4.Computer Hardware -Components
Topics:
• Processor
• RAM
• Motherboard
• Hard Disk
• Cards
• Ports
• BIOS
• Peripherals
• Cabinet
Processor
• Processor is the brain of your computer.
• Some key concepts
– Clock : In a computer, clock speed refers to the number of pulses
per second that sets the tempo for the processor.
– Cache
A small but fast memory area.
Levels of cache exists.
– Bus (FSB and BSB) : Collection of wires connecting different
devices.
– Pipeline : Implementation technique where multiple instructionsare ovelapped.
• 32/64 bit processors
– The amount of data a processor can process in a clock cycle.
• Clock speed and overclocking
– BUS SPEED x MULTIPLIER = CPU SPEED (Clock)
• Which processor is faster?
– 100MHz x 10.0 = 1000 MHz
– 133MHz x 7.5 = 997.5 M
Some commercially available processors
• Pentium I-IV
• Celeron
• Athlon
• Duron
• Cyrix C3
• Itanium (64 bit)• Opteron (64 bit)
RAM
What is RAM?
– Random Access Memory.
– RAM is volatile.
• Broadly classified as
– Static RAM.
– Dynamic RAM.
• Static RAM
– Fast, has lower access time.
– Typical access times 5-25 ns.
– Expensive.
– Cache memory is Static RAM.
• Dynamic RAM
– Slower, has higher access time than Static RAM.
– Typical access times 60-120 ns.
– Much cheaper than SRAM.
– Main Memory is Dynamic RAM.
• Memory Bandwidth is proportional to System Bus speed.
• Dynamic RAM are further classified as
– EDORAM (Extended DataOut DRAM).
– SDRAM (Synchronous DRAM) : PC100, PC133.
– DDR SDRAM (Double Data Rate SDRAM)
- Allows activationof the output operation to occur on both rising and falling clockedge and hence doubles the speed of operation.
– RDRAM (Rambus DRAM)
- Developed by Rambus and Intel,can support very high bus speeds.
• Memory Slots/Sockets on Motherboard
– SIMM (Single In-Line Memory Module) Smaller in length and capacity than DIMM.
– DIMM (Dual In-Line Memory Module) Larger in length and capacity than SIMM.
– SIMM and DIMM are just packaging types only and do not affectthe performance.
Motherboard
• The main circuit board which connects all the device on a microcomputer;Also called main board or system board.
• Chipset
– The chipset controls the system and its capabilities. It is the hubof all data transfer.
– Chipsets are integrated, and are not upgradable without buyinga whole new motherboard.
– Some of the items it dictates Memory controller Real-time clock Keyboard and mouse controller Secondary cache controller PCI bridge EIDE controller
• Motherboards are designed for specific Processors. A single motherboardcannot be used with different types of Processors.
• The different system bus speeds supported by the Motherboardshould be of prime consideration.• Form Factors
– The form factor is the physical size and dimensions of the motherboard.The form factor determines the general layout, size,and feature placement on a motherboard. Baby AT ATX Proprietary
• Onboard devices
- Video/Audio/LAN
– Lower cost.
– Lesser Flexibility.
• Upgradability
– Bus speeds supported.
– Number of expansion slots.
– Number and Types of IO ports available.
Hard Disk
What is HardDisk?
– Stores data in magneticdisk like medium
• Non-volatile mass storage device.• Has very high access timeas compared to RAM (10-20million ns).
• Very cheap as compared toRAM and so large in capacity.
• Interface standards
– IDE (Integrated Drive Electronics)
The hard disk drive includes the drive controller circuitry and
hence known as IDE.
It can support atmost 4 devices.
16 bit interface standard; 40 pin/80 pin connector.
ATA-33/66
– SCSI (Small Computer System Interface)
General pupose interface standard used for connecting manytypes of devices to the PC.
Supports 7 to 15 different devices like hard disk, scanner, CDROM etc.
32 bit interface standard and more expensive than IDE.
Allows simultanous access for faster data transfer.
• Connecting Multiple IDE Harddisks/CD-Roms– Primary/Secondary and Master/Slave settings– Jumper settings
• Performance parameters– Rotation speed.– Average seek time.
How does the hard disk store data?
On each of the platters there is a thin layer of magnetic film. Data storage on hard disks is very similar to that of a cassette tape. Data is stored in many 1's and 0's stored in different directions on the magnetic film by using a very fine oxide. These binary digits are arranged in different ways to represent different characters. When these are read back by the head the data is retrieved and processed. because no physical contact with the platters is made the disk can be re-written time and time again without damage to the disk or its platters.
File Systems
A file system is the way in which your computer stores data on the hard disk. The most common file systems are FAT16 for older computers, FAT32 and NTFS. FAT stands for File Allocation Table. NTFS stands for NT FileSystem. Both have advantages and disadvantages. FAT16 was a very limited file system in the way that it would store data very in-efficiently, every file would take up a minimum of 32Kb in space as this was the minimum cluster size in a FAT16 system. Also it was only capable of using hard disks up to 2Gb in size. FAT32 solved this problem by reducing the cluster size to 4kb which saved a lot of wasted space and also allowed disk sizes up to 2 Terra bytes. NTFS is believed to be a far greater file systems than any of the FAT's. The cluster sizes can be altered to anything as low as 512bytes which means almost no wasted space on the hard disk. The maximum disk size is a unbelievable 256 Terra bytes, which is very big !!!. NTFS also has added security for file loss.
Measuring the Speed of a Hard Disk
There are various ways of measuring the speed of the hard disk. The main ones are the maximum data transfer rate, the spindle rotation speed and the seek time.
Maximum Transfer Rate - This is the highest amount of data that can be transferred per second. Common forms of hard disks come with an ATA format. the speed rating of an ATA100 disk would be 100Mb/s. Likewise a ATA66 disk would be able to transfer a maximum of 66Mb/s. Past the older ATA standard just mentioned comes the newer S-ATA standard (serial- ATA). S-ATA 1.0 transfers at a max rate of 1.5Gb/s S-ATA 2.0 transfers at a max rate of 3Gb/s and S-ATA 3.0 can tranfer data a maximum rate of 6Gb/s
Spindle Rotation Speed - The rotation speed of the disk really is the basis of the other two factors of hard disk speed. The faster the rotation speed, the more data can be written per second and the quicker it is to find the correct data on the platter. A Common speed is 7200RPM (revolutions per minute)
Seek Time - The seek time of a hard disk is the average time it takes for the disk to find the data you need on the platters. A fast spinning, highly accurate and responsive disk will have a shorter seek time and will perform much better, especially when the data is scattered around the disk. Seek time is measured in milliseconds or ms.
Video Card
What’s a Graphics Card?
– A modern graphics card is a circuit board with memory and adedicated processor.
– Converts digital information into the pixels to display it on themonitor.
• Frame Buffers
– The card simply holds a frame of information that is sent to thescreen.
– Pixel updates are done by the microprocessor.
– Slow.
• Graphics accelerators with GPU
– Pixel updates are done by the GPU.
– GPU is optimised for graphics operations.
– Reduces load on the main processor.
Bus Interfaces PCI
• Peripheral Components InterconnectBus Interfaces AGP
Bus Interfaces AGP
• Accelerated Graphics Port
On board Graphics Accelerator
• On board graphics accelerators share system memory.
• Wide range of cards
– 3D Accelration.
– Video Memory.
• Modern day Graphics cardsare more powerful than Pentiumprocessor!
• Expensive component of yourComputer.
• Choosing a Graphic card
– PCI or AGP.
– Integrated or Add-on card.
– Non-Accelrated or 3D accelrated.
– Cost.Sound Card
• Converts digital data (bits) into analog sound wave and vice-versa.
• Has Digital Signal Processor, RAM, ADC and DAC.
• Has jacks for speaker, microphone, line in, line out and joysticks.
• Choosing a soundcard
– Integrated or External add-on card.
– CPU Utilization.
– Sound reproduction capabilities (dolby, 5.1 channels etc.).
– Cost.
Network Interface Card
• Connects PC to LAN (LocalArea Network).
• Ethernet, Token Ring.
• Speeds
– 10Mbps
– 100Mbps
• Onboard or Add-on Card?
– 3D Accelration.
– Video Memory.
• Modern day Graphics cardsare more powerful than Pentiumprocessor!
• Expensive component of yourComputer.
• Choosing a Graphic card
– PCI or AGP.
– Integrated or Add-on card.
– Non-Accelrated or 3D accelrated.
– Cost.Sound Card
• Converts digital data (bits) into analog sound wave and vice-versa.
• Has Digital Signal Processor, RAM, ADC and DAC.
• Has jacks for speaker, microphone, line in, line out and joysticks.
• Choosing a soundcard
– Integrated or External add-on card.
– CPU Utilization.
– Sound reproduction capabilities (dolby, 5.1 channels etc.).
– Cost.
Network Interface Card
• Connects PC to LAN (LocalArea Network).
• Ethernet, Token Ring.
• Speeds
– 10Mbps
– 100Mbps
• Onboard or Add-on Card?
Ports
• Serial
– Serial port “serializes” data.
– Mouse, Modems etc use Serial port.
• Parallel
– Bits transmitted in parallel.
– Used primaraly for Printers.
• PS/2– Used to interface keyboards andpointing devices.
– Frees the serial port for other devices.
• USB
– Data transfer rate 12Mbps/480Mbps.
– Multiple devices supported on the bus(127).
– Hot pluggable, Plug-and-play.
– Provide power through the cable.
– Host based• Firewire (IEEE 1394)
– Originally created by Apple and standardized in 1995.
– Fast transfer of data (up to 400 Mbps/800Mbps).
– Multiple devices supported on the bus (63).
– Hot pluggable, Plug-and-play.
– Provide power through the cable.
– Peer to peer.
– Supports synchronous devices.
BIOS
What is it?
- Basic Input Output System
Why is it necessary?
– boot up
• Important Functions
– Check CMOS Set-up.
– POST- Power On Self Test.
– Display system setting.
– Initiate bootstrap sequence.
Configuring BIOS
• System Time/Date.
• Boot Sequence.
• Plug and Play.
• Drive Configuration.
• Security.
• Power Management
Keyboard
• Switching action.
• No. of keys.
• Control, Functional, Special, Alpha-Numeric Keys.
• Connects to PC using PS/2 connector.
Function Keys for Windows
* F1 – Opens Help for the currently displayed program (this does not work on all programs).
* Windows Logo key and F1 – Opens Windows' Help.
* F2 – Highlights the name of a selected object for renaming in Windows Explorer, desktop, and some other Windows' programs. First, you need to select an item that can be renamed (like, a file or shortcut). After pressing F2, you can then type what you want to rename the object to.
* F3 – Brings up Search in Windows Explorer.
* F4 – Drops down the Address bar in Internet Explorer showing your previous locations. This allows you to scroll down and select one.
* Alt and F4 – Closes the currently displayed program.
* F5 – Refreshes the view in Windows Explorer, Internet Explorer (in other words, it looks at the source again and reloads the contents), and other programs. In MailWasher it checks the mail (which I guess would be a kind of refresh).
* F6 – moves the cursor around the structure of a program. Pressing it may cycle you from window to window or from place to place within the program. In Windows Explorer it moves you from the left pane to the right pane and back. This is similar to what the Tab key does.
* Alt and F6 – Switches between multiple windows in the same program (for example, when theNotepad Find dialog box is displayed, ALT+F6 switches between the Find dialog box and the main Notepad window).
* F7 – does not have any functionality in Windows. It may be used in individual programs.
* F8 – accesses Safe Mode if pressed at the right time while the computer is starting. Safe Mode is a trouble-shooting mode, which will start the computer with minimal drivers.
* F9 – does not have any functionality in Windows. It may be used in individual programs.
* F10 – Changes the focus to and from the menu. Pressing the Alt key will also do this. Once the focus is on the menu items, you can use the arrow keys to navigate to an item and the Enter key to select it.
* Shift and F10 – brings up the popup menu in Windows Explorer much like right clicking on an item does.
* F11 – Switches between regular screen mode and full screen mode. Full screen mode is like a maximized screen but with more screen space and less toolbar controls
* F12 – does not have any functionality in Windows. It may be used in individual programs.
You may have noticed that some of the Function keys are not used (F7, F9, F12) in Windows. That doesn't mean that they can't be used. You can assign them or any other key combination to quickly run programs that you frequently use. Here are instructions for doing that.
- Locate the shortcut of that program. The Start menu is a good place to find shortcuts (every icon in the Start menu is a shortcut). If the program doesn't have a shortcut, create one.
- Right click on the shortcut and select the Properties item from the popup menu.
- The Properties dialog will open. Go to the Shortcut tab.
- Put the curser in the Shortcut key textbox and press the Function key or key combination (like Alt + Ctrl + 2) which you want to use to start the program.
- The Function key name or key combination name will appear in the box.
- Click on the Apply button (or the OK button) and close the dialog.
To disable this, follow the above instructions but press Backspace or Delete in the Shortcut key textbox.
The Function keys are there to make your life easier. Now you can start using them.
Mouse
• Different shapes and size.
• 2 and 3 buttons mouse.
• Scroll mouse.
• Connects to PC using PS/2 connector.
• 2 and 3 buttons mouse.
• Scroll mouse.
• Connects to PC using PS/2 connector.
Monitor
• Cathode Ray Tube Monitor.
• Size - 15” to 21”.
• Resolution.
– CGA : 320 X 200 (4)
– EGA : 640 X 350 (16)
– VGA : 640 X 480 (256)
– SVGA : 1280 X 1024 (16.7 million)
• Display Quality - Refresh rate.
• Interlaced/Non-interlaced.
• Flat panel - LCD and Plasma.
• Size - 15” to 21”.
• Resolution.
– CGA : 320 X 200 (4)
– EGA : 640 X 350 (16)
– VGA : 640 X 480 (256)
– SVGA : 1280 X 1024 (16.7 million)
• Display Quality - Refresh rate.
• Interlaced/Non-interlaced.
• Flat panel - LCD and Plasma.
CD ROM/Writable
• Speed - 12x, 24x, 48x, 52x etc.
• Sturdier, Unaffected by magnetic fields.
• Sturdier, Unaffected by magnetic fields.
Printer
• Impact Printer - Dot matrix
– Selection : Speed, Unidirectional / Bidirectional.
– Adv. : Inexpensive, Multi-copy forms.
– Disadv. : Slow, Loud, Graphics of low Quality
• Non-impact Printer
– Inkjet– Thermal
– Laser– Adv. : Quiet, Can handle graphics, Varieties of fonts.
– Disadv. : Expensive.
– Selection : Speed, Unidirectional / Bidirectional.
– Adv. : Inexpensive, Multi-copy forms.
– Disadv. : Slow, Loud, Graphics of low Quality
• Non-impact Printer
– Inkjet– Thermal
– Laser– Adv. : Quiet, Can handle graphics, Varieties of fonts.
– Disadv. : Expensive.
Modem
• Speed - 56k, 33.6k, 28.8k
• Internal Modem
– Resides on the expansion board on theslot of the motherboard.
– Does not require separate poweradapter.
– Cheaper than external modem.– Has natural protection inside PC cabinet.
• External Modem– Resides on a self-contained box outsidethe PC.
– Requires external power adapter.
– Connected to PC’s serial port via thecable.
– Easy to install and troubleshoot suchas resetting the modem.
– Expensive than internal modems.
• Internal Modem
– Resides on the expansion board on theslot of the motherboard.
– Does not require separate poweradapter.
– Cheaper than external modem.– Has natural protection inside PC cabinet.
• External Modem– Resides on a self-contained box outsidethe PC.
– Requires external power adapter.
– Connected to PC’s serial port via thecable.
– Easy to install and troubleshoot suchas resetting the modem.
– Expensive than internal modems.
Cabinet
• Form Factor
• AT Cases
• ATX Cases
AT Cases
• Older Motherboards (pre-pentium)
• Advantages
- Well Established standard make.
– Easy and cheap design.
• Disadvantages
– Inefficient cooling.
– CPU socket location.
– Not suitable for P-II (& higher)
ATX Cases
• Newer Motherboards (Pentium based m/c)
• Advantages
– Efficient cooling.
– Easy accessibility for upgades.
– I/O are fixed onboard.
• AT Cases
• ATX Cases
AT Cases
• Older Motherboards (pre-pentium)
• Advantages
- Well Established standard make.
– Easy and cheap design.
• Disadvantages
– Inefficient cooling.
– CPU socket location.
– Not suitable for P-II (& higher)
ATX Cases
• Newer Motherboards (Pentium based m/c)
• Advantages
– Efficient cooling.
– Easy accessibility for upgades.
– I/O are fixed onboard.