it nothing goes anywhere. But differnt types of motherboards need different types of cpu's. You dont have to get exactly what I get, everything basically hooks up the same way. So if you are looking for a cheap computer the parts are out there you just have to look, or email me and I can look for you.

Ok so now that we have a cpu and motherboard and the shell now we need the most inportant part, the harddrive. This holds all of your data. Consider it like the cab of a truck or the living room of your house. But dont you hear the computer technicians talking about something about a memory strip? yes those memory strips hold all of the data that you use every day. So how do you know how big of a harddrive to get. Depends on what you want and what you are going to use it for. Me I had picked me up a terrabit harddrive. That is the best harddrive ever. I got one at frys for only ninty nine dollars. For those who are lost its like getting a chevy long block for only ninty nine dollars.

So now that you have the basics of what you need to get your computer up and runnig, you need to know if you want a cd/dvd player or burner in your computer. Me I got two dvd Emprex dvd burners to stick in my machine. But if you are wanting to do use one just for playing cds then you really just need a simple cd player that you can pick up from a computer store for about fifteen to tweenty bucks.

Now before you get to along we need to get some memory, like I was telling you earlier about the data that you use every day. Well its time to go get some. I snagged me up a four giga bit ddr2 pc 8500 doul memory for fifty four dollars and ninty nine cents. Now that you have all of that you have a choice, do you want to use the video card, sound card, and modem that comes with the motherboard or are you going to get something a bit better like I had done? Me for my sound card I picked up a Creative labs Sound Blaster for sixty bucks. And as for my video card I got me a PNY GeForce 256 mega bit ddr for a meer sixty bucks as well. So now that my video and sound is in hanced I dont really need a modem, they all work just the same way, plug in the phone line, turn on the internet service and go. So I have decided to stay with the modem prebuilt into the motherboard. Now you have everything that you need to build a computer lets go back home and start the building, shall we. Once you have it all together then we need to go back shopping later for stuff like monitor and speakers and stuff like that.

Chapter 4: Building the Computer

Great now that we have everything to put your machine together lets start by taking out the shell from the box, or if it doesnt have a box then you can take off the plastic wraping from the shell. Take off the side of the case to check to see if you have a fan prebuilt into the back of the machine, and a power supplie at the top of it. The power supplie has a bunch of cords hanging out of one end. If you dont have either then you would want to go get one as soon as you can. The fan can wait until you go get the other stuff but to see if your progress works you might want to get that when ever it is possible for you to. Now you need to take the motherboard out of the box and install the cpu. This is a really simple task to do, all you need to do is once you have the mother board out of the case and wrapper then take the cpu out of its box look at the motherboard and see if you can find either a white or gray square box with a lot of wholes in it. Now take the cpu and put it in the with the stems pointing down. Note that the silver bar next to the squar needs to be up before putting the cpu in. Then once it is in put the bar back down to lock it in place. Now that that is done with, we can move on to putting the motherboard in the shell itself. Take the motherboard and put it into the shell were the ports that you can hook up the stuff at is facing out of the back. If you are confused about how to install it, take a look at the owners manuall. There should be a picture of how to install it and what goes where. Now that you have all that done, we need to ancor it down with screws, this is a really easy task to do. Once you have that done we can move on to the next step. Giving the motherboard power. Take the biggest cord from the power supplie and plug into the motherboard. There is a specific spot for everything, just look around until you have found it. Now take the smallest cord from the power supplie and do the same thing, basically what you are doing is looking for spots for the cords to go, if you cant find any other slots for the other cords that is because they dont go onto the motherboard they go to cd/dvd players, and harddrive. Speaking of wich we need to get started on installing the harddrive.

To install the harddrive you need to take it out of the box and place it at the bottom of the front rack located at the front top of the shell. Now that you have that in place you need to secure it down with the screws it came with. Now take the data strips and plug it into the back of the harddrive and plug the other end on the motherboard, like I said before just look for a spot on the motherboard that you think it would fit, it is usually located at the bottom of the motherboard. Great now if you have any cd/dvd players or burners install them the same way. See how simple this is comming along? Now once you have all those in place you need to give them some power, take one of the cords left from the power supplie and plug into the back of your harddrive and any players or burners that you have.

Now you have built a computer! Yea congraulations. Now here comes the fun part, shopping again. If you would like to pick up anything else for your computer then be my guest, if you would like help installing it please email me at my emails mentiond abouve.

But first you might want to plug in your computer to the wall using the power cord that should have came with the computer to see if it works. If it did not come with one then you would need to buy one while we are out.

Chapter 5: Shopping again, monitor, keyboard, etc.

Great now you are back at the store again to drop some more money. But money spending is good right? I think so. Any way lets get a monitor so we can see what are computer is doing, I had found me a Gateway HD1700 seventeen inch lcd flat panel monitor for one hundred and sixty nine dollars. If that is a little way out of your reach then you might be able to get one for about fifty bucks at some computer store or yard sale. Try looking on the side of the road, I had found a working monitor. To tell the computer what you want it to do you need a keyboard and mouse, I found one for sixty bucks. But mine is a Logitech cordless mouse/keyboard combo. If you want to hear sound comming from the computer you would want to invest in some speakers. Now how you would want to hear the sound determens on how much you are going to spend. Ispent two hundred dollars on a Logitech 5.1 souround sound speaker set. But like I said there are cheaper parts out there somewhere you just have to look around.

Now that you have everything you are still mising one important thing, the o.s. (Operating System, Windows, Unix, Linux.) I am installing both o.s. I am installing Linux and Windows xp home eddition. For those who are not all that computer knowledged it is a little bit of a complicated task to do. Once you have decided on what you want then lets go back home and put it together and see what you have done. Now you are probably asking how much is it for windows and linux and what is the differnce. Well I would recomend getting a linux o.s. because it is almost impossible for linux to get a virus, unlike windows you are on the internet for about an hour and next thing you know VIRUS ALERT! god that is anoying. Dont you hate them stupid popup ads. So the choice is yours, either one is a good choice. If you cant decide then go with both, you are already learning whats a few more steps right? If that is the choice you are going with and you need help installing two o.s.'s then email me at one of those two links mentioned eairler.

Chapter 6: Installing the Extras!

Now that you have all the extra goodies lets hook em up. Do just like I had mentiond and take the cords and find out were they go. If you have any fancy dancy stuff you might want to look at the owners manual to learn how to hook it up properlly. I could help you out if you want but I dont know what you have with out you telling me. Now once you have all of it hooked up we need to install the o.s. Now put the install cd into your cd/dvd player and restart your computer. Now just follow the simple step by step instructions on your computer as they pop up. It is really simple. Now you can tell everyone that you had built a computer! Go out and have fun, or just stay in and never get off of your computer. Your choice. Check out some of my other short books to learn more about differnt stuff. I would like any feedback on any topic that you would like to learn. So if you have anything that you would like to learn email me and I will write a book about it and send you a copy either email or by mail.

Though both the PCs and the Macs retain the feature of running an operating system, the operating systems that can be installed on each computer vary. An operating system is a collection of software that runs the computer while it is on. Nearly any operating system can be installed on a PC, including Windows and Linux. The only operating system that cannot be legally installed on a PC is the Mac OS. The Mac OS comes in several versions, and a new version is released nearly every year. Most PCs include an operating system pre-installed. Macs come pre-installed with Mac OS X, a series of Mac OS operating systems that have been used since September 13, 2000. The current Mac OS X version is Mac OS X 10.5.4 Leopard, and a future version of Mac OS X is planned for release sometime during the summer of 2009. Through the assistance of Boot Camp, a program that has been included with Mac OS X 10.5 Leopard and will be included in future versions, users are allowed to install different operating systems onto their Mac through the creation of partitions on their hard drive. Just as an operating system is a form of software, security programs are also a vital form of software for a computer.

Security is another issue between the PCs and the Macs. Both PCs and Macs have the ability to log onto the internet, and when they have fully accessed the internet, they can be easily bombarded by viruses, spyware, and adware; which are all harmful to a computer, whether it is a PC or a Mac. PCs never come with security software, and the Windows operating systems do not include security. Macs, however, have built in, high-level security that is built into Mac OS X because the operating system is coded in Unix, a form of coding language. Along with software differences, PCs and Macs have differences in hardware.

Hardware-wise, Macs and PCs are very different. The most noticeable design feature on the Mac is a glowing Apple logo. Macs usually have a glowing Apple logo on the lid of notebooks or the side of desktops. The design of a PC varies by the company that developed it. Ever since Apple has started using the PowerPC G4 Processor platform, they have started to use more environmentally-friendly materials in their Macs, such as aluminum and glass. Most Macs these days are made of aluminum, and have a glass monitor. For one to upgrade the hardware of a PC or a Mac is not uncommon. Hardware upgrades allow computers to run faster and more efficiently. Most upgrades on a laptop are for RAM, yet on the Apple MacBook, upgrading the hard drive, normally a difficult feat on a PC, is easy. Apple's professional desktop, the Mac Pro, contains no visible internal wires, and there are very few situations where a screw driver is required for an upgrade. Though the PC and Mac are very similar and different in scores of ways, they have made a great impact on the world today.

Computers have been the scaffolds for world-changing innovations since their creation, and they impact the world greatly. I could never imagine the world without computers, and the introduction of PCs and Macs has only opened a door of opportunity for the world, and although they are very different, they have created the path for more advanced technology, and will send mankind further into the future.

Computer magazines, available in stores, offer great variety and many focus on providing product reviews of hardware and software alike. PC magazine, for example, is especially good for this and gives comprehensive reviews of PCs, graphic cards, sound cards, peripherals etc. PC Pro is also a big magazine that gives comprehensive advice on just about all computer-related products. Computer Active is another magazine that is worth a look for technical advice, and provides jargon glossaries, which explain some of the more technical terms.

The product reviews included within such magazines will usually run-through the technical aspects of the hardware or software for you, and then give them an overall rating. For example, with regard to a graphic card, PC Pro will talk about how good the card's technical specifications are and then relate that to the overall value it offers. Performance will be measured, and possibly compared to the top rated products in the category.

Of course, the magazines are not available free. If you want free technical advice, then you could just bypass the magazines via their web-sites! PC Pro has a very good web-site that more than complements its magazine. Visit www.pcpro.co.uk, and you will find that it includes an archive of its reviews, which can easily be viewed. These give the technical specifications of the product, review it, and then provide a rating out of six. With such sites, you can match the reviews to your gift requirements.

CNET.com is also a good site, but does not have an equivalent magazine. This site also provides balanced reviews, with recommendations and general technical advice regarding such gear.

At any rate, although the reviews provided are comprehensive, you might still have further queries regarding the product in question. Further technical advice can be provided from customer service, in places like PC World. They will likely be able to provide an answer to any further queries you might have, regarding the gift you are interested in. For example compatibility issues etc, or whether you have enough hardware resources to run a particular software application.

Computer magazines, the net and IT professionals (usually via customer service) can all provide useful technical advice regarding computer gear. Only you will be aware of your gift requirements, seek out the reviews and advice available and you will be able to break through the technical jargon, which can sometimes confuse.

Bits & Bytes

Bits and bytes are just methods of storing information. The capacity for storing information is quantified by the number of bits or bytes a computer has. However as they are both incredibly small (the smallest form of information is a bit(What's a Byte 2008; Wikipedia January 2008). For Computer Historians: Older computers were encoded in binary. This would give you 2 options, once chosen you would then progress to smaller and smaller “branches” each with an option of 2. A bit is basically one binary stage. It presents you with 2 options This is shown by a string of 0's and 1's(Guinness World Record 2003 150; Wikipedia January 2008). The very earliest computers used holes punched in card or film(Wikipedia June 2008; Kelly June 2008), however now everything is digital) we can use terms such as megabyte, gigabyte and now even terabyte. To avoid confusion later on I have a table illustrating the different relations between these terms at the back.

However most of the terms in the table are not useful, or even feasible, with most computer hard-drives operating in gigabytes and more recently Terabytes(What's a Byte 2008).

Hardware

To begin this section I have got to list the definitions of Hardware and Software and explain the differences.

According to sources 5 & 7 hardware is:

1. Computer Science. A computer and the associated physical equipment directly involved in the performance of data-processing or communications functions. (Answers 2008)
   1. Machines and other physical equipment directly involved in performing an industrial, technological, or military function.(Answers 2008)
   2. Computer Equipment.(Macmillan Dictionary 2002 640)

According to sources 6 & 8 software is:

1. The programs, routines, and symbolic languages that control the functioning of the hardware and direct its operation.(Answers 2008)
2. The programs used by computers for doing particular jobs(Macmillan Dictionary 2002 1337)

As you can see, there is a distinct difference between software and hardware. If you can't (and dictionary definitions are highly opaque) then it basically means that hardware is physical and software is digital. Now data can only be stored on hardware, and can be interpreted in different ways by software. Now basic data storing hardware is, of course, the computer. The computer is used, primarily to store data, and in general you will get the most data into a computer. This is not the only function of the computer but it is an essential one. Apart from the computer there is other hardware designed to hold information. The following list will name useful hardware and its functions.

Floppy disc: now practically obsolete, the largest floppy discs could hold approximately 200MB(Wikipedia June 2008). Although this was high at the time, USB's are no longer manufactured with such a small data capacity.

CD-ROM: Compact Disc- Read Only Memory is the computing version of a CD. Despite a relatively low storage space of roughly 650MB(Kelly June 2008) these are still in common use as there are still some older PC's that will not take DVD's. Cd's are also used for storing music which may be played on both a CD players and on a PC.

DVD: DVD stands for Digital Versatile Disc, although originally it stood for Digital Video Disc(Kelly June 2008). This was due to the fact that DVD's were originally designed for video only, but were adapted to Data storage mediums(Kelly June 2008). With an average of 4.7GB of storage space this device offers the option for high quality data storage, and lots of it.

USB: The Universal Serial Bus is a versatile and easy to carry medium of storage. Also known as Pen Drives, these have been around for a long time. Average USB storage capacity is about 1-2GB(Kelly June 2008) with a maximum of about 16GB(Kelly June 2008)

Blu-Ray: Blu-ray is so called due to the fact that it uses a wavelength of 405nm (Wikipedia June 2008) which produces a violet/blue light (Wikipedia June 2008; Photonic Products 2008) as opposed to the red light that is used to read and write normal DVD's. This allows more data to be stored, and a standard single sided Blu-Ray Disc will store 25GB (Wikipedia June 2008; Blu-ray.com 2008). As this is relatively new technology, it is still not mainstream, but probably will be within 10 years (Kelly June 2008).

External Hard Drive: To explain what this is and its function, I must tell you that in a computer, there are several hard drives. These all store the data. An external hard drive is simply a hard drive external to the computer (Kelly June 2008). These typically hold 150-500GB (Amazon 2008).

HVD: Holographic Versatile Discs are experimental technology. At the same size as a Blu-ray it holds 12 times more information. This technology is in its infant stages and while it currently holds 300GB (Wikipedia June 2008; How Stuff Works 2008) it could potentially hold 3.9TB (Wikipedia June 2008; How Stuff Works 2008).

As you can see HVD when perfected will completely revolutionize the data storage industry. However 3.9TB is so large that it is hard to put it into context.

Digital Storage in Context:

3.9 terabytes is a lot of data. That's so big that it's hard to get your head around how much that is. Well I'll put it into context. If I were to say how many pages that was, it might be easier to picture. All of the pages are A4 sized and are filled with text. There is no formatting and every word is 5 letters long with spaces in-between. There would be 137 298 135 pages (to the nearest whole page). To the nearest million that is 137 000 000. If we take the thickness of a piece of paper to be 0.1mm (Hypertextbook 2001) then the pile would be 13.7km high. That is approximately 1.6 times the height of Mt Everest (Wikipedia June 2008; The Hutchinson Almanac 1998 361)

1 HVD disc could theoretically hold over 1 year of uninterrupted video if MPEG4 ASP encoding is used (Wikipedia June 2008).

Hopefully those two examples should have sufficiently described what a single HVD disc could store.

How it Works:

But how is it possible, for one disc, 12cm in diameter (Wikipedia June 2008) to store so much information? We need to understand the basics of holograms to find out.

Holograms:

To create a hologram, a laser beam is split into 2, known as reference beam and information beam (How stuff works 2008). The reference beam remains unchanged, and the information beam encounters an image. The composition of the light then changes. Then the two beams are superimposed and a 3D image is created.

HVD can store so much more because it is like it is storing 3d information that is overlapping (How stuff works 2008) whereas DVD and Blu-ray store the data side by side (How stuff works 2008). HVD is also more efficient as it stores using “the entire volume of the disc, not just a single layer” (How stuff works 2008).

HVD is not something that will automatically take over the market when it is perfected. Current HVD disc that hold 300GB cost several (6) times more than a double sided Blu-ray Disc to make and hold the same amount of data. In addition, to get a device that will actually play a HVD disc it costs an extra $1000 to make (How stuff works 2008). However with the current technological advances, and with technology prices decreasing, one day we may see HVD dominating the market. One day.

Glossary:

• Bit: Smallest form of computer information.
• Blu-ray: Information storage medium (25GB)
• Byte: 8 bits
• CD-ROM: Compact Disc- Read Only Medium. Information storage medium (650MB)
• DVD: Digital Versatile Disc. Information Storage Medium (4.7GB)
• External Hard Drive: Hard Drive external to computer. Information storage medium (150-500GB)
• Floppy Disc: Informationstorage medium (200MB)
• Hard Drive: Informationstorage medium inside PC. (150-500GB)
• Hardware: Computer Science. A computer and the associated physical equipment directly involved in the performance of data-processing or communications functions.(Answers 2008)
• Hologram: The pattern produced on a photosensitive medium that has been exposed by holography and then photographically developed. The photosensitive medium so exposed and so developed. Also called holograph. (Answers 2008)
• HVD: Holographic Versatile Disc. Informationstorage medium (300GB-3.9TB)
• PC: Personal Computer.
• Software: The programs, routines, and symbolic languages that control the functioning of the hardware and direct its operation. (Answers 2008)
• USB: Universal Serial Bus. Informationstorage medium (1-16GB)

Multitasking - Projecting the impression that it (the CPU) is performing many tasks simultaneously is known as “multitasking”. Modern CPUs contain multiple processing pipelines and the newer CPUs of today actually have multiple processing cores each with its own full complement of multiple processing pipelines.

This latter development (multiple complete processing cores) has indeed given the CPU the capability to perform multiple tasks simultaneously and not merely just seem to be doing so. The way in which processing tasks are managed and distributed among the multiple processing pipelines of the multiple cores is however; still achieved in pretty much the same way that it has always been done.

Multitasking Operating System - When using multitasking operating systems (like Windows, Mac OS X, and Linux etc.) users tend to have multiple programs, utilities and applications running concurrently/simultaneously. For example you may be: editing a word document, downloading from the Internet and listening to music.

In order to be able to do this the CPU will share its processing time among the tasks requiring its attention including user initiated tasks, the operating system, programs, utilities, memory management and quite a few “background” services and routines. It only appears that the processor is doing many things at once because of the incredible speeds that modern CPUs are able to switch between tasks.

Communicating with the CPU - The majority of the subsystems in a PC need to send information to and receive information from the CPU and system memory (RAM). Most also expect to be able to get the CPU's attention when they do so.

In order to improve a computer's overall efficiency the CPU also needs to balance the data transfers between itself and the various other subsystems of the machine. In addition; some of a computer's subsystems such as input/output (I/O) devices and human interface devices, all tend to require “special” attention.

Different Requirements - Another influential factor here is that different devices require different amounts of CPU time at various different irregular intervals.

The mouse; for example, needs far less attention than a hard disk involved in the transference of a large multi-gigabyte file. Thus; in the interest of a more efficient use of a computer's finite resources, it is most beneficial if the amount of CPU time assigned to each device reflects the type of device and the nature of the operation and processing tasks involved.

In the above example of the resource needs of the mouse versus those of the hard drive; more resources can be allocated (even dedicated) to the hard drive for the duration of its current operation(s) while the mouse gets a smaller amount of CPU time.

When the hard drive is finished its current task(s) it may not be required to perform any transactions for various irregular periods of time. The system will then reassign those resources that were being used by the hard drive to other devices and processes as and when required.

Managing Processes - The computer (via the CPU) must also ensure that all active (running) processes and tasks are managed in the most efficient organized manner possible. There are basically 2 ways in which this can be done: CPU polling and device initiated interrupting.

Polling - Polling is the process whereby the CPU systematically locates and asks each device in turn if it requires any help or CPU processing time. This strategy (polling) is a very inefficient process because it is a waste of finite resources.

With polling the CPU is required to continually perform the same tasks (asking each device if it needs the CPU's attention) over and over again. More often than not the device will not require the CPU's attention. Statistically; the most likely answer or result of a hardware polling query is that which it received last time (offer declined).

With polling the CPU will continue to ask each device in sequence the same question ad infinitum. To overcome polling's inefficiency a different strategy; known as “Interrupting”; also referred to as Interrupt Request (IRQ), was developed.

Interrupting - The other way that the CPU (processor) can employ to handle CPU required processes and data transfers is to have the devices requiring the CPU's attention to issue a request for attention as and when they require it. This is the basic concept of interrupt requests.

Thus when a device has data to transfer, it generates an interrupt that says "Mr. CPU I need your attention now, please". The processor then stops what it is doing and deals with the device that requested its attention. Modern CPUs can handle many such requests at a time. In the event of multiple simultaneous interrupt requests the CPU uses a priority system that gives a priority status to interrupt requests based upon the priority associated with the device issuing the request. This is known as Interrupt Request Management.

Supply and Demand - One way of looking at interrupt requests is from a supply and demand perspective. While; having the CPU interrupted all the time may at first glance appear to be an inefficient way to run a computer, when examined closer reality proves otherwise. A large part of the reason is that the modern CPU is literally light years ahead; in terms of speed, when compared to the vast majority of devices conducting transactions with it. To put it into perspective let us consider the following scenario:

Let us suppose that a typist is typing at a rate of 120 words per minute and that on average there are five letters per word. This equates to the typist producing 600 characters of keyboard input per minute. This means that an old 200 MHz Pentium class CPU will process 20,000,000 instructions between each keystroke.

This is why having the processor spend a lot of time asking the keyboard if it needs any help would be wasteful, especially since the typist may at any time you might stop for a minute or two to review the copy, or do something else like make a cup of coffee. In fact; even while handling a full-bandwidth transfer from a 28,800 Kb/sec modem, which of course moves data much faster than the typist's fingers, the processor has over 60,000 instruction cycles between the bytes it needs to process.

Hardware Interrupts - Hardware interrupts such as those mentioned above (typing/keyboard input and modem transfers) are distinguishable from software interrupts by the fact that they generally originate from a device outside the CPU. Table 1 below shows the default IRQs in order of descending priority.

Software Interrupts - There is another type of interrupt that occurs in modern PCs; known as software interrupts. These are generated by the operating system, programs and various other software applications and are used by various software programs in response to different events that occur as the operating system and applications run.

In essence a software interrupt represents the CPU interrupting itself (as the interrupt originates from within the CPU) and is part of the reason of how the CPU is able to do many things at once.

Basic Input/Output System (BIOS) - A computer's BIOS provides various software routines (subprograms) that can be called by higher-level software such as DOS, Windows, or their applications, to perform different tasks. This includes actions like reading and writing from the hard disk, processing information received from devices, etc.

BIOS Access - Another performance enhancing functionality that software interrupts make possible is facilitating system software (DOS or the operating system), applications and other software to directly access one another via BIOS routines without having to know where the target application resides in memory.

Interrupt Vector Table - Normally, to call a software routine you need to know its address (location) in memory. However; with interrupt requests a table called an interrupt vector table is created and this is used to bypass the need to explicitly know the correct address in memory. Now every time the system is booted, the BIOS puts addresses representing where its routines are located for each interrupt that it is configured to respond to.

So whenever DOS, the operating system or other applications want to use a BIOS routine, it generates a software interrupt. The system processes the interrupt, looks up the value in the interrupt vector table and then automatically jumps directly to the appropriate BIOS routine. Modern operating systems and applications as well as DOS can also directly use this interrupt vector table.

BIOS Bypass - More recently newer operating systems bypass the BIOS totally as this does help improve system performance.

BIOS Assigned Logical Names - The BIOS assigns logical names to devices based on their IRQ number and memory address. For example:

IRQ 3 and I/O address 2F8-2FFh becomes Com2.

Legacy Devices Default Settings - For older systems; such as those based around the ISA bus, it is often the case that the default IRQ assignments must be preserved. This necessity is most common with older software and games that require the ISA SoundBlaster sound card to be accessible using the following configurations:

IRQ 5, I/O Address 220h and DMA 1

Failure to comply will result in; at best no in game sound and at worst no game at all.

Interrupt Summary - In short; interrupt requests are a mechanism that allows the various devices and software that make up a computer to jump the processing queue in order to have tasks of a predetermined “higher” priority to be executed “out of turn”. BIOS services are accessed using software interrupts, which are similar to the hardware interrupts except that they are generated inside the CPU by programs instead of being generated outside the CPU by hardware devices.

The hardware on a network may include: personal computers, mainframes, supercomputers, printers, fax machines, navigational control systems, and interactive entertainment centers.
The software on a network always includes application software, workstation operating systems, and network operating systems.

Networked computers have a number of advantages. They allow information to be exchanged at high speeds, they allow important devices to be shared, and they allow people to connect to their computers over long distances.

Benefit of Networking

Geographically remote areas can be connected to share information. Without actually transferring the entire file to all people involved, several people can simultaneously share large files. Also within a networked environment the information generated by a single user can be shared worldwide instantaneously. This enables faster, more precise communication which should translate into greater accuracy, productivity and cost savings.

• Networking allows different types of computers to communicate. Mac and PC users can share information and resources over a network.
  
• Users on a network can also share physical resources such as scanner, printer, or other expensive piece of hardware. Sharing hardware significantly reduces the expense of running a system.
  

Local Area Network (LAN)

1. Limited to a small geographical region
   
2. Specifically designed to share hardware and software at high speeds.
   
3. Originally developed to connect mainframes to dumb terminals (keyboard and monitor only-no system unit) over 50 years ago.
   
4. Mainframe LANs are faster, more powerful and have higher storage capabilities, while PC based LANs are more flexible to changing environments
   
5. Many companies used a combined network of mainframes and PCs
   
6. Computers
   

How to Draw a Circle

As a mathematical description, circle is a combination of points with the same length from a fixed point. To draw a circle, two things we need. They are the coordinate of center of the circle and radius or diameter of it. Let's now draw our first circle by Solidworks. Let's draw a circle with a center of origin and a radius of 20 mm.

1. Click the sketch button to define a plane on which you will draw. Since our drawing is 2D, any plane can be chosen. I choose top plane as a reference plane.
2. Click the circle button on the toolbar and choose origin as the center point of the circle. Afterthat, drag the circle to the out of the page.
3. By clicking "smart dimension" button , dimension the radius of circle. Since the radius is 20 mm, specify diameter as 40 mm.

How to Draw Filleted Arcs

To draw filleted arcs, we first need a corner of two intersecting lines. As an example, we will filet one corner of 40x40 mm square. Lets first draw the square by using rectangular button on the toolbar.

1. Click the fillet button on the toolbar.
2. Enter the radius of fillet as 5 mm into the fillet parameters space.
3. Choose the corner point which you want to fillet. Be careful here, you should select the point not the sides you want to fillet. After that, Solidworks automatically dimension the filleted arc. Here is the result.

Above all, we will use sketch command to define a planes. Simply pressing sketch button in Solidwork menu, you can define a plane on which you want to start drawing. Basically, one has three alternatives, front, top, and right respectively. For 2D drawings, one can select any of them. In our tutorial set, I will select top plane as a reference plane. This means, I'll draw on the top surface of imaginary rectangular prism. Think like this for simplicity.

 

How to draw a line

To draw line, simply click the line figure on the toolbar. Solidworks will present you four alternatives to draw line. They are "as sketched", "horizontal", "vertical" and "angle". Lets we draw a vertical line with a height of 60. Click the "vertical" radio button and  and somewhere on the screen and drag the tip of cursor vertically. This will draw a vertical line. To dimension it, click "smart dimension" button and starting point of line. Then drag the tip of cursor to the end point of vertical line. Solidworks will ask you the numerical length of the line. Write 60 into the space. Now, you have a vertical line with a length of 60 mm.

How to draw a rectangle

To draw rectangle, click the rectangle figure on the toolbar. Then draw a rectangle with any lengths. Then dimension it by using "smart dimension" button. Dimension each side of rectangle. Let's draw a rectangle with a side length of 120 mm and a height of 80 mm.