week 2

The Computer Generations

In the beginning ....

 

 A generation refers to the state of improvement in the development of a product.  This term is also used in the different advancements of computer technology.  With each new generation, the circuitry has gotten smaller and more advanced than the previous generation before it.  As a result of the miniaturization, speed, power, and memory of computers has proportionally increased.  New discoveries are constantly being developed that affect the way we live, work and play.

Pre computers and Early Computers (before 1940s)

•      Experts concluded that ancient civilizations had the ability to count and compute.

•      Abacus – earliest recorded calculating device.

•      Others : slide ruler, mechanical calculator, Punch card tabulating machine (by Dr. Herman Hollerith, 1890s) and Sorter

•      Hollerith’s company eventually became IBM (International Business Machine)

The First Generation:   1940-1950 (The Vacuum Tube Years) 

 

The first generation computers were huge, slow, expensive, and often undependable. In 1946 two Americans, Presper Eckert, and John Mauchly built the ENIAC electronic computer which used vacuum tubes instead of the mechanical switches of the Mark I.  The ENIAC used thousands of vacuum tubes, which took up a lot of space and gave off a great deal of heat just like light bulbs do.  The ENIAC led to other vacuum tube type computers like the EDVAC (Electronic Discrete Variable Automatic Computer) and theUNIVAC I (UNIVersal Automatic Computer).

•      ENIAC [1945]: Designed by Mauchly & Echert, built by US army to calculate trajectories for ballistic shells during Worls War II. Around 18000 vacuum tubes and 1500 relays were used to build ENIAC, and it was programmed by manually setting switches

•      UNIVAC [1950]: the first commercial computer

•      John Von Neumann architecture: Goldstine and Von Neumann took the idea of ENIAC and developed concept of storing a program in the memory. Known as the Von Neumann's architecture and has been the basis for virtually every machine designed since then.

•      Features:

–     Electron emitting devices

–     Data and programs are stored in a single read-write memory

–     Memory contents are addressable by location, regardless of the content itself

–     Machine language/Assemble language

–     Sequential execution 

The Second Generation:  1950-1964 (The Transistor) 

In 1947  three  scientists ,  John Bardeen, William Shockley , and Walter Brattain working at AT&T's Bell Labs invented what would replace the vacuum tube forever.  This invention was the transistor which functions like a vacuum tube in that it can be used to relay and switch electronic signals.

•      First operating Systems: handled one program at a time
                                  

•      On-off switches controlled by electronically.
                                                

•      High level languages (COBOL and FORTRAN)
                           

•      Floating point arithmetic 

The Third Generation: 1964-1974 (Integrated Circuits)

 

The integrated circuit, or as it is sometimes referred to as semiconductor chip, packs a huge number of transistors onto a single wafer of silicon. Robert Noyce of Fairchild Corporation and Jack Kilby of Texas Instruments independently discovered the amazing attributes of integrated circuits.  Placing such large numbers of transistors on a single chip vastly increased the power of a single computer and lowered its cost considerably.

•      Microprocessor chips combines thousands of transistors, entire circuit on one computer chip.

•      Semiconductor memory

•      Multiple computer models with different performance characteristics

•      The size of computers has been reduced drastically 

The Fourth Generation:  1974-Today (The Microprocessor)

      

•      VLSI = Very Large-Scale Integration

•      ULSI = Ultra Large Scale Integration

•      Combines millions of transistors                      

•      Single-chip processor and the single-board computer emerged                  

•      Creation of the Personal Computer (PC)               

•      Use of data communications

•      Massively parallel machine

The Fifth Generation: (now and the future)

                    

•      Based on artificial intelligence - computers can think, reason and learn

•      Primary means of input – voice and touch

•      Different computers construct such as optical computers that utilizes nanotechnology, or as entire general-purpose computers

Computer Architecture

 

•      Processor à center for manipulation and control  
                     
•      Memory à storage for instructions and data for currently executing programs  
                  

•      I/O system à controller which communicate with "external" devices: secondary memory, display devices, networks  
                  

•      Data-path & control à collection of parallel wires, transmits data, instructions, or control signal 

Computer processing power

•      When comparing computers, the power of the computer is important. It is determined by the speed and capacity (size) of each part of the computer.

•      Speed is measured in hertz (Hz) i.e. cycles per second.

•      Capacity is measured in bytes (B) where

                        1 byte = 8 bits (binary digits) = 1 character.

Categories of computers

Categorize based on size, capability and price.

1.     Embedded computers

2.     Mobile devices/ computers

3.     Personal computers

4.     Midrange servers

5.     Mainframes

6.     Supercomputers

1.           Embedded computers

 

•      A miniature computer embedded into a specific product for a specific function.

 

2. Mobile computers 

•      Fits on our lap/ hand, contain built-in computing or Internet capabilities.

3. Personal computers

•      Fully functioning portable or desktop computers, designed for a single user at a time.

4. Midrange Servers

•      Physically likes small cabinet, hosting data and programs available to a small group of users.

5. Mainframe computers 

•      Consume large space and powerful computers used to host a large amount of data and programs available to a wide range of users.

7.   Supercomputers 

•    Extremely powerful computers used for complex computation and processing.

System Unit

•      The system unit is a case that contains electronic components (processor, memory, expansion cards etc) and most storage devices.

System Unit components

•      Processor

•      Memory module

•      Expansion cards

–     Sound card

–     Modem card

–     Video card

–     Network interface card

   •      Ports and Connectors

Motherboard

        

        A motherboard (sometimes alternatively known as the mainboard, system              board,  planar board or logic board, or colloquially, a mobo) is aprinted circuit board (PCB) found in all modern computers which holds many of the crucial components of the system, such as the central processing unit (CPU) and memory, and provides connectors for other peripherals.

           

          These chip packages are available in motherboard…

–     single edge contact (SEC) cartridge

–     dual inline package (DIP)

–     flip chip-PGA  (FC-PGA) package

–     pin grid array (PGA)

Processor

                    

•      The processor is the most important part of the computer. It processes the data and controls the computer.

 

•      Powerful computers used as servers often have more than one processor.

 

•      A set of connectors used for carrying signals between the different parts of a computer is known as a bus.

 

•      Data is transferred constantly between the processor and memory along the system bus.

•      Each part of memory has its own memory address and the processor determines where processed data is stored by sending an address signal along an address bus and data along a data bus.

•      Peripherals: other parts that are connected to the CPU such as input devices, output devices, storage devices and communications devices.

The Central Processing Unit

 

•      Converts data into information

•      Control center

•      Set of electronic circuitry that executes stored program instructions

•      Two parts

–     Control Unit (CU)

–     Arithmetic Logic Unit (ALU)

CPU Components

Control Unit -CU

•      Part of the hardware that is in-charge

•      Directs the computer system to execute stored program instructions

•      Communicates with other parts of the hardware

Arithmetic Logic Unit – ALU

•      Performs arithmetic operations : Addition, Subtraction, Multiplication, Division

•      Performs logical and relational/ comparison operations : AND, OR, NOT, =, > , <

The Architecture of CPU

    

Main Memory

•      There are two types of memory:

–      RAM (random access memory): it holds the program instructions and the data that is being used by the processor – it looses its contents when power is turned off

–      ROM (read only memory): it holds the program instructions and settings required to set up the computer - it does not loose its contents when power is turned off

       Volatility

•      Refers to Memory’s ability to retain its content when electrical power is cut off.

•      There are two types : VOLATILE and NONVOLATILE

•      Volatile memory loses any data as soon as the system is turned off; it requires constant power to remain viable. Most types of RAM fall into this category.

•      Nonvolatile memory does not lose its data when the system or device is turned off. Most types of ROM fall into this category. 

       Random Access Memory(RAM)

        •        RAM can be of two types: Dynamic RAM (DRAM). Static RAM (also called on board cache). 

 

    DRAM :

  •      The storage cell circuits in dynamic RAM chips contain a transistor that acts in much the same way as a mechanical on-off switch. It must be refreshed every 2 milliseconds. A dynamic RAM chip thus provides volatile storage i.e. the data stored are lost in the event of a power failure. 

 

    SRAM : 

  •      Also volatile storage devices, more complicated, cost much more and take up more space for a given storage capacity than do DRAM. Static RAM are faster than DRAM. 

    Read Only Memory(ROM)

                      

•      (ROM) chip is installed by the manufacturer inside the computer. 

•      Also called firm ware, it retains instructions in a permanently accessible nonvolatile form. When the power in the computer is turned off, the instructions stored in ROM are not lost.

•      In addition to ROM, there are also PROMs, EPROMs, and EEPROMs. 

•      PROM stands for programmable read only memory: It works similar to that of ROM. PROM chips are custom made for the user by the manufacturer. The user determines what data and instructions are to be recorded on them. The data on PROM is permanent and cannot be erased. 

•      Erasable programmable read only memory (EPROM), developed as an improvement over PROM. The data on the EPROM can be read with the help of a special device that uses ultra violet light. The data or instructions on the EPROM are erasable and new data can be entered in its place. EPROM functions exactly same as PROM.

•      Electronically erasable programmable read only memory (EEPROM) avoids the inconvenience of having to take chips out of the computer to change data and instructions. Changes can be made electrically under software control. These are used in point of sale terminals to records price related data for products. The prices recorded on them can be easily updated as needed.

    RAM versus ROM

 

     •         ROM (Read only memory):

 

     We can only read the data. Data can’t be written every time, to write the data we need PROM, EPROM, OR EEPROM. ROM is non volatile in nature. The data stored in ROM is permanent in nature. Size of the ROM has nothing to do with processing.

     •         RAM (Random access memory): 

 

     We can read and write data on the chip. RAM has volatile memory. It looses its contents when the power is switched off. Size of the RAM makes difference in the processing i.e., bigger the size of the RAM more is the speed of processing. The data can be read and written at anytime. 

Input

    •      Input is any data and instructions entered into the memory of a computer – can be in the form of programs, commands, and user responses

    The Keyboard

 

     •      A keyboard is an input device that contains keys users press to enter data and instructions into a computer

 

     •      An ergonomic keyboard has a design that reduces the chance of wrist and hand injuries

 

     •      Keyboards on mobile devices typically are smaller and/or have fewer keys

 

     •      Some phones have predictive text input, which saves time when entering text using the phone’s keypad

 

 

  

    Pointing Devices

     •      A pointing device is an input device that allows a user to control a pointer on the screen

 

     •      A pointer is a small symbol on the screen whose location and shape change as a user moves a pointing device

 

     •      Popular pointing devices include:

 

        –     Mouse – can be wired or wireless

        –       Trackball – like an upside down mechanical mouse

        –     Pointing stick – a ‘rubber’ on the keyboard

         –      Touchpad – a small surface sensitive to pressure and motion

        –     Touchscreen – a screen sensitive to pressure and motion

      Digital Cameras

•      A digital camera is a mobile device that allows users to take pictures and store them digitally

•      Types : Studio cameras, Field cameras, point-and-shoot camera

•      Factors affecting the quality of shot : resolution and no. of bits stored in each pixel.

         

       Voice Input

       •      Voice input is the process of entering input (speech, music, sound effect) by speaking into a microphone

       •      Voice recognition is the computer’s capability of distinguishing spoken words

     

       Video Input

      •      Video input is the process of capturing full-motion images and storing them on a        computer’s storage medium

 

      •      A Web cam is a type of digital video camera that enables a user to:

-         Capture video and still images,

-         send email messages with video attachments,

-         add live images to instant messages,

-         broadcast live images over the internet,

-         make video telephone calls.

      •      A video conference is a meeting between two or more geographically separated people

 

 

 

Scanners and Reading Devices:

Optical Scanners

•      Data is captured directly from a source document such as order forms, invoices, paychecks, photos, etc. 

•      Popular types of scanners :

1.     Flatbed

2.     Pen or Handheld

3.     Sheet-fed

4.     Drum

Optical Readers

•      Optical character recognition (OCR) involves reading characters from ordinary documents

•      Optical mark recognition (OMR) reads hand-drawn marks such as small circles or rectangles

•      An OMR device scans the documents and matches the patterns of light

Bar Code Readers

•      A bar code reader, also called a bar code scanner uses laser beams to read bar codes

•      RFID Readers (Radio Frequency Identification) uses radio waves to communicate with a tag placed to an object.

•      RFID is an alternative to barcode readers as it does not require direct contact or line-of-sight transmission.

Magnetic Stripe card readers

•      Magnetic stripe card readers also called magstripe readers, read the magnetic stripe on the back of credit cards, bank cards, entertainment cards etc.

•      The magnetic strip contains information identifying the card issuer and the owner.

MICR

•      MICR (magnetic ink character recognition) devices read text printed with magnetized ink such on a cheque.

Output

•      Output is data that has been processed into a useful form.

•      An output device is any type of hardware component that conveys information to one or more people

Printers

                        

•      A printer produces text and graphics on a physical medium – usually papers.

•      Printed information is called a hard copy, or printout.

•      Two basic types:

o Impact

o Non-impact

•      The sharpness and clarity of printout (or print resolution) is measured in dpi (dots per inch).

Impact printer:

•      Characters/graphics are formed on the paper by physical striking contact between ink ribbon and paper

•      Examples are

            1. dot-matrix printer (continuous paper),

            2. line printer (mainframe/minicomputer)

Non-impact printer:

•      Forms characters and graphics without striking paper

•      Example:

                        1. Ink-jet printers

                        2. photo printers

                              3. Laser printers

Types of storage

1.     Hard disks

2.     Flash Memory storage

3.     Optical discs

4.     Other types :

1.     Tape

2.     Magnetic stripe cards & smart cards

3.     Microfilm & microfiche

             4.     Enterprise storage

        Storage

    v  Storage holds data, instructions, and information for future use.

    v  A storage medium is the physical material on which a computer keeps   

                    data, instructions, and information.

        Hard Disks

          •      A hard disk contains one or more inflexible, circular platters that use magnetic  

             particles to store data, instructions, and information

          •      A head crash occurs when a read/write head touches the surface of a platter

          •      Always keep a backup of your hard disk

          •      RAID (redundant array of independent disks) is a group of two or more 

              integrated hard disks

          •      A network attached storage (NAS) device is a server connected to a network with 

              the sole purpose of providing storage

        Flash Memory Storage

          •      Flash memory chips are a type of solid state media and contain no moving parts

          •      Solid state drives (SSDs) have several advantages over magnetic hard disks:

–     Faster access time

–     Faster transfer rates

–     Generate less heat and consume less power

–     Last longer

Optical Discs

•      An optical disc consists of a flat, round, portable disc made of metal, plastic, and lacquer that is written and read by a laser

•      Typically store software, data, digital photos, movies, and music

           Read only vs. rewritable

Other Types of Storage

•      Tape is a magnetically coated ribbon of plastic capable of storing large amounts of data and information

•      A tape drive reads and writes data and information on a tape

•      A magnetic stripe card contains a magnetic stripe that stores information

•      A smart card stores data on a thin microprocessor embedded in the card

•      Microfilm and microfiche store microscopic images of documents on a roll or sheet flim.

THANK YOU

The Computer Generations

In the beginning ....

 

 A generation refers to the state of improvement in the development of a product.  This term is also used in the different advancements of computer technology.  With each new generation, the circuitry has gotten smaller and more advanced than the previous generation before it.  As a result of the miniaturization, speed, power, and memory of computers has proportionally increased.  New discoveries are constantly being developed that affect the way we live, work and play.

Pre computers and Early Computers (before 1940s)

•      Experts concluded that ancient civilizations had the ability to count and compute.

•      Abacus – earliest recorded calculating device.

•      Others : slide ruler, mechanical calculator, Punch card tabulating machine (by Dr. Herman Hollerith, 1890s) and Sorter

•      Hollerith’s company eventually became IBM (International Business Machine)

The First Generation:   1940-1950 (The Vacuum Tube Years) 

 

The first generation computers were huge, slow, expensive, and often undependable. In 1946 two Americans, Presper Eckert, and John Mauchly built the ENIAC electronic computer which used vacuum tubes instead of the mechanical switches of the Mark I.  The ENIAC used thousands of vacuum tubes, which took up a lot of space and gave off a great deal of heat just like light bulbs do.  The ENIAC led to other vacuum tube type computers like the EDVAC (Electronic Discrete Variable Automatic Computer) and theUNIVAC I (UNIVersal Automatic Computer).

•      ENIAC [1945]: Designed by Mauchly & Echert, built by US army to calculate trajectories for ballistic shells during Worls War II. Around 18000 vacuum tubes and 1500 relays were used to build ENIAC, and it was programmed by manually setting switches

•      UNIVAC [1950]: the first commercial computer

•      John Von Neumann architecture: Goldstine and Von Neumann took the idea of ENIAC and developed concept of storing a program in the memory. Known as the Von Neumann's architecture and has been the basis for virtually every machine designed since then.

•      Features:

–     Electron emitting devices

–     Data and programs are stored in a single read-write memory

–     Memory contents are addressable by location, regardless of the content itself

–     Machine language/Assemble language

–     Sequential execution 

The Second Generation:  1950-1964 (The Transistor) 

In 1947  three  scientists ,  John Bardeen, William Shockley , and Walter Brattain working at AT&T's Bell Labs invented what would replace the vacuum tube forever.  This invention was the transistor which functions like a vacuum tube in that it can be used to relay and switch electronic signals.

•      First operating Systems: handled one program at a time
                                  

•      On-off switches controlled by electronically.
                                                

•      High level languages (COBOL and FORTRAN)
                           

•      Floating point arithmetic 

The Third Generation: 1964-1974 (Integrated Circuits)

 

The integrated circuit, or as it is sometimes referred to as semiconductor chip, packs a huge number of transistors onto a single wafer of silicon. Robert Noyce of Fairchild Corporation and Jack Kilby of Texas Instruments independently discovered the amazing attributes of integrated circuits.  Placing such large numbers of transistors on a single chip vastly increased the power of a single computer and lowered its cost considerably.

•      Microprocessor chips combines thousands of transistors, entire circuit on one computer chip.

•      Semiconductor memory

•      Multiple computer models with different performance characteristics

•      The size of computers has been reduced drastically 

The Fourth Generation:  1974-Today (The Microprocessor)

      

•      VLSI = Very Large-Scale Integration

•      ULSI = Ultra Large Scale Integration

•      Combines millions of transistors                      

•      Single-chip processor and the single-board computer emerged                  

•      Creation of the Personal Computer (PC)               

•      Use of data communications

•      Massively parallel machine

The Fifth Generation: (now and the future)

                    

•      Based on artificial intelligence - computers can think, reason and learn

•      Primary means of input – voice and touch

•      Different computers construct such as optical computers that utilizes nanotechnology, or as entire general-purpose computers

Computer Architecture

 

•      Processor à center for manipulation and control  
                     
•      Memory à storage for instructions and data for currently executing programs  
                  

•      I/O system à controller which communicate with "external" devices: secondary memory, display devices, networks  
                  

•      Data-path & control à collection of parallel wires, transmits data, instructions, or control signal 

Computer processing power

•      When comparing computers, the power of the computer is important. It is determined by the speed and capacity (size) of each part of the computer.

•      Speed is measured in hertz (Hz) i.e. cycles per second.

•      Capacity is measured in bytes (B) where

                        1 byte = 8 bits (binary digits) = 1 character.

Categories of computers

Categorize based on size, capability and price.

1.     Embedded computers

2.     Mobile devices/ computers

3.     Personal computers

4.     Midrange servers

5.     Mainframes

6.     Supercomputers

1.           Embedded computers

 

•      A miniature computer embedded into a specific product for a specific function.

 

2. Mobile computers 

•      Fits on our lap/ hand, contain built-in computing or Internet capabilities.

3. Personal computers

•      Fully functioning portable or desktop computers, designed for a single user at a time.

4. Midrange Servers

•      Physically likes small cabinet, hosting data and programs available to a small group of users.

5. Mainframe computers 

•      Consume large space and powerful computers used to host a large amount of data and programs available to a wide range of users.

7.   Supercomputers 

•    Extremely powerful computers used for complex computation and processing.

System Unit

•      The system unit is a case that contains electronic components (processor, memory, expansion cards etc) and most storage devices.

System Unit components

•      Processor

•      Memory module

•      Expansion cards

–     Sound card

–     Modem card

–     Video card

–     Network interface card

   •      Ports and Connectors

Motherboard

        

        A motherboard (sometimes alternatively known as the mainboard, system              board,  planar board or logic board, or colloquially, a mobo) is aprinted circuit board (PCB) found in all modern computers which holds many of the crucial components of the system, such as the central processing unit (CPU) and memory, and provides connectors for other peripherals.

           

          These chip packages are available in motherboard…

–     single edge contact (SEC) cartridge

–     dual inline package (DIP)

–     flip chip-PGA  (FC-PGA) package

–     pin grid array (PGA)

Processor

                    

•      The processor is the most important part of the computer. It processes the data and controls the computer.

 

•      Powerful computers used as servers often have more than one processor.

 

•      A set of connectors used for carrying signals between the different parts of a computer is known as a bus.

 

•      Data is transferred constantly between the processor and memory along the system bus.

•      Each part of memory has its own memory address and the processor determines where processed data is stored by sending an address signal along an address bus and data along a data bus.

•      Peripherals: other parts that are connected to the CPU such as input devices, output devices, storage devices and communications devices.

The Central Processing Unit

 

•      Converts data into information

•      Control center

•      Set of electronic circuitry that executes stored program instructions

•      Two parts

–     Control Unit (CU)

–     Arithmetic Logic Unit (ALU)

CPU Components

Control Unit -CU

•      Part of the hardware that is in-charge

•      Directs the computer system to execute stored program instructions

•      Communicates with other parts of the hardware

Arithmetic Logic Unit – ALU

•      Performs arithmetic operations : Addition, Subtraction, Multiplication, Division

•      Performs logical and relational/ comparison operations : AND, OR, NOT, =, > , <

The Architecture of CPU

    

Main Memory

•      There are two types of memory:

–      RAM (random access memory): it holds the program instructions and the data that is being used by the processor – it looses its contents when power is turned off

–      ROM (read only memory): it holds the program instructions and settings required to set up the computer - it does not loose its contents when power is turned off

       Volatility

•      Refers to Memory’s ability to retain its content when electrical power is cut off.

•      There are two types : VOLATILE and NONVOLATILE

•      Volatile memory loses any data as soon as the system is turned off; it requires constant power to remain viable. Most types of RAM fall into this category.

•      Nonvolatile memory does not lose its data when the system or device is turned off. Most types of ROM fall into this category. 

       Random Access Memory(RAM)

        •        RAM can be of two types: Dynamic RAM (DRAM). Static RAM (also called on board cache). 

 

    DRAM :

  •      The storage cell circuits in dynamic RAM chips contain a transistor that acts in much the same way as a mechanical on-off switch. It must be refreshed every 2 milliseconds. A dynamic RAM chip thus provides volatile storage i.e. the data stored are lost in the event of a power failure. 

 

    SRAM : 

  •      Also volatile storage devices, more complicated, cost much more and take up more space for a given storage capacity than do DRAM. Static RAM are faster than DRAM. 

    Read Only Memory(ROM)

                      

•      (ROM) chip is installed by the manufacturer inside the computer. 

•      Also called firm ware, it retains instructions in a permanently accessible nonvolatile form. When the power in the computer is turned off, the instructions stored in ROM are not lost.

•      In addition to ROM, there are also PROMs, EPROMs, and EEPROMs. 

•      PROM stands for programmable read only memory: It works similar to that of ROM. PROM chips are custom made for the user by the manufacturer. The user determines what data and instructions are to be recorded on them. The data on PROM is permanent and cannot be erased. 

•      Erasable programmable read only memory (EPROM), developed as an improvement over PROM. The data on the EPROM can be read with the help of a special device that uses ultra violet light. The data or instructions on the EPROM are erasable and new data can be entered in its place. EPROM functions exactly same as PROM.

•      Electronically erasable programmable read only memory (EEPROM) avoids the inconvenience of having to take chips out of the computer to change data and instructions. Changes can be made electrically under software control. These are used in point of sale terminals to records price related data for products. The prices recorded on them can be easily updated as needed.

    RAM versus ROM

 

     •         ROM (Read only memory):

 

     We can only read the data. Data can’t be written every time, to write the data we need PROM, EPROM, OR EEPROM. ROM is non volatile in nature. The data stored in ROM is permanent in nature. Size of the ROM has nothing to do with processing.

     •         RAM (Random access memory): 

 

     We can read and write data on the chip. RAM has volatile memory. It looses its contents when the power is switched off. Size of the RAM makes difference in the processing i.e., bigger the size of the RAM more is the speed of processing. The data can be read and written at anytime. 

Input

    •      Input is any data and instructions entered into the memory of a computer – can be in the form of programs, commands, and user responses

    The Keyboard

 

     •      A keyboard is an input device that contains keys users press to enter data and instructions into a computer

 

     •      An ergonomic keyboard has a design that reduces the chance of wrist and hand injuries

 

     •      Keyboards on mobile devices typically are smaller and/or have fewer keys

 

     •      Some phones have predictive text input, which saves time when entering text using the phone’s keypad

 

 

  

    Pointing Devices

     •      A pointing device is an input device that allows a user to control a pointer on the screen

 

     •      A pointer is a small symbol on the screen whose location and shape change as a user moves a pointing device

 

     •      Popular pointing devices include:

 

        –     Mouse – can be wired or wireless

        –       Trackball – like an upside down mechanical mouse

        –     Pointing stick – a ‘rubber’ on the keyboard

         –      Touchpad – a small surface sensitive to pressure and motion

        –     Touchscreen – a screen sensitive to pressure and motion

      Digital Cameras

•      A digital camera is a mobile device that allows users to take pictures and store them digitally

•      Types : Studio cameras, Field cameras, point-and-shoot camera

•      Factors affecting the quality of shot : resolution and no. of bits stored in each pixel.

         

       Voice Input

       •      Voice input is the process of entering input (speech, music, sound effect) by speaking into a microphone

       •      Voice recognition is the computer’s capability of distinguishing spoken words

     

       Video Input

      •      Video input is the process of capturing full-motion images and storing them on a        computer’s storage medium

 

      •      A Web cam is a type of digital video camera that enables a user to:

-         Capture video and still images,

-         send email messages with video attachments,

-         add live images to instant messages,

-         broadcast live images over the internet,

-         make video telephone calls.

      •      A video conference is a meeting between two or more geographically separated people

 

 

 

Scanners and Reading Devices:

Optical Scanners

•      Data is captured directly from a source document such as order forms, invoices, paychecks, photos, etc. 

•      Popular types of scanners :

1.     Flatbed

2.     Pen or Handheld

3.     Sheet-fed

4.     Drum

Optical Readers

•      Optical character recognition (OCR) involves reading characters from ordinary documents

•      Optical mark recognition (OMR) reads hand-drawn marks such as small circles or rectangles

•      An OMR device scans the documents and matches the patterns of light

Bar Code Readers

•      A bar code reader, also called a bar code scanner uses laser beams to read bar codes

•      RFID Readers (Radio Frequency Identification) uses radio waves to communicate with a tag placed to an object.

•      RFID is an alternative to barcode readers as it does not require direct contact or line-of-sight transmission.

Magnetic Stripe card readers

•      Magnetic stripe card readers also called magstripe readers, read the magnetic stripe on the back of credit cards, bank cards, entertainment cards etc.

•      The magnetic strip contains information identifying the card issuer and the owner.

MICR

•      MICR (magnetic ink character recognition) devices read text printed with magnetized ink such on a cheque.

Output

•      Output is data that has been processed into a useful form.

•      An output device is any type of hardware component that conveys information to one or more people

Printers

                        

•      A printer produces text and graphics on a physical medium – usually papers.

•      Printed information is called a hard copy, or printout.

•      Two basic types:

o Impact

o Non-impact

•      The sharpness and clarity of printout (or print resolution) is measured in dpi (dots per inch).

Impact printer:

•      Characters/graphics are formed on the paper by physical striking contact between ink ribbon and paper

•      Examples are

            1. dot-matrix printer (continuous paper),

            2. line printer (mainframe/minicomputer)

Non-impact printer:

•      Forms characters and graphics without striking paper

•      Example:

                        1. Ink-jet printers

                        2. photo printers

                              3. Laser printers

Types of storage

1.     Hard disks

2.     Flash Memory storage

3.     Optical discs

4.     Other types :

1.     Tape

2.     Magnetic stripe cards & smart cards

3.     Microfilm & microfiche

             4.     Enterprise storage

        Storage

    v  Storage holds data, instructions, and information for future use.

    v  A storage medium is the physical material on which a computer keeps   

                    data, instructions, and information.

        Hard Disks

          •      A hard disk contains one or more inflexible, circular platters that use magnetic  

             particles to store data, instructions, and information

          •      A head crash occurs when a read/write head touches the surface of a platter

          •      Always keep a backup of your hard disk

          •      RAID (redundant array of independent disks) is a group of two or more 

              integrated hard disks

          •      A network attached storage (NAS) device is a server connected to a network with 

              the sole purpose of providing storage

        Flash Memory Storage

          •      Flash memory chips are a type of solid state media and contain no moving parts

          •      Solid state drives (SSDs) have several advantages over magnetic hard disks:

–     Faster access time

–     Faster transfer rates

–     Generate less heat and consume less power

–     Last longer

Optical Discs

•      An optical disc consists of a flat, round, portable disc made of metal, plastic, and lacquer that is written and read by a laser

•      Typically store software, data, digital photos, movies, and music

           Read only vs. rewritable

Other Types of Storage

•      Tape is a magnetically coated ribbon of plastic capable of storing large amounts of data and information

•      A tape drive reads and writes data and information on a tape

•      A magnetic stripe card contains a magnetic stripe that stores information

•      A smart card stores data on a thin microprocessor embedded in the card

•      Microfilm and microfiche store microscopic images of documents on a roll or sheet flim.

The Computer Generations

In the beginning ....

 

 A generation refers to the state of improvement in the development of a product.  This term is also used in the different advancements of computer technology.  With each new generation, the circuitry has gotten smaller and more advanced than the previous generation before it.  As a result of the miniaturization, speed, power, and memory of computers has proportionally increased.  New discoveries are constantly being developed that affect the way we live, work and play.

Pre computers and Early Computers (before 1940s)

•      Experts concluded that ancient civilizations had the ability to count and compute.

•      Abacus – earliest recorded calculating device.

•      Others : slide ruler, mechanical calculator, Punch card tabulating machine (by Dr. Herman Hollerith, 1890s) and Sorter

•      Hollerith’s company eventually became IBM (International Business Machine)

The First Generation:   1940-1950 (The Vacuum Tube Years) 

 

The first generation computers were huge, slow, expensive, and often undependable. In 1946 two Americans, Presper Eckert, and John Mauchly built the ENIAC electronic computer which used vacuum tubes instead of the mechanical switches of the Mark I.  The ENIAC used thousands of vacuum tubes, which took up a lot of space and gave off a great deal of heat just like light bulbs do.  The ENIAC led to other vacuum tube type computers like the EDVAC (Electronic Discrete Variable Automatic Computer) and theUNIVAC I (UNIVersal Automatic Computer).

•      ENIAC [1945]: Designed by Mauchly & Echert, built by US army to calculate trajectories for ballistic shells during Worls War II. Around 18000 vacuum tubes and 1500 relays were used to build ENIAC, and it was programmed by manually setting switches

•      UNIVAC [1950]: the first commercial computer

•      John Von Neumann architecture: Goldstine and Von Neumann took the idea of ENIAC and developed concept of storing a program in the memory. Known as the Von Neumann's architecture and has been the basis for virtually every machine designed since then.

•      Features:

–     Electron emitting devices

–     Data and programs are stored in a single read-write memory

–     Memory contents are addressable by location, regardless of the content itself

–     Machine language/Assemble language

–     Sequential execution 

The Second Generation:  1950-1964 (The Transistor) 

In 1947  three  scientists ,  John Bardeen, William Shockley , and Walter Brattain working at AT&T's Bell Labs invented what would replace the vacuum tube forever.  This invention was the transistor which functions like a vacuum tube in that it can be used to relay and switch electronic signals.

•      First operating Systems: handled one program at a time
                                  

•      On-off switches controlled by electronically.
                                                

•      High level languages (COBOL and FORTRAN)
                           

•      Floating point arithmetic 

The Third Generation: 1964-1974 (Integrated Circuits)

 

The integrated circuit, or as it is sometimes referred to as semiconductor chip, packs a huge number of transistors onto a single wafer of silicon. Robert Noyce of Fairchild Corporation and Jack Kilby of Texas Instruments independently discovered the amazing attributes of integrated circuits.  Placing such large numbers of transistors on a single chip vastly increased the power of a single computer and lowered its cost considerably.

•      Microprocessor chips combines thousands of transistors, entire circuit on one computer chip.

•      Semiconductor memory

•      Multiple computer models with different performance characteristics

•      The size of computers has been reduced drastically 

The Fourth Generation:  1974-Today (The Microprocessor)

      

•      VLSI = Very Large-Scale Integration

•      ULSI = Ultra Large Scale Integration

•      Combines millions of transistors                      

•      Single-chip processor and the single-board computer emerged                  

•      Creation of the Personal Computer (PC)               

•      Use of data communications

•      Massively parallel machine

The Fifth Generation: (now and the future)

                    

•      Based on artificial intelligence - computers can think, reason and learn

•      Primary means of input – voice and touch

•      Different computers construct such as optical computers that utilizes nanotechnology, or as entire general-purpose computers

Computer Architecture

 

•      Processor à center for manipulation and control  
                     
•      Memory à storage for instructions and data for currently executing programs  
                  

•      I/O system à controller which communicate with "external" devices: secondary memory, display devices, networks  
                  

•      Data-path & control à collection of parallel wires, transmits data, instructions, or control signal 

Computer processing power

•      When comparing computers, the power of the computer is important. It is determined by the speed and capacity (size) of each part of the computer.

•      Speed is measured in hertz (Hz) i.e. cycles per second.

•      Capacity is measured in bytes (B) where

                        1 byte = 8 bits (binary digits) = 1 character.

Categories of computers

Categorize based on size, capability and price.

1.     Embedded computers

2.     Mobile devices/ computers

3.     Personal computers

4.     Midrange servers

5.     Mainframes

6.     Supercomputers

1.           Embedded computers

 

•      A miniature computer embedded into a specific product for a specific function.

 

2. Mobile computers 

•      Fits on our lap/ hand, contain built-in computing or Internet capabilities.

3. Personal computers

•      Fully functioning portable or desktop computers, designed for a single user at a time.

4. Midrange Servers

•      Physically likes small cabinet, hosting data and programs available to a small group of users.

5. Mainframe computers 

•      Consume large space and powerful computers used to host a large amount of data and programs available to a wide range of users.

7.   Supercomputers 

•    Extremely powerful computers used for complex computation and processing.

System Unit

•      The system unit is a case that contains electronic components (processor, memory, expansion cards etc) and most storage devices.

System Unit components

•      Processor

•      Memory module

•      Expansion cards

–     Sound card

–     Modem card

–     Video card

–     Network interface card

   •      Ports and Connectors

Motherboard

        

        A motherboard (sometimes alternatively known as the mainboard, system              board,  planar board or logic board, or colloquially, a mobo) is aprinted circuit board (PCB) found in all modern computers which holds many of the crucial components of the system, such as the central processing unit (CPU) and memory, and provides connectors for other peripherals.

           

          These chip packages are available in motherboard…

–     single edge contact (SEC) cartridge

–     dual inline package (DIP)

–     flip chip-PGA  (FC-PGA) package

–     pin grid array (PGA)

Processor

                    

•      The processor is the most important part of the computer. It processes the data and controls the computer.

 

•      Powerful computers used as servers often have more than one processor.

 

•      A set of connectors used for carrying signals between the different parts of a computer is known as a bus.

 

•      Data is transferred constantly between the processor and memory along the system bus.

•      Each part of memory has its own memory address and the processor determines where processed data is stored by sending an address signal along an address bus and data along a data bus.

•      Peripherals: other parts that are connected to the CPU such as input devices, output devices, storage devices and communications devices.

The Central Processing Unit

 

•      Converts data into information

•      Control center

•      Set of electronic circuitry that executes stored program instructions

•      Two parts

–     Control Unit (CU)

–     Arithmetic Logic Unit (ALU)

CPU Components

Control Unit -CU

•      Part of the hardware that is in-charge

•      Directs the computer system to execute stored program instructions

•      Communicates with other parts of the hardware

Arithmetic Logic Unit – ALU

•      Performs arithmetic operations : Addition, Subtraction, Multiplication, Division

•      Performs logical and relational/ comparison operations : AND, OR, NOT, =, > , <

The Architecture of CPU

    

Main Memory

•      There are two types of memory:

–      RAM (random access memory): it holds the program instructions and the data that is being used by the processor – it looses its contents when power is turned off

–      ROM (read only memory): it holds the program instructions and settings required to set up the computer - it does not loose its contents when power is turned off

       Volatility

•      Refers to Memory’s ability to retain its content when electrical power is cut off.

•      There are two types : VOLATILE and NONVOLATILE

•      Volatile memory loses any data as soon as the system is turned off; it requires constant power to remain viable. Most types of RAM fall into this category.

•      Nonvolatile memory does not lose its data when the system or device is turned off. Most types of ROM fall into this category. 

       Random Access Memory(RAM)

        •        RAM can be of two types: Dynamic RAM (DRAM). Static RAM (also called on board cache). 

 

    DRAM :

  •      The storage cell circuits in dynamic RAM chips contain a transistor that acts in much the same way as a mechanical on-off switch. It must be refreshed every 2 milliseconds. A dynamic RAM chip thus provides volatile storage i.e. the data stored are lost in the event of a power failure. 

 

    SRAM : 

  •      Also volatile storage devices, more complicated, cost much more and take up more space for a given storage capacity than do DRAM. Static RAM are faster than DRAM. 

    Read Only Memory(ROM)

                      

•      (ROM) chip is installed by the manufacturer inside the computer. 

•      Also called firm ware, it retains instructions in a permanently accessible nonvolatile form. When the power in the computer is turned off, the instructions stored in ROM are not lost.

•      In addition to ROM, there are also PROMs, EPROMs, and EEPROMs. 

•      PROM stands for programmable read only memory: It works similar to that of ROM. PROM chips are custom made for the user by the manufacturer. The user determines what data and instructions are to be recorded on them. The data on PROM is permanent and cannot be erased. 

•      Erasable programmable read only memory (EPROM), developed as an improvement over PROM. The data on the EPROM can be read with the help of a special device that uses ultra violet light. The data or instructions on the EPROM are erasable and new data can be entered in its place. EPROM functions exactly same as PROM.

•      Electronically erasable programmable read only memory (EEPROM) avoids the inconvenience of having to take chips out of the computer to change data and instructions. Changes can be made electrically under software control. These are used in point of sale terminals to records price related data for products. The prices recorded on them can be easily updated as needed.

    RAM versus ROM

 

     •         ROM (Read only memory):

 

     We can only read the data. Data can’t be written every time, to write the data we need PROM, EPROM, OR EEPROM. ROM is non volatile in nature. The data stored in ROM is permanent in nature. Size of the ROM has nothing to do with processing.

     •         RAM (Random access memory): 

 

     We can read and write data on the chip. RAM has volatile memory. It looses its contents when the power is switched off. Size of the RAM makes difference in the processing i.e., bigger the size of the RAM more is the speed of processing. The data can be read and written at anytime. 

Input

    •      Input is any data and instructions entered into the memory of a computer – can be in the form of programs, commands, and user responses

    The Keyboard

 

     •      A keyboard is an input device that contains keys users press to enter data and instructions into a computer

 

     •      An ergonomic keyboard has a design that reduces the chance of wrist and hand injuries

 

     •      Keyboards on mobile devices typically are smaller and/or have fewer keys

 

     •      Some phones have predictive text input, which saves time when entering text using the phone’s keypad

 

 

  

    Pointing Devices

     •      A pointing device is an input device that allows a user to control a pointer on the screen

 

     •      A pointer is a small symbol on the screen whose location and shape change as a user moves a pointing device

 

     •      Popular pointing devices include:

 

        –     Mouse – can be wired or wireless

        –       Trackball – like an upside down mechanical mouse

        –     Pointing stick – a ‘rubber’ on the keyboard

         –      Touchpad – a small surface sensitive to pressure and motion

        –     Touchscreen – a screen sensitive to pressure and motion

      Digital Cameras

•      A digital camera is a mobile device that allows users to take pictures and store them digitally

•      Types : Studio cameras, Field cameras, point-and-shoot camera

•      Factors affecting the quality of shot : resolution and no. of bits stored in each pixel.

         

       Voice Input

       •      Voice input is the process of entering input (speech, music, sound effect) by speaking into a microphone

       •      Voice recognition is the computer’s capability of distinguishing spoken words

     

       Video Input

      •      Video input is the process of capturing full-motion images and storing them on a        computer’s storage medium

 

      •      A Web cam is a type of digital video camera that enables a user to:

-         Capture video and still images,

-         send email messages with video attachments,

-         add live images to instant messages,

-         broadcast live images over the internet,

-         make video telephone calls.

      •      A video conference is a meeting between two or more geographically separated people

 

 

 

Scanners and Reading Devices:

Optical Scanners

•      Data is captured directly from a source document such as order forms, invoices, paychecks, photos, etc. 

•      Popular types of scanners :

1.     Flatbed

2.     Pen or Handheld

3.     Sheet-fed

4.     Drum

Optical Readers

•      Optical character recognition (OCR) involves reading characters from ordinary documents

•      Optical mark recognition (OMR) reads hand-drawn marks such as small circles or rectangles

•      An OMR device scans the documents and matches the patterns of light

Bar Code Readers

•      A bar code reader, also called a bar code scanner uses laser beams to read bar codes

•      RFID Readers (Radio Frequency Identification) uses radio waves to communicate with a tag placed to an object.

•      RFID is an alternative to barcode readers as it does not require direct contact or line-of-sight transmission.

Magnetic Stripe card readers

•      Magnetic stripe card readers also called magstripe readers, read the magnetic stripe on the back of credit cards, bank cards, entertainment cards etc.

•      The magnetic strip contains information identifying the card issuer and the owner.

MICR

•      MICR (magnetic ink character recognition) devices read text printed with magnetized ink such on a cheque.

Output

•      Output is data that has been processed into a useful form.

•      An output device is any type of hardware component that conveys information to one or more people

Printers

                        

•      A printer produces text and graphics on a physical medium – usually papers.

•      Printed information is called a hard copy, or printout.

•      Two basic types:

o Impact

o Non-impact

•      The sharpness and clarity of printout (or print resolution) is measured in dpi (dots per inch).

Impact printer:

•      Characters/graphics are formed on the paper by physical striking contact between ink ribbon and paper

•      Examples are

            1. dot-matrix printer (continuous paper),

            2. line printer (mainframe/minicomputer)

Non-impact printer:

•      Forms characters and graphics without striking paper

•      Example:

                        1. Ink-jet printers

                        2. photo printers

                              3. Laser printers

Types of storage

1.     Hard disks

2.     Flash Memory storage

3.     Optical discs

4.     Other types :

1.     Tape

2.     Magnetic stripe cards & smart cards

3.     Microfilm & microfiche

             4.     Enterprise storage

        Storage

    v  Storage holds data, instructions, and information for future use.

    v  A storage medium is the physical material on which a computer keeps   

                    data, instructions, and information.

        Hard Disks

          •      A hard disk contains one or more inflexible, circular platters that use magnetic  

             particles to store data, instructions, and information

          •      A head crash occurs when a read/write head touches the surface of a platter

          •      Always keep a backup of your hard disk

          •      RAID (redundant array of independent disks) is a group of two or more 

              integrated hard disks

          •      A network attached storage (NAS) device is a server connected to a network with 

              the sole purpose of providing storage

        Flash Memory Storage

          •      Flash memory chips are a type of solid state media and contain no moving parts

          •      Solid state drives (SSDs) have several advantages over magnetic hard disks:

–     Faster access time

–     Faster transfer rates

–     Generate less heat and consume less power

–     Last longer

Optical Discs

•      An optical disc consists of a flat, round, portable disc made of metal, plastic, and lacquer that is written and read by a laser

•      Typically store software, data, digital photos, movies, and music

           Read only vs. rewritable

Other Types of Storage

•      Tape is a magnetically coated ribbon of plastic capable of storing large amounts of data and information

•      A tape drive reads and writes data and information on a tape

•      A magnetic stripe card contains a magnetic stripe that stores information

•      A smart card stores data on a thin microprocessor embedded in the card

•      Microfilm and microfiche store microscopic images of documents on a roll or sheet flim.

THANK YOU

The Computer Generations

In the beginning ....

 

 A generation refers to the state of improvement in the development of a product.  This term is also used in the different advancements of computer technology.  With each new generation, the circuitry has gotten smaller and more advanced than the previous generation before it.  As a result of the miniaturization, speed, power, and memory of computers has proportionally increased.  New discoveries are constantly being developed that affect the way we live, work and play.

Pre computers and Early Computers (before 1940s)

•      Experts concluded that ancient civilizations had the ability to count and compute.

•      Abacus – earliest recorded calculating device.

•      Others : slide ruler, mechanical calculator, Punch card tabulating machine (by Dr. Herman Hollerith, 1890s) and Sorter

•      Hollerith’s company eventually became IBM (International Business Machine)

The First Generation:   1940-1950 (The Vacuum Tube Years) 

 

The first generation computers were huge, slow, expensive, and often undependable. In 1946 two Americans, Presper Eckert, and John Mauchly built the ENIAC electronic computer which used vacuum tubes instead of the mechanical switches of the Mark I.  The ENIAC used thousands of vacuum tubes, which took up a lot of space and gave off a great deal of heat just like light bulbs do.  The ENIAC led to other vacuum tube type computers like the EDVAC (Electronic Discrete Variable Automatic Computer) and theUNIVAC I (UNIVersal Automatic Computer).

•      ENIAC [1945]: Designed by Mauchly & Echert, built by US army to calculate trajectories for ballistic shells during Worls War II. Around 18000 vacuum tubes and 1500 relays were used to build ENIAC, and it was programmed by manually setting switches

•      UNIVAC [1950]: the first commercial computer

•      John Von Neumann architecture: Goldstine and Von Neumann took the idea of ENIAC and developed concept of storing a program in the memory. Known as the Von Neumann's architecture and has been the basis for virtually every machine designed since then.

•      Features:

–     Electron emitting devices

–     Data and programs are stored in a single read-write memory

–     Memory contents are addressable by location, regardless of the content itself

–     Machine language/Assemble language

–     Sequential execution 

The Second Generation:  1950-1964 (The Transistor) 

In 1947  three  scientists ,  John Bardeen, William Shockley , and Walter Brattain working at AT&T's Bell Labs invented what would replace the vacuum tube forever.  This invention was the transistor which functions like a vacuum tube in that it can be used to relay and switch electronic signals.

•      First operating Systems: handled one program at a time
                                  

•      On-off switches controlled by electronically.
                                                

•      High level languages (COBOL and FORTRAN)
                           

•      Floating point arithmetic 

The Third Generation: 1964-1974 (Integrated Circuits)

 

The integrated circuit, or as it is sometimes referred to as semiconductor chip, packs a huge number of transistors onto a single wafer of silicon. Robert Noyce of Fairchild Corporation and Jack Kilby of Texas Instruments independently discovered the amazing attributes of integrated circuits.  Placing such large numbers of transistors on a single chip vastly increased the power of a single computer and lowered its cost considerably.

•      Microprocessor chips combines thousands of transistors, entire circuit on one computer chip.

•      Semiconductor memory

•      Multiple computer models with different performance characteristics

•      The size of computers has been reduced drastically 

The Fourth Generation:  1974-Today (The Microprocessor)

      

•      VLSI = Very Large-Scale Integration

•      ULSI = Ultra Large Scale Integration

•      Combines millions of transistors                      

•      Single-chip processor and the single-board computer emerged                  

•      Creation of the Personal Computer (PC)               

•      Use of data communications

•      Massively parallel machine

The Fifth Generation: (now and the future)

                    

•      Based on artificial intelligence - computers can think, reason and learn

•      Primary means of input – voice and touch

•      Different computers construct such as optical computers that utilizes nanotechnology, or as entire general-purpose computers

Computer Architecture

 

•      Processor à center for manipulation and control  
                     
•      Memory à storage for instructions and data for currently executing programs  
                  

•      I/O system à controller which communicate with "external" devices: secondary memory, display devices, networks  
                  

•      Data-path & control à collection of parallel wires, transmits data, instructions, or control signal 

Computer processing power

•      When comparing computers, the power of the computer is important. It is determined by the speed and capacity (size) of each part of the computer.

•      Speed is measured in hertz (Hz) i.e. cycles per second.

•      Capacity is measured in bytes (B) where

                        1 byte = 8 bits (binary digits) = 1 character.

Categories of computers

Categorize based on size, capability and price.

1.     Embedded computers

2.     Mobile devices/ computers

3.     Personal computers

4.     Midrange servers

5.     Mainframes

6.     Supercomputers

1.           Embedded computers

 

•      A miniature computer embedded into a specific product for a specific function.

 

2. Mobile computers 

•      Fits on our lap/ hand, contain built-in computing or Internet capabilities.

3. Personal computers

•      Fully functioning portable or desktop computers, designed for a single user at a time.

4. Midrange Servers

•      Physically likes small cabinet, hosting data and programs available to a small group of users.

5. Mainframe computers 

•      Consume large space and powerful computers used to host a large amount of data and programs available to a wide range of users.

7.   Supercomputers 

•    Extremely powerful computers used for complex computation and processing.

System Unit

•      The system unit is a case that contains electronic components (processor, memory, expansion cards etc) and most storage devices.

System Unit components

•      Processor

•      Memory module

•      Expansion cards

–     Sound card

–     Modem card

–     Video card

–     Network interface card

   •      Ports and Connectors

Motherboard

        

        A motherboard (sometimes alternatively known as the mainboard, system              board,  planar board or logic board, or colloquially, a mobo) is aprinted circuit board (PCB) found in all modern computers which holds many of the crucial components of the system, such as the central processing unit (CPU) and memory, and provides connectors for other peripherals.

           

          These chip packages are available in motherboard…

–     single edge contact (SEC) cartridge

–     dual inline package (DIP)

–     flip chip-PGA  (FC-PGA) package

–     pin grid array (PGA)

Processor

                    

•      The processor is the most important part of the computer. It processes the data and controls the computer.

 

•      Powerful computers used as servers often have more than one processor.

 

•      A set of connectors used for carrying signals between the different parts of a computer is known as a bus.

 

•      Data is transferred constantly between the processor and memory along the system bus.

•      Each part of memory has its own memory address and the processor determines where processed data is stored by sending an address signal along an address bus and data along a data bus.

•      Peripherals: other parts that are connected to the CPU such as input devices, output devices, storage devices and communications devices.

The Central Processing Unit

 

•      Converts data into information

•      Control center

•      Set of electronic circuitry that executes stored program instructions

•      Two parts

–     Control Unit (CU)

–     Arithmetic Logic Unit (ALU)

CPU Components

Control Unit -CU

•      Part of the hardware that is in-charge

•      Directs the computer system to execute stored program instructions

•      Communicates with other parts of the hardware

Arithmetic Logic Unit – ALU

•      Performs arithmetic operations : Addition, Subtraction, Multiplication, Division

•      Performs logical and relational/ comparison operations : AND, OR, NOT, =, > , <

The Architecture of CPU

    

Main Memory

•      There are two types of memory:

–      RAM (random access memory): it holds the program instructions and the data that is being used by the processor – it looses its contents when power is turned off

–      ROM (read only memory): it holds the program instructions and settings required to set up the computer - it does not loose its contents when power is turned off

       Volatility

•      Refers to Memory’s ability to retain its content when electrical power is cut off.

•      There are two types : VOLATILE and NONVOLATILE

•      Volatile memory loses any data as soon as the system is turned off; it requires constant power to remain viable. Most types of RAM fall into this category.

•      Nonvolatile memory does not lose its data when the system or device is turned off. Most types of ROM fall into this category. 

       Random Access Memory(RAM)

        •        RAM can be of two types: Dynamic RAM (DRAM). Static RAM (also called on board cache). 

 

    DRAM :

  •      The storage cell circuits in dynamic RAM chips contain a transistor that acts in much the same way as a mechanical on-off switch. It must be refreshed every 2 milliseconds. A dynamic RAM chip thus provides volatile storage i.e. the data stored are lost in the event of a power failure. 

 

    SRAM : 

  •      Also volatile storage devices, more complicated, cost much more and take up more space for a given storage capacity than do DRAM. Static RAM are faster than DRAM. 

    Read Only Memory(ROM)

                      

•      (ROM) chip is installed by the manufacturer inside the computer. 

•      Also called firm ware, it retains instructions in a permanently accessible nonvolatile form. When the power in the computer is turned off, the instructions stored in ROM are not lost.

•      In addition to ROM, there are also PROMs, EPROMs, and EEPROMs. 

•      PROM stands for programmable read only memory: It works similar to that of ROM. PROM chips are custom made for the user by the manufacturer. The user determines what data and instructions are to be recorded on them. The data on PROM is permanent and cannot be erased. 

•      Erasable programmable read only memory (EPROM), developed as an improvement over PROM. The data on the EPROM can be read with the help of a special device that uses ultra violet light. The data or instructions on the EPROM are erasable and new data can be entered in its place. EPROM functions exactly same as PROM.

•      Electronically erasable programmable read only memory (EEPROM) avoids the inconvenience of having to take chips out of the computer to change data and instructions. Changes can be made electrically under software control. These are used in point of sale terminals to records price related data for products. The prices recorded on them can be easily updated as needed.

    RAM versus ROM

 

     •         ROM (Read only memory):

 

     We can only read the data. Data can’t be written every time, to write the data we need PROM, EPROM, OR EEPROM. ROM is non volatile in nature. The data stored in ROM is permanent in nature. Size of the ROM has nothing to do with processing.

     •         RAM (Random access memory): 

 

     We can read and write data on the chip. RAM has volatile memory. It looses its contents when the power is switched off. Size of the RAM makes difference in the processing i.e., bigger the size of the RAM more is the speed of processing. The data can be read and written at anytime. 

Input

    •      Input is any data and instructions entered into the memory of a computer – can be in the form of programs, commands, and user responses

    The Keyboard

 

     •      A keyboard is an input device that contains keys users press to enter data and instructions into a computer

 

     •      An ergonomic keyboard has a design that reduces the chance of wrist and hand injuries

 

     •      Keyboards on mobile devices typically are smaller and/or have fewer keys

 

     •      Some phones have predictive text input, which saves time when entering text using the phone’s keypad

 

 

  

    Pointing Devices

     •      A pointing device is an input device that allows a user to control a pointer on the screen

 

     •      A pointer is a small symbol on the screen whose location and shape change as a user moves a pointing device

 

     •      Popular pointing devices include:

 

        –     Mouse – can be wired or wireless

        –       Trackball – like an upside down mechanical mouse

        –     Pointing stick – a ‘rubber’ on the keyboard

         –      Touchpad – a small surface sensitive to pressure and motion

        –     Touchscreen – a screen sensitive to pressure and motion

      Digital Cameras

•      A digital camera is a mobile device that allows users to take pictures and store them digitally

•      Types : Studio cameras, Field cameras, point-and-shoot camera

•      Factors affecting the quality of shot : resolution and no. of bits stored in each pixel.

         

       Voice Input

       •      Voice input is the process of entering input (speech, music, sound effect) by speaking into a microphone

       •      Voice recognition is the computer’s capability of distinguishing spoken words

     

       Video Input

      •      Video input is the process of capturing full-motion images and storing them on a        computer’s storage medium

 

      •      A Web cam is a type of digital video camera that enables a user to:

-         Capture video and still images,

-         send email messages with video attachments,

-         add live images to instant messages,

-         broadcast live images over the internet,

-         make video telephone calls.

      •      A video conference is a meeting between two or more geographically separated people

 

 

 

Scanners and Reading Devices:

Optical Scanners

•      Data is captured directly from a source document such as order forms, invoices, paychecks, photos, etc. 

•      Popular types of scanners :

1.     Flatbed

2.     Pen or Handheld

3.     Sheet-fed

4.     Drum

Optical Readers

•      Optical character recognition (OCR) involves reading characters from ordinary documents

•      Optical mark recognition (OMR) reads hand-drawn marks such as small circles or rectangles

•      An OMR device scans the documents and matches the patterns of light

Bar Code Readers

•      A bar code reader, also called a bar code scanner uses laser beams to read bar codes

•      RFID Readers (Radio Frequency Identification) uses radio waves to communicate with a tag placed to an object.

•      RFID is an alternative to barcode readers as it does not require direct contact or line-of-sight transmission.

Magnetic Stripe card readers

•      Magnetic stripe card readers also called magstripe readers, read the magnetic stripe on the back of credit cards, bank cards, entertainment cards etc.

•      The magnetic strip contains information identifying the card issuer and the owner.

MICR

•      MICR (magnetic ink character recognition) devices read text printed with magnetized ink such on a cheque.

Output

•      Output is data that has been processed into a useful form.

•      An output device is any type of hardware component that conveys information to one or more people

Printers

                        

•      A printer produces text and graphics on a physical medium – usually papers.

•      Printed information is called a hard copy, or printout.

•      Two basic types:

o Impact

o Non-impact

•      The sharpness and clarity of printout (or print resolution) is measured in dpi (dots per inch).

Impact printer:

•      Characters/graphics are formed on the paper by physical striking contact between ink ribbon and paper

•      Examples are

            1. dot-matrix printer (continuous paper),

            2. line printer (mainframe/minicomputer)

Non-impact printer:

•      Forms characters and graphics without striking paper

•      Example:

                        1. Ink-jet printers

                        2. photo printers

                              3. Laser printers

Types of storage

1.     Hard disks

2.     Flash Memory storage

3.     Optical discs

4.     Other types :

1.     Tape

2.     Magnetic stripe cards & smart cards

3.     Microfilm & microfiche

             4.     Enterprise storage

        Storage

    v  Storage holds data, instructions, and information for future use.

    v  A storage medium is the physical material on which a computer keeps   

                    data, instructions, and information.

        Hard Disks

          •      A hard disk contains one or more inflexible, circular platters that use magnetic  

             particles to store data, instructions, and information

          •      A head crash occurs when a read/write head touches the surface of a platter

          •      Always keep a backup of your hard disk

          •      RAID (redundant array of independent disks) is a group of two or more 

              integrated hard disks

          •      A network attached storage (NAS) device is a server connected to a network with 

              the sole purpose of providing storage

        Flash Memory Storage

          •      Flash memory chips are a type of solid state media and contain no moving parts

          •      Solid state drives (SSDs) have several advantages over magnetic hard disks:

–     Faster access time

–     Faster transfer rates

–     Generate less heat and consume less power

–     Last longer

Optical Discs

•      An optical disc consists of a flat, round, portable disc made of metal, plastic, and lacquer that is written and read by a laser

•      Typically store software, data, digital photos, movies, and music

           Read only vs. rewritable

Other Types of Storage

•      Tape is a magnetically coated ribbon of plastic capable of storing large amounts of data and information

•      A tape drive reads and writes data and information on a tape

•      A magnetic stripe card contains a magnetic stripe that stores information

•      A smart card stores data on a thin microprocessor embedded in the card

•      Microfilm and microfiche store microscopic images of documents on a roll or sheet flim.