Familiarization with the computer

Purpose Of This Module

LEARNING OBJECTIVES:

BACKGROUND & DISCUSSION

INSTRUCTIONS:

EVALUATION CRITERIA:

The completion report processor is Under construction

Learning Objectives ---- What do we hope to accomplish here?

The flow of data through the computer is an important aspect of understanding how the computer works and how to find problems when they occur. In this exercise you will demonstrate your understanding of the form and the direction of data flows through the computer under normal operating conditions.

Each component of the computer has its own unique purpose. Think of it, if it weren't unique you'd already have one of them so why would you need another? It isn't quite that simple, of course. You need more than one bit of memory and more than one disk drive. In this exercise we will study then you will show your competence in the computer and its components as 'black boxes'. That is the old engineering concept that if you know a component's inputs, outputs, and rules of translating inputs to outputs then you know enough about the component to use it. You will be able to apply the black box principle to the following:

• The computer itself
• Computer peripherals (printers, plotters, etc.)
• Keyboard
• Mouse
• Screen
• Floppy disk drive
• Hard disk drive
• CDROM
• Power supply
• Mother board
• Memory subsystem (ROM & RAM)
• Case & front panel

The computer is just a tool. It is not an end in itself. By running various kinds of software: off the shelf applications or proprietary programs, you can make the computer do what is needed. Of course, you've used a computer extensively before, but we need to make sure you understand the operation of the computer in real world environments.

Data flows within the computer
1. The computer and its components as black boxes -- What is available today?
2. Safety for the beginner in the lab
3. Using the computer with representative software

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Background & Discussion ------ Some help in getting started. Why is this important?

The engineer's black box concept  recognizes the fact that everyone can't know everything about any complex system. The 'black box' means that it is closed to inspection. Not only can you not see into it, you don't need to look into it to know how to use it. You do have to know what you can do to it (the guzintas or inputs) and what it can do to or for you (the guzoutas or outputs). You know the keyboard as a black box. The inputs are keypresses, the outputs are electrical pulses to the computer telling it, in its own language, what you've typed in. The rules of operation (often called 'transfer functions', designs, or programs) simply identify how you can expect the translation to be made.

You don't have to know what all those transistors, capacitors, and thingamabobs are actually doing in there to use it. Of course, the time may come when you have to repair a keyboard and what is inside becomes important. No problem! You can simply apply the black box concept to the sub components of the keyboard. Taking them one at a time, looking at their inputs, outputs, and rules, you can understand what's inside the bigger box. (which is no longer black since you can see inside it)

I'm not going to explain the computer to you here. We will discuss it in class. You will find it in the textbook and other reference books. You will play with the components and investigate their operation. Here are some topics you will need to investigate in some detail:

• The CPU
• The Bus that interconnects the components electronically
• The memory (ROM and RAM) into which we put programs and data
• The programs themselves--- How do they actually cause things to happen?
• The I/O or Input/Output section--- How the computer interacts with you.
• Hard and floppy disks and disk drives
• The disk controllers
• By the way, just what are those card connectors on the mother board?
• How can we just plug cards in and expect them to work?
• Video adapter cards and monitors
• How do they work?
• What kinds are available? What are their features?
• Exactly what does the power supply do? What are each of those cables?
• The Mouse: How can it control that little arrow on the screen?
• What is the mouse driver?

Expansion cards

If all important features were on the motherboard, when you buy a computer you won't be able to expand it much. Relying on expansion slots for functions like drive controller and video interface allows expansion beyond initial capability. On the other hand, it is cheaper to put the functions on a mother board than to use separate expansion cards for these functions. If a major breakthrough occurs that makes your current video card obsolete you can just buy one of the new configuration and grow with the technology. If it is on the motherboard you are stuck with the obsolete interface. So there is a trade-off between initial expense and expandability. The trade-off needs to be made for each purchase.

The expansion slot is a very sophisticated approach to building a computer. Each slot connects its card to the data, control, and address buses and allows the card to interact in standard ways. Since all slots and cards are mutually compatable, many companies are making the cards, competition keeps the costs down. The constant pressure to beat out the competitor assures a constant flow of new and better expansion cards at reasonable prices. Cards and slots range from simple 8 bit to 16 bit and 32 bit cards. ESA, EISA, Local bus, PCI bus, are terms often used. You should know what all these terms and factors mean.

The expansion cards often need access to I/O addresses, DMA channels, and IRQs (Make sure you know what each of these terms mean). When installing a new card you will have to make sure that there isn't a conflict. Documentation with the cards don't always give complete instructions for avoiding conflict.

Memory

How much memory? That's easy to answer. How much can you afford? Now that it's getting cheaper, don't get caught short.
 

Computer Buses

The bus, of course, is the primary thoroughfare for moving data from one place to another within the computer.  For example, from an input port to the registers, from memory to ALU, and from peripheral devices such as hard drive into the system.  In the beginning of the PC there was the standard 8 bit bus.  That has grown and grown over the years until now the PCI bus is dominant as an internal bus.  We also have IDE, SCSI of various levels, the fire wire, and USB.  You should becom familar  with these bus types.  Each has its pros and cons.
 

1. Know what you are doing. ..... Gee, if you follow rule 1 you don't need the others after all.

Beware of electrical components. Most of them are low voltage and can't easily kill you but they can be dangerous. Don't reach in and touch any hot circuit. Turn off and unplug things before you start to take them apart.

Remember you can hurt the computer parts very easily.

You can pick up a static electric charge on your body which will discharge to any convenient conductive object near you. (a doorknob, another person, a computer) A one-inch spark took 25,000 volts of charge potential. Computer components are designed for 3, 5, or 15 volts. 20 volts can kill them, think what 25,000 volts can do to them. Talk to me about static electric protection.

• Grounding yourself
• Static reduction bags

Computer components: We will also discuss these as we disassemble and reassemble a computer.

Software: You should be very familiar with applications and the use of operating systems already. I will expect you to use word processors, spreadsheets, and one or more operating systems. You should be able to install an application on a computer. If you are unsure about any of this talk to me and I'll schedule time to bring you up on the curve. 

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Exercise Description -------- Procedures for completing this exercise

1. Working in pairs or in threes, demonstrate to your partner that you can set up a computer, connect the required cables to the monitor, printer, mouse, and computer and make it work. Demonstrate an understanding of the operating system (DOS, MAC, or windows) sufficient to run a word processor and a spreadsheet. Assure that you can create a document with each, save the file. Transfer the file to another disk or subdirectory. Display the subdirectory tree and explain what it means.
2. Using the Web as your resource, create a section in your notebook that lists the parts needed to build a custom computer.  Include the most useful options for each component.  Cost out the configuration you choose.  Include this information in your presentation.
3. Attend the lecture/discussion on memory upgrades.
4. Using a working computer assigned by the instructor, perform the following:
• a. Check the system out thoroughly.
• b. Carefully disassemble the computer down to its component parts including the memory.
• c. Verify that you have the correct memory for this computer
• d. Carefully remove existing memory.
• e. Install the new memory.
• f. Reassemble the computer
• g. Check out the system
• h. Assure that all operating parameters are correct.

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Evaluation Criteria

1. Participation in discussions: Did you---

• come into the discussions prepared?
• Contribute to the discussion?
• interact well with the other students?
• Did you summarize well when asked?

• Were your training aids, graphics well done? (appearance)
• Were they representative and helpful? (content)

7. Safety: Were you able to clearly show that you understand the rules as they were presented? 

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