The main part of a personal computer. The system unit includes the chassis, microprocessor, main memory, bus and ports, but does not include the keyboard or monitor or any peripheral devices.
SYSTEM UNIT
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| System unit, the actual computer |
- The system unit, also known as a 'tower' or chassis' is the main part of a desktop computer. It includes the motherboard, CPU, RAM and other components. The system unit also includes the case that houses the internal components of the computer.
- The term "system unit" is often used to differentiate between the computer and peripheral devices, such as the monitor, keyboard and mouse. For example, if a repair shop asks you to bring in your computer, it may be unclear whether you need to bring your monitor and peripheral devices as well. If you are told to just bring your system unit, it is clear you only need to bring the computer itself.
- Some modern computers, such as the iMac, combine the system unit and monitor into a single device. In this case, the monitor is part of the system unit. While laptops also have built-in displays, they are not called system units, since the term only refers to desktop computers.
SYSTEM UNIT TYPES
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System unit
ELECTRONIC DATA AND INSTRUCTIONS |
- Data and instructions are represented electronically.
- Two state system or Binary System
i) off/on electrical states
ii) Characters represented by Os (off) and 1s (on)
iii)Bits
iv)Bytes
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| Binary System |
- So the reason behind the usage of binary system is because the transistor can only be turned on and off. But then I think, why can’t there be the states on and off and 8 interstates for each transistor? Why can’t they be half-on or quarter-on or 1/10-on, for example? The mechanism for these interstates could be by varying the amount of current that pass through the transistor and by using resistor, each individual states can be detected for each transistor.
- If we have 8 of these interstates plus complete on and complete off, then we can have a decimal system instead of a binary system. Instead of having to code everything into 0 and 1 for processing, they can now be represented by 0, 1, 2, 3, 4, 5, 6, 7, 8, and 9. This would certainly decrease the number of combinations required to represent all the different bits of information.
- Instead of having to process millions of instructions in binary to view this page, the amount of instructions may as well be reduced to only hundreds of thousands. When less instructions is required for one task to be performed, then the processor can perform much more tasks in a given time. A 3.0GHz processor today might as well be equivalent to 15.0GHz if it’s operating in decimal system instead of binary.
CHARACTER CODING SCHEMES
ASCII : As-key, stands for American Standard Code for Information
Interchange
EBCDIC : Extended Binary Coded Decimal Interchange Code
Unicode : Family of 16-bit codes that support both ASCII and EBCDIC. It is also used for international languages like Chinese and Japanese. These languages have too many characters to represented by the eight-bit ASCII and EBCDIC codes.
SYSTEM BOARD
- Also known as the motherboard. The system board control communications for the entire computer system.
- Acts as a data path and traffic monitor, allowing the various components to communicate efficiently with one another.
- External devices such as the keyboard, mouse and monitor could not communicate with the system unit without the system board.
RAM
Random Access Memory or RAM most commonly refers to computer chips that temporarily store dynamic data to enhance computer performance. By storing frequently used or active files in random access memory, the computer can access the data faster than if it to retrieve it from the far-larger hard drive. Random access memory is also used in printers and other devices. Unlike ROM, RAM is a volatile memory and requires power; if power is lost, all data is also lost. Below is an example image of a 512MB DIMM memory stick. |
There are several different types of random access memory chips which come several to a "stick." A stick of RAM is a small circuit board shaped like a large stick of gum. Sticks of RAM fit into "banks" on the motherboard. Adding one or more sticks increases RAM storage and performance.
ROM
Short for Read-Only Memory, ROM is memory that is capable of holding data and being read from; however, it is not capable of being written to or having its data modified. Unlike RAM, ROM is non-volatile and capable of keeping its contents regardless if it has power or not. A good example of PROM is the computer BIOS as shown in the example picture to the right.
Type of ROM
ROM memories have gradually evolved from fixed read-only memories to memories than can be programmed and then re-programmed.
The advantages of ROM are:
- They are non-volatile
- They are cheaper than RAM
- They are static and do not refreshing
- They are more reliable than RAM as their circuit is simple
- They are available in longer sizes than RAM
- They are easier to interface than RAM
Given that ROM are much slower than RAM memories (access time for a ROM is around 150 ns whereas for SD RAM it is around 10 ns), the instructions given in the ROM are sometimes copied to the RAM at start-up; this is known as shadowing, though is usually referred to as shadow memory).
FLASH
Flash memory refers to a particular type of EEPROM, or Electronically Erasable Programmable Read Only Memory. It is a memory chip that maintains stored information without requiring a power source. It is often used in portable electronics, like MP3 players, and in removable storage devices.
How Flash Memory Works
We store and transfer all kinds of files on our computers -- digital photographs, music files, word processing documents, PDFs and countless other forms of media. But sometimes your computer's hard drive isn't exactly where you want your information. Whether you want to make backup copies of files that live off of your systems or if you worry about your security, portable storage devices that use a type of electronic memory called flash memory may be the right solution.
Electronic memory comes in a variety of forms to serve a variety of purposes. Flash memory is used for easy and fast information storage in computers, digital cameras and home video game consoles. It is used more like a hard drive than as RAM. In fact, flash memory is known as a solid state storage device, meaning there are no moving parts-everything is electronic instead of mechanical.
Here are a few examples of flash memory:
- Your computer's BIOS chip
- CompactFlash (most often found in digital cameras)
- SmartMedia (most often found in digital cameras)
- Memory Stick (most often found in digital cameras)
- PCMCIA Type I and Type II memory cards (used as solid-state disks in laptops)
- Memory cards for video game consoles
Flash memory is a type of EEPROM chip, which stands for Electronically Erasable Programmable Read Only Memory. It has a grid of columns and rows with a cell that has two transistors at each intersection.
Expansion Slots & Cards
Alternatively referred to as an add-on card,internal card or interface adapter, an expansion card is an electronic board or card added in a desktop computer or other non-portable computer to give that computer a new ability, such as the ability to connect to another computer using a network cable. Below is a list of expansion cards that could be installed in an available expansion slot.
There are alternative terms used for an expansion card. It is also known as expansionboard, add-on card, interface adapter or an internal card. Generally, around one to sevenexpansion cards can be installed into the desktop computer system. Laptops do not use standard cards due to their small form factor. A laptop expansion card can be in the form of a removable PCMCIA card that offers additional functionalities to it.
The examples os slots & cards:
Express card slot
Commonly Used Expansion Cards
- Video cards
- AMR Advanced Multi Rate Codec
- Sound cards
- Network cards
- TV tuner cards
- Video processing expansion cards
- Modems
- Host adapters such as SCSI and RAID controllers.
- POST cards
- BIOS Expansion ROM cards
- Compatibility card (legacy)
- Physics cards. (becoming obsolete as they are integrated into video cards)
- Disk controller cards (for fixed- or removable-media drives)
- Interface adapter cards, including parallel port cards, serial port cards, multi-I/O cards, USB port cards, and proprietary interface cards.
- RAM disks, e.g. i-RAM
- Solid-state drive (becoming obsolete to SATA Rev. 3.0, SSDs)
- Memory expansion cards (legacy)
- Hard disk cards (legacy)
- Clock/calendar cards (legacy)
- Security device cards
- Radio tuner cards
TV TUNER CARDS AND VIDEO CLIPS
TV tuner cards are the latest hardware option for the media-savvy. With most TV tuners, you can watch over 100 TV channels of high-quality television, rent online movies, and even plug in S-video or composite hardware. Most cards come with remote controls too, and Vista Ultimate and Home Premium come with Media Center, which allows you to surf through TV channels just as if you were sitting in front of an actual television. You can even schedule and record TV programs, and zoom in, pan, or freeze video action.
HOW TO INSTALL?
Meeting System Requirements and Installing the Card
There are specific system requirements for all hardware products, and TV tuners are no exception. For the most part though, if you have Windows XP on a new machine, you’ll probably meet those requirements easily. However, you should make sure by reading the information on the box very carefully. If you need to upgrade something, say RAM or the video card, do so before continuing.
Open the case. As with installing any card, make sure you are properly grounded, and then seat the card into the proper PCI slot. Press firmly and secure the card with a screw. Again, by reading the manufacturer’s instructions you can make sure you do this properly. Some may require the card be placed in the last slot, away from the other cards, and some may require just the opposite. Once installed, close the case, and start the PC.
Latest Drivers for WinTV-USB, WinTV-USB-FM and USB-LiveNote: the operation of WinTV under Windows requires two pieces: a WinTV driver and a WinTV application (the WinTV application is available below in "Latest WinTV Application" section). You cannot run the application without loading the driver. | ||||||||||||
Latest driver for the WinTV-USB, WinTV-USB-FM and USB-Live for laptop and desktop PC's using USB 1.1 or USB 2.0This driver will remove and replace any older WinTV-USB driver. Installation instructions: 1. If you are upgrading from an older version of WinTV-usb, run HCWCLEAR.exe to remove the old version. 2. Download this file (usbdrv262) and save it to a directory you will remember (for example: C:\) 3. Run usbdrv262. This will unpack the driver and start the driver installation. You do not have to remove the WinTV-USB. 4. Halfway through the installation you will be asked to Reboot. Do so to continue the driver installation. 5. After rebooting, Windows will display a "New Hardware Found" message, and then go on to install this updated driver. 6. Now, download and install the WinTV application (see below). | ||||||||||||
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Latest WinTV2000 application with the new user interfaceTo install, copy this file to a temporary directory on your local disk. Then run wintv2k40_21126.exe, which is the installation program for the WinTV application. New features: This version of WinTV2000 has new, bigger buttons for 'Always-on-top' and 'Full screen'. There are also easier to get to menus. New features: This version now includes integrated video clip and hi-resolution still image capture. New features: This version now includes the WinTV32 and WinTV2000 applications. Installation instructions: 1. Download this file (wintv2k40_21126.exe) and save it to a directory you will remember (for example: C:\) 2. Run wintv2k40_21126.exe. This will unpack the driver and start the driver installation. Name: wintv2k40_21126.exe Version 4.0 size=2468K Updated May 6, 2003 | ||||||||||||
WinTV Radio32 application version 1.52 | ||||||||||||
To install, download to a temporary directory and run RADIO32.EXE New features include 30 presets and local/distance reception. Also, name radio stations by creating a preset and then clicking on the freq display and typing in the string you want. File name: radio32ver152_20311.exe Version 1.52 size=324K Updated Nov. 7, 2002 | ||||||||||||
Plug and Play
In computing, plug and play is a term used to describe the characteristic of a universal computer bus, or device specification, which facilitates the discovery of a hardware component in a system, without the need for physical device configuration, or user intervention in resolving resource conflicts.
Plug and play refers to both the boot-time assignment of device resources, and to hotplug systems such as USB and Firewire.
Some devices, however, are not plug and play require that new device drivers be installed. To meet the size constraints of notebook and handheld computers, small credit card-sized expansion card have been developed. These card plug into USB, PCMCIA (called PC Card), or, most recently Express Slot.
BUS LINES
Known as bus-connects the parts of the CPU to each other.
Buses also link the CPU to various other components on the system board.
A bus is a PATHWAY for bits representing data and instructions.
The number of bits that can travel simultaneously down a bus is known as the BUS WIDTH.
A bus is similar to multilane highway that moves bits rather than cars from one location to another.
The number of traffic lanes determines the bus width.
A highway (bus line) with more traffic lanes (bus width) can move traffic (data and instructions) more efficiently.
Bus design or bus architecture is an important factor relating to the speed and power for a particular computer.
EXPANSION BUSES
Computer system has two basic categories of buses
1. System buses, connects the CPU to memory on the system board
2. Expansion buses, connects the CPU to other components on the system board, including expansion slots.
Computer systems typically have a combination of different types of expansion buses. The principal types are PCI, USB, Firewire, SATA, and PCIe.
PERIPHERAL COMPONENT INTERACONNECT (PCI) was originally developed to meet the video demand of graphical user interfaces.
UNIVERSAL SERIAL BUS (USB) it combines with a PCI bus on the system board to support several external devices without using expansion card or slot.
FIREWIRE BUSES are similar to USB buses. Although reports differ, fireWire buses are generally considered slightly faster than the USB 2.0 bus
SERIAL ADVANCES TECHNOLOGY ATTACHMENT (SATA) buses are one of the newest buses. It is much faster than USB 2.0 and FireWire buses and is now widely used to connect high-speed storage devices to the system board.
PCI EXPRESS (PCIe) is another recently developed bus. It is widely used in many of today's most powerful components
Ports
:: is a socket for external devices to connect to the system unit.
:: some ports connect directly to the system board while others connect to cards that are inserted into slots on the system board.
:: some ports are standard features of most computer systems and others are more specialized.
:: Standard Ports:
- for specific device-mouse, keyboard, video ports
- for different device-serial ports, parallel ports, Universal serial bus (USB) ports,FireWire ports, Ethernet ports.
Legacy Port
A legacy port is a computer port or connector that is considered fully or partially superseded
- Serial Ports
- are used for a wide variety of purposes.
- They are often used to connect a mouse, keyboard, modem and many other devices to system unit.
- send data one bit at a time and very good for sending information over a long distance
2. Parallel Ports
- used to connect external devices that need to send or receive a lot of data over a short distance.
- send 8 bits of data simultaneously across 8 mostly used to connect printers to the system unit.
3.Universal Serial Bus (USB) Ports
- have virtually replaced serial and parallel port
- faster and one USB can used to connect several devices to the system unit.
4. FireWire Ports
- have comparable speed to USB 2.0 ports and provide connections to specialized FireWire devices such as camcorders and storage devices.
5. Ethernet Ports
- are high speed networking port that has become a standard for many of today's computers.
allows you to connect multiple computers for sharing files or to a DSL or cable modem for high speed Internet access.
Specialized Ports
1. Sony/Philips Digital Interconnect Format (S/PDIF) or optical audio connections.
-used to intergrate computers into high-end audio and home theatre systems.
2. High Definition Multimedia Interface (HDMI)-provide high-definition video and audio, making it possible to use a computer as a video jukebox or an HD video recorder.
3. Musical instrument digital interface (MIDI)-special type of serial port for connecting musical instruments like an electronic keyboard to a sound card. The sound card converts the music into a series of digital instructions. These instructions can be processed immediately to reproduce the music or saved to a file for later processing.
4. Infrared Data Association (IrDA)-provide a wireless mechanism for transferring data between devices. Instead of cables, the IrDA ports from each device are directly aligned and onfrared light waves are used to transmit data. one of the most common applications is to transfer data from either a handheld or notebook to a desktop computer.
Cable
:: used to connect exterior devices to the system unit via the ports.
:: one end of the cables is attached to the device and the other end has a connection that is attached to a matching connector on the port
Power Supply
:: Computer require direct current (DC) to power their electronic components and to present data and instructions.
:: DC power can be provided indirectly by converting alternating current (AC) from standard wall outlets or directly from baterries.
:: Desktop Computer: used power supply unit located within the system unit.
: this unit plugs into a standard wall outlet, converts AC to
DC and provides the power to drive all of the system unit
components.
:: Notebook Computers: use AC adapters that are typically located outside the
system unit.
: AC adapters plug into a standard wall outlet, convert
AC and DC, provide power to drive the system unit
components and can recharge the batteries.
: can be operated either using an AC adapter plugged
into a wall outlet or using battery power.
: notebook battery typically provide sufficient power for four hours before they need to be recharged.
:: Handheld Computers: use AC adapters located outside the system unit
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