Understanding Basic parts of computer hardware

1. COMPUTER HARDWARE
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2. COMPUTER HARDWARE
Computer hardware is the collection of physical parts of a computer system. This
includes the computer case, monitor, keyboard, and mouse. It also includes all the
parts inside the computer case, such as the hard disk drive, motherboard, video
card, and many others. Computer hardware is what you can physically touch.
Definitions
A computer system consists of two major elements: hardware and software.
Computer hardware is the collection of all the parts you can physically touch.
Computer software, on the other hand, is not something you can touch. Software is
a set of instructions for a computer to perform specific operations. You need both
hardware and software for a computer system to work.
Some hardware components are easy to recognize, such as the computer case,
keyboard, and monitor. However, there are many different types of hardware
components.
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3. DIFFERENT COMPONENTS OF
COMPUTER
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4. POWER SUPPLY
What is a powersupply and what does it do?
The power supply unit (PSU) in a PC regulates and delivers the power to the
components in the case.
Standard power supplies turn the incoming 110V or 220V AC (Alternating
Current) into various DC (Direct Current) voltages suitable for powering the
computer's components.
Power supplies are quoted as having a certain power output specified in
Watts, a standard power supply would typically be able to deliver around 350
Watts.
The more components (hard drives, CD/DVD drives, tape drives, ventilation
fans, etc) you have in your PC the greater the power required from the power
supply.
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5. There are 3 types of power supply in common use:
1. AT PowerSupply - used in very old PCs.
2. ATXPowerSupply - still used in some PCs.
3. ATX-2 PowerSupply - commonly in use today.
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6. Original IBMPC, XT and AT standard
The first IBM PC power supply unit (PSU) supplied two main voltages: +5 V
and +12 V. It supplied two other voltages, −5 V and −12 V, but with limited
amounts of power. Most microchips of the time operated on 5 V power. Of the
63.5 W these PSUs could deliver, most of it was on this +5 V rail.
The +12 V supply was used primarily to operate motors such as in disk drives
and cooling fans. As more peripherals were added, more power was delivered
on the 12 V rail.
Original IBM power supplies for the PC (model 5150), XT and AT included a
line-voltage power switch that extended through the side of the computer
case.
These power supplies were generally not capable of power saving modes
such as standby or "soft off", or scheduled turn-on power controls.
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7. ATXstandard
When Intel developed the ATX standard power supply connector (published
in 1995), microchips operating on 3.3 V were becoming more popular,
beginning with the Intel 80486DX4 microprocessor in 1994, and the ATX
standard supplies three positive rails: +3.3 V, +5 V, and +12 V. Earlier
computers requiring 3.3 V typically derived that from a simple but
inefficient linear regulator connected to the +5 V rail.
The ATX connector provides multiple wires and power connections for the
3.3 V supply, because it is most sensitive to voltage drop in the supply
connections. Another ATX addition was the +5 V SB (standby) rail for
providing a small amount of standby power, even when the computer was
nominally "off".
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8. ATX12V standard
As transistors become smaller on chips, it becomes preferable to operate
them on lower supply voltages, and the lowest supply voltage is often desired
by the densest chip, the central processing unit. In order to supply large
amounts of low-voltage power to the Pentium and subsequent
microprocessors, a special power supply, the voltage regulator module began
to be included on motherboards. Newer processors require up to 100 A at 2 V
or less, which is impractical to deliver from off-board power supplies.
To reduce the power losses in the 5 V supply, with the introduction of
the Pentium 4 microprocessor, Intel changed the processor power supply to
operate on +12 V, and added the separate four-pin P4 connector to the new
ATX12V 1.0 standard to supply that power.
Modern high-powered graphics processing units do the same thing, resulting
in most of the power requirement of a modern personal computer being on
the +12 V rail.
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9. POWER RATINGThe overall power draw on a PSU is limited by the fact that all of the supply rails come
through one transformer and any of its primary side circuitry, like switching
components.
Total power requirements for a personal computer may range from 250 W to more
than 1000 W for a high-performance computer with multiple graphics cards.
Personal computers without especially high performing CPUs or graphics cards
usually require 300 to 500 W. Power supplies are designed around 40% greater than
the calculated syste m po we r co nsum ptio n. This protects against system performance
degradation, and against power supply overloading.
Power supplies label their total power output, and label how this is determined by
the electrical current limits for each of the voltages supplied. Some power supplies
have no-overload protection.
The system power consumption is a sum of the power ratings for all of the
components of the computer system that draw on the power supply. Some graphics
cards (especially multiple cards) and large groups of hard drives can place very heavy
demands on the 12v lines of the PSU, and for these loads, the PSU's 12 V rating is
crucial.
The total 12 V rating on the power supply must be higher than the current required by
such devices so that the PSU can fully serve the system when its other 12 V system
components are taken into account.
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10. INTRODUCTION TO SMPS (SWITCHED
MODE POWER SUPPLY)
Switching Mode Power Supply(SMPS) uses a switching regulator to convert
electric power efficiently. SMPS transfers electric power from a source ( AC
mains) to the load by converting the characteristics of current and voltage.
SMPS always provide a well regulated power to the load irrespective of the
input variations. SMPS incorporates a Pass transistor that switches very fast
typically at 50Hz and 1 MHz between the on and off states to minimize the
energy waste. SMPS regulates the output power by varying the on to off time
using minimum voltage so that efficiency is very high compared to the linear
power supply.
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11. The SMPS essentially has
1. Input rectifier
2. Inverter
3. Voltage converter
4. Output regulator
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12. Input rectifier
The AC input from mains is first rectified in the SMPS using a rectifier to
convert it into DC. The rectifier consisting of a full wave diode
bridge or module that produces an unregulated DC voltage to the Smoothing
capacitor. The input AC passing into the rectifier has AC voltage pulses that
may reduce the power factor. So control techniques are used to force the
average input current to follow the sine wave.
Inverter
This stage converts the rectified DC into AC using a poweroscillator. The
power oscillator has a small output transformer with a few windings at the
frequency 20-100 kHz. Switching is controlled by a MOSFET amplifier. The
output AC voltage is usually isolated optically from the input AC by using
an OptocouplerIC for safety reasons.
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13. Voltage converter
This stage has a high frequency transformer and the inverted AC drives its
primary windings. This creates the up and down voltage at the output. If DC is
required, the output AC is converted to DC using a rectifier circuit using
Silicon diodes or Schottky diodes (fast recovery and minimum loss of current and
low forward voltage drop) .
Output regulator
The output stage always monitors the output voltage by comparing with
a reference voltage using a feedback system. For safety reasons, the output stage
is isolated by an optoisolator as seen in the SMPS of computers.
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14. Added advantages of SMPS overthe conventional linearpowerregulators
are:
1. Light weight since the transformer is too small and it it operates at high
frequency of 50Hz-1MHz.
2. Output voltage is well regulated and controlled by duty cycle and there is
little resistive loss since the transistor fully on or off during switching.
3. Greater efficiency since the switching transistor dissipates very little heat.
Disadvantages:
The SMPS can fail and can cause very high output voltage that destroys the
equipment.
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17. UNINTERRUPTIBLE POWER SUPPLY
(UPS)
The full form of the UPS is an uninterruptible power source or uninterruptible
power supply. It is an electrical device, gives emergency power to various
loads when the input power typically fails.
The run time of battery for most UPS is relatively short but enough to start a
standby power source. The main purpose of a UPS is to provide a protection
to the equipments like computers, electrical equipment, computer and data
centers when there is a power disruption.
This device keeps a computer running for a few minutes after a power
disruption and protects the data in the computer.
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18. Types of UPS
Uninterruptible Power Supply devices are classified into different types such
as
1.The Standby UPS
2.Standby-Ferro UPS
3.The Line Interactive UPS
4.Double Conversion
5.Delta Conversion UPS
6.Online UPS
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19. The Standby UPS
The Standby UPS is the most common type used for Personal Computers.
Standby UPS, also known as off-line or line-preferred UPS, typically consists
of an AC/DC and DC/AC inverter, a battery, a static switch, a low pass filter
to reduce switching frequency from the output voltage. The standby system
operates with the switch setting the AC input as a primary power source, and
alternating to the battery and inverter as backup sources in case of primary
power failure.
The inverter normally remains on standby, only activating when the power
fails and the transfer switch automatically switches the electrical load to the
backup units. This type of UPS system provides a high degree of efficiency,
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20. Standby-Ferro UPS
The Standby-Ferro UPS was once the dominant form of UPS in the 3-15kVA
range. This design depends on a special saturating transformer that has
three windings (power connections). The primary power path is from AC
input, through a transfer switch, through the transformer, and to the output.
In the case of a power failure, the transfer switch is opened, and the inverter
picks up the output load. In the Standby-Ferro design, the inverter is in the
standby mode, and is energized when the input power fails and the transfer
switch is opened. The transformer has a special "Ferro-resonant" capability,
which provides limited voltage regulation and output waveform "shaping".
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21. Line Interactive UPS
The Line Interactive UPS is the most common design used for small
business, Web, and departmental servers. In this design, the battery-to-AC
power converter (inverter) is always connected to the output of the UPS.
Operating the inverter in reverse during times when the input AC power is
normal provides battery charging.
In case of power failure, the transfer switch can shift electrical flow from the
battery to the system output. Because the inverter is continuously connected
to the output, the UPS provides additional filtering and lowers the risk of
switching transients.
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22. Double Conversion
Double conversion UPS systems are commonly used for higher voltage
applications and they feature a configuration similar to those of standby
units, but with a primary power path focused on the inverter rather than the
AC main. This type of UPS system takes virtually no time to transfer between
modes because input AC power failure does not trigger the transfer switch.
Instead, the input AC charges the backup battery, which in turn powers the
output inverter.
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23. Delta Conversion UPS
Delta Conversion is a relatively recent addition to the uninterruptible power
supply industry and was introduced to alleviate some of the disadvantages
presented by double conversion systems. Like the double conversion design,
the delta conversion UPS has an inverter continuously supplying load
voltage, however, it also issues power to the inverter output. Under power
failure or electrical distortions, this UPS acts similarly to a double conversion
unit, but provides more efficient energy performance by converting power
from input to output rather than cycling between power and battery sources.
It is more compatible with generator systems and produces less heating and
component wear.
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24. Online UPS
The online UPS is also called as double conversion online uninterruptible
power supply. This is the most commonly used UPS. The designing of this
UPS is similar to the Standby UPS, excluding that the primary power source
is the inverter instead of the AC main. In this UPS design, damage of the i/p
AC does not cause triggering of the transfer switch, because the i/p AC is
charging the backup battery source which delivers power to the o/p inverter.
So, during failure of an i/p AC power, this UPS operation result in no transfer
time.
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25. PROCESSORS AND ITS TYPES
Processor decides the speed of the computer that it will execute the
instruction fast or it will process slow.
The pro ce sso r is the heart of the computer. It is an integral part of
the computer that controls all the working of the computer.
Pro ce sso rs lie at the he art o f allm o de rn co m pute rs , not only personal
computers, and are also EMBEDDED as controllers in many industrial and
domestic appliances, from cars to washing machines. A single
microprocessor chip, together with some memory chips, forms the basis for a
simple computer (and for some embedded applications may even have the
memory integrated onto the same chip).
The Pro ce sso r is a silico n chip asse m ble d o n the m o the rbo ard fo r pe rfo rm ing
calculatio n, execution instructions and controlling all peripheral devices.
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26. Before moving ahead some terms related to microprocessors like GHz,
Systemclock, 32 bit or 64-bitoperating system. Why do we use all these
terms for system specification?
All these terms used to tell about the system’s instruction execution speed,
its data capability how much bits data it can handle? For example Intel i3
CPU @ 2.40 GHz with 32 bit operating System. Means that 1 GHz
means=1000000000= 1 billion. Microprocessors have 2.4 billion clock-pulses
in one second. In each clock,pulse CPU has the opportunity to execute the
instruction. But it is not necessary that each instruction getsexecuted in one
clock pulse. It may require different -different clock pulse for execution.
32 bit or 64-bit operating system can handle 32 or 64-bit data during
execution of one instruction. Basically, it shows the capacity of CPU to
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27. Types of MicroprocessororProcessor
We have basically two categories of microprocessors listed below with
a small description.
CISC (Complex Instruction set computing):A complex instruction set
computer is a computer where single instructions can perform numerous low-
level operations like a load from memory, an arithmetic operation, and a
memory store or are accomplished by multi-step processes or addressing
modes in single instructions, as its name proposes “Complex Instruction Set ”.
RISC (Reduced Instruction set computing): A reduced instruction set
computer is a computer which only uses simple commands that can be
divided into several instructions which achieve low-level operation within a
single CLK cycle, as its name proposes “Reduced Instruction Set”.
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28. CISC: It was developed by Intel. CISC is a type of design for the computers.
CISC based computer will have shorter programs which are made up of
symbolic machine language.
A Complex Instruction Set Computer(CISC) supplies a large number of
complex instructions at the assembly language level. During the early years,
memory was slow and expensive and the programming was done in
assembly language. Since memory was slow and instructions could by
retrieved up to 10 times faster from a local ROM than from main memory,
programmers tried to put as many instructions as possible in a microcode.
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29. RISC: RISC is a type of microprocessor that has a relatively limited number
of instructions. It is designed to perform a smaller number of types of
computer instructions so that it can operate at a higher speed (perform more
million instructions per second, or millions of instructions per second). Earlier,
computers used only 20% of the instructions. Making the other 80%
unnecessary. One advantage of reduced instruction set computers is that
they can execute their instructions very fast because the instructions are so
simple.
RISC chips require fewer transistors, which makes them cheaper to design
and produce. In a RISC machine, the instruction set contains simple, basic
instructions, from which more complex instructions can be composed. Each
instruction is of the same length, so that it may be fetched in a single
operation. Most instructions complete in one machine cycle, which allows the
processor to handle several instructions at the same time.
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30. Advantages :
i) Speed : Since a simplified instruction set allows for a pipelined, superscalar
design RISC processors often achieve 2 to 4 times the performance of CISC
processor using comparable semiconductor technology and the same clock
rates.
ii) SimplerHardware : Because the instruction set of a RISC processor is so
simple, it uses up much less chip space; extra functions, such as memory
management units or floating point arithmetic units, can also be placed on the
same chip. Smaller chips allow a semiconductor manufacturer to place more
parts on a single silicon wafer, which can lower the per-chip cost dramatically.
iii) ShorterDesign Cycle : Since RISC processors are simpler than
corresponding CISC processors, they can be designed more quickly, and can
take advantage of other technological developments sooner than
corresponding CISC designs, leading to greater leaps in performance
between generations.
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31. Starting with Intel Processors: Intel founded by Gordon Moore and Robert
Noyce on July 18, 1968. The company bought the rights to use the name
“Intel”, short name for integrated electronics.
4-bit processor: They invented a microprocessor chip Intel 4004, having
transistors 2300, clock rate 740 KHz, Memory up to 4096 bytes.
8-bit processor: Intel 8080(1974) microprocessor is broken through for the
computer industry. It was 10 times faster than Intel 8008(1972).
Transistors=4500
Clock rate =2 MHz
Feature size =6 Microns.
Intel 16 bit processor: Processors are 8086, 8088, 80186, 80286.
Intel 80286(1989) microprocessor contain
Transistors=1, 34,000
Clock rate =6 to 25 MHz
Memory=up to 16 MB
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32. Intel 32 bit processor: First time the concept of Cache was introduced in Intel
80486.
Transistors=11, 80,235, Clock rate =16 to 100 MHz, Memory=up to 4 GB,
Feature size =1 Microns, Cache size=8to 16 kb
With the passage of time, Intel modified its technology and invented Intel
Pentium, Intel Pentium Pro, Intel Core processor, Intel i3, Intel i5 and Intel i7.
More processors working on different platforms are:
Clovertown and Woodcrest are 64-bit processor->used for Server &
workstation. They used 65 nm technologies.
Conroe (65-Technolgy): Used for Desktop Computing.
Merom (65-Technolgy): Used for mobile computing. It introduced on July 27,
2006.
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35. MOTHERBOARD
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36. A motherboard is the physical arrangement in a computer that contains the
computer's basic circuitry and components. The most common motherboard
design in desktop computers today is the AT, based on the IBM AT
motherboard. A more recent motherboard specification, ATX(ATX(Advanced
Technology eXtended), improves on the AT design.
In both the AT and ATX designs, the computer components included in the
motherboard are:
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37. The microprocessor
(Optionally) coprocessors
Memory
basic input/output system (BIOS)
Expansion slot
Interconnecting circuitry
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38. COMPONENTS OF A COMPUTER MOTHERBOARD
The following are the main components found on a computer motherboard:
Memory and theirSlots: The computer memory (RAM) is one of the most
important parts of the system board. The number of memory chips of a
motherboard depends on the type of computer and its capacity. There slots
are usually white and black and very close to each other.
Expansion cards: Expansion cards are a typical component of
nonintegrated system board as indicated earlier in this discourse. An
example is a graphic card. However this can be integrated into the
motherboard it depends on the type of circuitry.
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39. CPU and slots: The central processing unit and the sockets is highly prolific
part of the computer. It is located right on the motherboard. And it is easily
identifiable as a result of the heat sink or cooling fan directly on it.
BIOS Chip: Just like the CPU, the BIOS chip occupies a top position in terms
of the order of importance on the system board. It directs the CPU with
respect to how it relates with other parts of the computer. The Basic Input
and Out System chip or integrated circuit is fixed on board and it is also
easily identifiable. BIOS and the name of the manufacturer are usually
written on the chip.
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40. CMOS Battery: The complementary Metal Oxide Semiconductor (CMOS) is
a small battery on the system board that powers the CMOS memory. The
CMOS memory keep very important settings in the computer such as date,
time, configuration of the hard drive etc. in such a way that when the
computer is switched off such settings are maintained.
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41. •Floppy and Hard DiskConnectors: The Hard drive is the mass storage
device of the computer system, same with the floppy disk. They are onboard
connecting interfaces that enable the computer communicate with both
drives.
•Expansion slots: Expansion slots on the motherboard or a riser board make
it possible for an additional card or board to be connected to the main board.
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42. Jumpers and DIPswitches(Dual In-Line Package): Jumpers and DIP
switches used to configure the system board serving as a regulator for the
amount of voltage supply as required by the various components on the
motherboard especially the processor. This is automatic in some recent
motherboards.
These are the main components of a computer motherboard. There are
other peripherals which represents basic electronics components such as
capacitors, resistors, regulators etc. All these work together to make up a
complete and working circuitry.
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43. WHAT IS BUS
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In a computer or on a network, a bus is a transmission path on which signals
are dropped off or picked up at every device attached to the line. Only
devices addressed by the signals pay attention to them, the others discard
the signals. According to Winn L. Rosch, the term derives from its similarity
to auto buses that stop at every town or block to drop off or take on riders

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In general, the term is used in two somewhat different contexts:
(1) A bus is a network topology or circuit arrangement in which all devices
are attached to a line directly and all signals pass through each of the
devices. Each device has a unique identity and can recognize those signals
intended for it.
(2) In a computer, a bus is the data path on the computer's motherboard that
interconnects the microprocessor with attachments to the motherboard in
expansion slots (such as hard disk drives, CD-ROM drives, and graphics
adapters).

45. WHAT IS SYSTEM BUS?
A systembus is a single computer bus that connects the major components
of a computer system. It combines the functions of a data bus to carry
information, an address bus to determine where it should be sent, and a
control bus to determine its operation.
The direction of signal flow for the different buses is indicated on figures in
the computer’s technical manuals. The direction may be unidirectional or
bidirectional depending on the type of bus and type of computer.
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46. TYPES OF BUSES
All computers use three types of basic buses. The name of the bus is
generally determined by the type of signal it is carrying or the method of
operation.They are as follows:
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47. 1. Control (also called timing and control bus), address, and data (also
called a memory bus) buses
2. Instruction (I), Operand (O), Input/Output Memory (I/O MEM) or
Input/Output Controller (IOC), and Computer Interconnection System
(CIS)
3. Time multiplexed bus
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48. CONTROL BUS
The control bus is used by the CPU to direct and monitor the actions of the
other functional areas of the computer. It is used to transmit a variety of
individual signals (read, write, interrupt, acknowledge, and soforth)
necessary to control and coordinate the operations of the computer.
The individual signals transmitted over the control bus and their functions are
covered in the appropriate functional area description.
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49. ADDRESS BUS
The address bus consists of all the signals necessary to define any of the
possible memory address locations within the computer, or for modular
memories any of the possible memory address locations within a module.
An address is defined as a label, symbol, or other set of characters used to
designate a location or register where information is stored. Before data or
instructions can be written into or read from memory by the CPU or I/O
sections, an address must be transmitted to memory over the address bus.
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50. DATA BUS
The bidirectional data bus, sometimes called the memory bus, handles the
transfer of all data and instructions between functional areas of the
computer.
The bidirectional data bus can only transmit in one direction at a time.
The data bus is used to transfer instructions from memory to the CPU for
execution. It carries data (operands) to and from the CPU and memory as
required by instruction translation. The data bus is also used to transfer
data between memory and the I/O section during input/output operations.
The information on the data bus is either written into
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52. WHAT IS SYSTEM CHIPSET
In a computer system, a chipset is a set of electronic components in an
integrated circuit that manages the data flow between the processor,
memory and peripherals. It is usually found on the motherboard. Chipsets
are usually designed to work with a specific family of microprocessors.
Because it controls communications between the processor and external
devices, the chipset plays a crucial role in determining system performance.
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53. A number of integrated circuits designed to perform one or more related
functions. For example, one chipset may provide the basic functions of a
modem while another provides the CPU functions for a computer. Newer
chipsets generally include functions provided by two or more older chipsets.
In some cases, older chipsets that required two or more physical chips can
be replaced with a chipset on one chip.
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54. NORTH AND SOUTH BRIDGE?
The chipset normally consists of two major microchips. These are known as
the North bridge and the South Bridge.
The North Bridge Handles data for the graphics port whether that be
AGP(Accelerated Graphics Port) or PCI(Peripheral component Interconnect)
express and the main memory which includes the FSB (Front side bus).
Although both chips are required for the PC to work the North Bridge handles
most of the very important tasks such as the connection between the CPU
and main memory bank.
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55. The South Bridge handles data from the PCI x1 slots and can also have
integrated components such as Audio and/or onboard graphics.
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56. WHAT IS SYSTEM BIOS
BIOS (basic input/output system) is the program a personal computer's
microprocessor uses to get the computer system started after you turn it on.
It also manages data flow between the computer's operating system and
attached devices such as the hard disk , video adapter , keyboard , mouse ,
and printer .
BIOS is an integral part of your computer and comes with it when you bring it
home. (In contrast, the operating system can either be pre-installed by the
manufacturer or vendor or installed by the user.) BIOS is a program that is
made accessible to the microprocessor on an erasable programmable read-
only memory (EPROM) chip.
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57. When you turn on your computer, the microprocessor passes control to the
BIOS program, which is always located at the same place on EPROM.
When BIOS boots up (starts up) your computer, it first determines whether
all of the attachments are in place and operational and then it loads the
operating system (or key parts of it) into your computer's random access
memory (RAM) from your hard disk or diskette drive.
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