SPRUCE CREEK SOUTH COMPUTER CLUB
1. Introduction
This is a beginning class that will provide the student with an introductory visual and hands-on experience of having a computer disassembled and having each part explained and passed around for inspection. The software operating system will also be discussed.
2. Objective
That each student should become familiar with the internal workings of a personal computer.
3. Components of the System Software
The system software is Windows. This software provides the user with an easy to use set of tools to provide an interface with all the input and output devices connected to the system such as the keyboard, scanner, monitor, and printer. The operating system program acts as a traffic cop between the input and output devices and the application programs.
4. Components of the Hardware System
A. External Components
The keyboard is an input device.
There are both serial and PS2 connections for a mouse. The mouse is an input device for positioning the cursor on the monitor.
The monitor is an output device that presents graphics on the screen.
The scanner is a device that allows you to input photos or graphics into various graphics programs. At the right there is an artist’s rendition of a scanner.
The printer is an output graphic device for creating text and documents.
The mike and the speaker provide for input and output sounds for the computer.
Video cameras are usually mounted on the monitor and provide visual input for videophone programs. Digital cameras are just like film cameras except they provide Digital graphic images suitable for input into photo programs.
Backup devices such as tape drives, zip drives, and CD/RW drives are used as output devices to save the Operating System programs, application programs, and data.
This unit converts the 110AC power from the wall outlet to assorted DC voltages for the various components inside the system. The unit is usually equipped with a fan for cooling the voltage conversion components such as a transformer, diodes, and resistors.
C. Motherboard
The circuitry today on the motherboard operates at 100 to 400 megahertz (1 millionths of a second). The motherboard circuitry connects the processor, memory, and input/output ports slots for the Adapter cards. The motherboard circuitry contains the following components:
This stands for Read Only Memory. The programs contained in read only memory work in conjunction with the boot sector and other programs on the disk to provide access to Windows.
This is also a storage component. Information such as instructions from Windows or a program is store here to be executed by the Processor below. This is done because memory is much faster (thousands of times) than a disk. Memory operates at the rate of nanoseconds (1 billionth of a second). It is important to note that there are many different sizes, capacities, and speeds of memory components. Be sure you have the proper part number when replacing or adding memory.
This is the heart of the PC. This component executes the functions (operations such as logic, math, data moves, and input/output). Some processors are the Pentium II, Pentium III, and the Celeron. These processors internally operate at many times the speed of the motherboard circuitry (500 to 1000 megahertz).
CMOS stands for Complementary Metal-Oxide Semiconductor this is a low-power semiconductor technology commonly used in personal computers to hold basic start-up information such as how much memory, physical attributes of the hard disk and floppy disk drives and the systems clock that keeps the time of day and calendar. CMOS retains this storage through the use of a battery to allow the information to be retained between power off and power on. These batteries should be replaced about every three years. Pay particular attention to the size, shape and voltage when replacing these batteries.
This stands for Universal Serial Bus you can daisy chain as many as 127 peripherals off one USB port and use them all at once. This is a new connection for the PC (it has been used for years on the MAC). It operates similar to the serial connection described above, and is used to connect devices such as printers, scanners, and digital cameras. The advantage of this connection is that it is fast (12 megabits per second).
The Adapters provide many of the hardware functions that are contained in the PC. The Adapter cards are plugged into the motherboard. The plugged connection is called the bus. There are a number of buses in most of the moderately new computers: 1) PCI that stands for Peripheral Component Interconnect and is technically a very fast bus. 2) ISA stands for Industry Standard Architecture and has been around for a long time. It is slower than PCI but is retained for its compatibility. The buses connect the Adapters to the circuitry and the processor on the motherboard. We will discuss that circuitry and the processor later. The Adapter cards usually provide the following functions:
This Adapter connects to the monitor at the blue plug connection above, and provides the intelligence for the various screen settings that you can set with Windows in the Display Properties dialog box like the following screen resolutions: 1024 X 768, 800 X 600, and 640 X 480.
This Adapter provides for the connection of serial devices, such as external modems, scanners, PC card readers, and parallel devices such as printers, and game devices such as joysticks. The manufacturers of newer systems have included the functions of this Adapter as part of the functions of the motherboard.
This IDE (Integrated Device Electronics) Adapter provides for the circuitry to read and write information from the PC’s memory to the hard disk, CD, and your floppy drives. The information contained on the hard disk includes the Windows System program, application programs, and user data such as pictures, spreadsheets, emails, and letters.
The information on the floppy disks usually contains user data, but occasionally they contain programs. The CD contents are described below.
This SCSI (Small Computer System Interface) Adapter also provides for the circuitry to read information from the CD and write it to the PC’s memory. The CD is a read only device. The CD’s usually contain Windows drivers (programs that interface between the services of Windows and the devices connected to the system). On the SCSI Adapter multiple devices can be attached like Christmas tree lights (on one connection). The SCSI Adapter can also be used for some types of Hard Drives.
This Adapter provides the circuitry and dialing functions dial and convert the signals from a remote MODEM such as an AOL server (remote computer) to a program that goes "online" such as the AOL program in your PC. The picture on the left shows the internal modem adapter card in the upper left, the external modem in the lower center, and the PC modem card for laptops.
This device is comprised of one or more spinning magnetic platters upon which is written data in one form or another by magnetic heads mounted on arms which are mechanically controlled to position themselves in many positions or cylinders across the disk surface. A hard drive capacity today is measured in gigabytes (a 1000 million bytes (characters)). The hard drive also contains the boot sector program that allows the system to finally get to Windows. The hard drive operates in milliseconds (1 thousandths of a second).
This device is similar in the mechanics of its big brother (the hard drive above) except that its storage capacity is much smaller (1.4 million bytes or 800 times smaller).
This device provides for the reading of both data (programs) and music CD’s.