Computer Hardware Tutorials
PC Computer Notes has been designed as a free introductory level, online computer training course, providing tutorials on computer hardware, software, operating systems, and basic troubleshooting.
If you just want to learn more about your computer's hardware, software and the overall system, here's a good place to start! Read the tutorials, then try the exercises provided. If you have trouble with the review questions, go over the tutorials again. You'll be surprised at how much you learn!
The computer hardware tutorials, labs and review questions may also be helpful for those preparing for Comp TIA A+ A plus Certification exams If you're looking for study material for your Comp TIA A+ A plus computer technicians exam, PC Computer notes' tutorials can be used as a source for pre-exam study.
Although the review questions may not be exactly what's on the test, they are designed to cover the information provided in the tutorials and emulate the type of questions that you'll find on the A plus exam. I do still have companies offering software for evaluation. I also have some interest from former subscribers that are interested in writing articles. So, I may make an attempt to get the News Letter back up, with perhaps a different format, if there is enough interest. Check back this summer! New subscriptions will not be accepted before that. Until then, a few of the old are still available.
My Computer
Aside from a little information on binary and hexadecimal numbers, this section deals mainly with the parts of your computer you can see at your desk.
Starting with the computer case, we'll discuss it's role concerning the actual expandability, protection, and lifetime of your system. We'll go on to include the different types, sizes, and form factors available and what you need to know before you purchase.
Next, you'll learn about some of the peripherals such as monitors, keyboards and the mouse. Different kinds, how they work, care and maintenance and possibly some simple troubleshooting methods are covered.
Before learning a little about binary and hexadecimal numbering systems, we'll look at the different ports and connectors on the back of your computer. What's a DB-9 connector? What's a Parallel Port connector? What's it used for? It's not that difficult! It just seems a little intimidating at first. Just click on the link below to start your tutorial.
Inside the computer case
Some people get a little excited when they look inside a computer and see all the different electrical components and circuit boards. All the wires, connectors and data cables inside tend to be a little intimidating. Yet, all of today's computer repairs, replacements, upgrades and installations are getting easier and easier.
A technician could spend hours (at outrageous prices) to search for a specific chip or failed solder connection that's causing a particular problem. Repairs aren't done at the chip level anymore. Everything is very modular. It's quicker, easier, and much more economical to have the technician pop in a whole new video card or motherboard.
It's still important to know some of the different components and what they do. It can give you an insight as to which particular module may need replacement, and aids in the troubleshooting process.
It may only take 5 minutes to replace a particular FRU (Field Replaceable Unit), but it might require a lot more time to troubleshoot the problem and discover which module needs replacement.
Even if you don't plan on becoming A+ (A Plus) Certified, if you've come this far you must have an interest in computers. This is a great place to learn about what's inside that case.
Start this section with ESD (Electrostatic Discharge) precautions and work your way through in order. Once you understand ESD and the precautions you should take, go ahead and open the case. See if you can find the different components, connectors, and devices discussed. When you do, try and discover everything you can about it. What kind of chip is it? What does it do? What kind of socket does it fit into? How much data can it move at once? How fast is it?
If you have room on your desk, you can run your computer with the cover off * so you can look inside as you read (keep your hands out).
*Note: Only run your system with the cover off for a short period of time. Contrary to popular belief, leaving the cover off can interrupt the airflow, actually contributing to overheating in some cases. For short periods of time it should be OK. In fact, its often necessary when troubleshooting hardware. Its also a good time to make sure the CPU fan is working properly!
By the time you're done, you'll be removing and reinstalling some of the devices inside.
Look around for an old 286 or 386 computer. They can be picked up for less than 50 dollars, in working condition. Whether it's working, or not, you can learn an awful lot by taking it apart and putting it back together
Operating System
The Operating System (OS) is an integral part of your computer. It acts as an interpreter between the different application software programs and your computer. The OS can understand the data, information and commands used by different programs because those programs are written or coded specifically for that Operating System's interface, using it's standard rules, commands and protocols. It then translates the many commands and information into procedures the computer can understand. Computers are not of much use without an operating system.
Just a quick note on Operating Systems. As I said before, your computer will not work without one. The accepted practice in most stores is to sell computers with operating systems.
Recently, I was buying a computer for a customer and one particular store had prices considerably lower than others. Of course, there were the usual price cutting features, smaller hard drive, cheaper video card, less RAM, etc..., but it would serve the purpose. They offered the choice of Windows98 or 2000, which was really nice of them... considering the fact that you had to buy it off the shelf!
If you wanted an Operating System with your computer, it was going to cost you extra!
Make sure of what you're getting
Tips & Tricks
Tips & Tricks can often be an interesting, fun and fast way of learning a particular software. As far as understanding the computer and its operating system, everybody is at a different level. And everyone is always learning. There's so many different ways of performing the same function in a single operating system that its impossible to know them all. The OS has become so huge and intricate that even a person considered an expert couldn't possibly be aware of all the capabilities of today's Operating Systems (let alone the thousands of applications out there).
Many of the Tips & Tricks presented on this Site may be fairly basic, but as I said before, everyone is at a different level. Other tips may not be so common. I'll continue to add them when I have time or as they come up.
The Tips & Tricks found on this site are gathered from experience, magazine articles, e-zincs, other websites and reader submission. If you have a favorite that you'd like to share with other readers, please send it to us.
Network Services
In this lecture we study computer networks.
We use a top-down approach, starting with applications. We present an overall picture, which will enable you to understand the layered model of networking software. Then in the following chapters, we will study the various components (called “layers”), one by one.
What are computer networks used for ?
Computer networks allow people and machines to communicate, using a number of services. The slide shows a small subset of services.
Network Infrastructure
A computer network is made of two distinct subsets of components- distributed applications are programs running on interconnected computers; a web server, a remote login server, an e-mail exchanger are examples. This is the visible part of what people call “the Internet”. In this lecture we will study the simplest aspects of distributed applications. More sophisticated aspects are the object of lectures called “Distributed Systems” and
“Information Systems” the network infrastructure is the collection of systems which are required for the interconnection of computers running the distributed applications. It is the main focus of this lecture.
The network infrastructure problem has itself two aspects distance: interconnect remote systems that are too far apart for a direct cable connection meshing: interconnect systems together; even in the case of systems close to each other, it is not possible in non-trivial cases to put cables from all systems to all systems (combinatorial explosion, cable salad management problems etc.).The distance problem is solved by using a network, such as the telephone network with modems (see later). The meshing problem was originally solved easily because the terminals were not able to communicate with each other, but always has to go through a main computer. The mesh in such cases is reduced to a star network. Today this is solved by a complex set of bridges and routers.
(Physical Layer & Data Link Layer)
The objective of this and the following slides is to introduce the concept of layers. Like any complex computer system, a network is made of components. This decomposition is, to a large extent, stable: computer networking people have agreed on a reasonable way to divide the set of functions into what is called “layers”.
We use the term layer because the decomposition always assumes that different components can be ordered such that one component interfaces only with two adjacent components. We call “layers” the components. We start with the simplest, and the oldest network example: it is a mainframe connected to terminals. In this case, there are mainly two functions
• physical layer: translates bits into electromagnetic waves;
• data link layer: translates frames into bits.
These two functions are implemented on cables or on radio links. The physical layer has to do with signal processing and coding; it is the object of the lecture called “Telecommunications”. The data link layer has to do with bits and bytes; we will study the data link layer in this lecture.
What is a Network
Modern networks have more than the physical and the data link layers. The network layer is a set of mechanisms that can be used to send packets from one computer to another in the world. There are two types of networks: With packet switching, data packets can be carried together on the same link. They are differentiated by addressing information. Packet switching is the basis for all data networks today, including the Internet, public data networks such as Frame Relay or X.25, and even ATM. Packet switches have queues. Circuit switching is the way telephone networks operate. A circuit emulates the physical signals of a direct end-to-end cable. When computers are connected by a circuit switched network, they establish a direct data link over the circuit. This is used today for modem access to a data network. Modern circuit switches are based on byte multiplexing and are thus similar to packet switches, with the main difference that they perform non-statistical multiplexing.
A network has intermediate systems (ISs): those are systems that send data to next ISs or to the destination. Using interconnected ISs saves cable and bandwidth. Intermediate systems are known under various terms depending on the context: routers (TCP/IP, AppleTalk,…), switches (X.25, Frame Relay, ATM, telephone), communication controllers (SNA), network nodes (APPN)
