1⃣ Classification by the method of operation (processing)
Computers are classified by the type of data they are designed to process.
📌They are classified into three:
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Computers are classified by the type of data they are designed to process.
📌They are classified into three:
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▶️1. Analog Computers
Analog computers operate by measuring.
💎They deal with continues variables, they don’t
compete directly with numbers, rather, they operate by measuring physical magnitude such as
📌pressure,
📌temperature,
📌voltage,
📌current etc.
🗝They are special purpose computers.
📎Examples:
📌Thermometer,
📌Voltmeter,
📌Speedometer,
📌 Gasoline pomp, etc.
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Analog computers operate by measuring.
💎They deal with continues variables, they don’t
compete directly with numbers, rather, they operate by measuring physical magnitude such as
📌pressure,
📌temperature,
📌voltage,
📌current etc.
🗝They are special purpose computers.
📎Examples:
📌Thermometer,
📌Voltmeter,
📌Speedometer,
📌 Gasoline pomp, etc.
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▶️2. Digital Computers
💎Digital computers deal with discrete variables;
💎They operate by counting rather than measuring.
💎 They operate directly up on numbers (or digits) that represent
📌numbers,
📌letters,
📌or other special symbols.
Digital computers have very high accuracy and speed than the analog ones.
Examples:
📌Abacus,
📌Desk & pocket computers 📌and most general purpose computers
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💎Digital computers deal with discrete variables;
💎They operate by counting rather than measuring.
💎 They operate directly up on numbers (or digits) that represent
📌numbers,
📌letters,
📌or other special symbols.
Digital computers have very high accuracy and speed than the analog ones.
Examples:
📌Abacus,
📌Desk & pocket computers 📌and most general purpose computers
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▶️ 3. Hybrid computers
💎The best features of analog and digital computers can be combined into a single device to form a hybrid computer.
💎A hybrid computer processes the information by collecting input data with analog method, converts it into digital quantities, processes the digital values and
converts the output from digital to analog form.
📎Example:
📌In hospital insensitive-care unit analog devices may measure a patient’s heart
function, temperature and other vital signs. These measurements may then be converted
into numbers and supplied to a digital component in the system.
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💎The best features of analog and digital computers can be combined into a single device to form a hybrid computer.
💎A hybrid computer processes the information by collecting input data with analog method, converts it into digital quantities, processes the digital values and
converts the output from digital to analog form.
📎Example:
📌In hospital insensitive-care unit analog devices may measure a patient’s heart
function, temperature and other vital signs. These measurements may then be converted
into numbers and supplied to a digital component in the system.
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Classification by purpose of application
💎Computers can be applied or used for different purposes.
💎Based upon their application, they
are classified as special purpose or general purpose computers.
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💎Computers can be applied or used for different purposes.
💎Based upon their application, they
are classified as special purpose or general purpose computers.
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▶️ 1. Special purpose computers
💎They are designed to solve a single type of problem, that is their components and their
functions are uniquely adapted to a specific situation involving specific application.
💎Most analog computers are special purpose computers.
📎Example:
📌The public telephone box,
📌Traffic control system,
📌 Ticket machines
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💎They are designed to solve a single type of problem, that is their components and their
functions are uniquely adapted to a specific situation involving specific application.
💎Most analog computers are special purpose computers.
📎Example:
📌The public telephone box,
📌Traffic control system,
📌 Ticket machines
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▶️ 2. General purpose computers.
💎They are designed to solve variety of problems through the use of “store program concept”.
💎A program or set of instructions designed to solve a problem is read and stored into the memory and then executed by the computer one by one.
💎The same computer can be applied to solve another set of problem using different program.
General computers are
more flexible and versatile.
Examples:
📌Microcomputers,
📌Mini computers,
📌Super computers etc.
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💎They are designed to solve variety of problems through the use of “store program concept”.
💎A program or set of instructions designed to solve a problem is read and stored into the memory and then executed by the computer one by one.
💎The same computer can be applied to solve another set of problem using different program.
General computers are
more flexible and versatile.
Examples:
📌Microcomputers,
📌Mini computers,
📌Super computers etc.
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3⃣ Classification by physical size, price, capacity and performance
💎At this stage, by a computer, we mean a general-purpose digital computer. General-purpose digital computers are then classified as follows by their capacity and size.
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💎At this stage, by a computer, we mean a general-purpose digital computer. General-purpose digital computers are then classified as follows by their capacity and size.
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▶️ 1. Super computer
Super computer is the fastest, largest and most potential type of computer.
💎 They have speed of hundreds of millions of operation per second, a primary memory capacity of about
80 million characters, and a secondary memory of capacity of about 20 times its primary
memory.
💎They are multi-user systems in intercontinental range.
💎They can carry out enormously complex scientific calculations.
💎They are used to process huge amount of data and are commonly used in
📌space technology centers,
📌 meteorology stations,
📌 astronomical observatories,
📌 intercontinental communications,
📌airline organizations.
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Super computer is the fastest, largest and most potential type of computer.
💎 They have speed of hundreds of millions of operation per second, a primary memory capacity of about
80 million characters, and a secondary memory of capacity of about 20 times its primary
memory.
💎They are multi-user systems in intercontinental range.
💎They can carry out enormously complex scientific calculations.
💎They are used to process huge amount of data and are commonly used in
📌space technology centers,
📌 meteorology stations,
📌 astronomical observatories,
📌 intercontinental communications,
📌airline organizations.
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▶️ 2. Mainframe computers
💎Smaller than in size and capacity, lower in speed & memory capacity than the super computers.
💎However, they are multi-user systems and handle
hundreds of users, usually used in large organizations.
💎The older ones used punched card for
data input.
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💎Smaller than in size and capacity, lower in speed & memory capacity than the super computers.
💎However, they are multi-user systems and handle
hundreds of users, usually used in large organizations.
💎The older ones used punched card for
data input.
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▶️ 3. Mini computers
💎 have relatively lower speed, can handle multi-users, are smaller in size than the mainframe computers.
💎They use terminals for inputs and output.
💎Mini computers are used in small organizations.
▶️ 4. Microcomputers
💎 Are the most widely used type of computers.
💎They are single users, can
fit on desktops, are of varying capacity and easy to handle. Microcomputers are sometimes referred as personal computers.
💎They have video display unit for output purpose.
💎Data is entered through the keyboard and by the help of floppy disk.
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💎 have relatively lower speed, can handle multi-users, are smaller in size than the mainframe computers.
💎They use terminals for inputs and output.
💎Mini computers are used in small organizations.
▶️ 4. Microcomputers
💎 Are the most widely used type of computers.
💎They are single users, can
fit on desktops, are of varying capacity and easy to handle. Microcomputers are sometimes referred as personal computers.
💎They have video display unit for output purpose.
💎Data is entered through the keyboard and by the help of floppy disk.
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Computers Systems
💎System is a group of components, consisting of subsystems or procedures that work in a coordination fashion to achieve some objective.
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💎System is a group of components, consisting of subsystems or procedures that work in a coordination fashion to achieve some objective.
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Hardware
💎 Is the physical equipment of the computer
you see, you use to and the parts you can touch.
💎Basic Physical components of a computer system.
💎The basic units of a computer system include
📌Central Processing Unit
(CPU),
📌Storage Devices,
📌Input Devices,
📌Output Devices
📌and Communication Bus.
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💎 Is the physical equipment of the computer
you see, you use to and the parts you can touch.
💎Basic Physical components of a computer system.
💎The basic units of a computer system include
📌Central Processing Unit
(CPU),
📌Storage Devices,
📌Input Devices,
📌Output Devices
📌and Communication Bus.
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1⃣Central Processing Unit (CPU) or Processor
📌 Brain of the system
📌 Depending on the instructions
of input devices it performs
operations on the data.
📌 It also controls the flow of data through the
system, directing the data to enter the system, placing it in memory and retrieving it when
required and directing the output.
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📌 Brain of the system
📌 Depending on the instructions
of input devices it performs
operations on the data.
📌 It also controls the flow of data through the
system, directing the data to enter the system, placing it in memory and retrieving it when
required and directing the output.
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💎 The CPU consists of Arithmetical Logic Unit and Control Unit
▶️ ALU (Arithmetical Logic Unit):
It takes logical decision and performs all type of arithmetical calculations.
▶️ CU (Control unit):
📌It controls all the activities of other units of computer system.
📌 It receives instructions from memory unit.
📌 It decodes these instructions.
📌 It decides the routing and storage of these instructions.
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▶️ ALU (Arithmetical Logic Unit):
It takes logical decision and performs all type of arithmetical calculations.
▶️ CU (Control unit):
📌It controls all the activities of other units of computer system.
📌 It receives instructions from memory unit.
📌 It decodes these instructions.
📌 It decides the routing and storage of these instructions.
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2⃣Primary Storage Devices / Main Memory
▶️ RAM (Random Access Memory)
📌 directly accessible by the CU and ALU
📌 Usually referred as Random Access Memory (RAM) because each memory location can be accessed without having to work sequentially through hundreds or even
thousands of memory locations called addresses;
📌 Holds instructions and data elements which are currently being used by the computer.
📌 The data Will be lost when the power is off;
▶️ ROM (Read Only Memory)
📌 This type of memory is integrated into the circuitry of the computer and cannot be altered without altering the computer circuitry.
📌 Used to store basic hardware information.
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▶️ RAM (Random Access Memory)
📌 directly accessible by the CU and ALU
📌 Usually referred as Random Access Memory (RAM) because each memory location can be accessed without having to work sequentially through hundreds or even
thousands of memory locations called addresses;
📌 Holds instructions and data elements which are currently being used by the computer.
📌 The data Will be lost when the power is off;
▶️ ROM (Read Only Memory)
📌 This type of memory is integrated into the circuitry of the computer and cannot be altered without altering the computer circuitry.
📌 Used to store basic hardware information.
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3⃣Secondary Storage Devices/ Auxiliary Memory
Secondary storage can take many forms, which have traditionally included
📌punched cards
📌papers tape
📌magnetic tape
📌magnetic disk
📎HDD (hard disk drive)
📌and magnetic drum.
This storage media are stores data and information permanently.
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Secondary storage can take many forms, which have traditionally included
📌punched cards
📌papers tape
📌magnetic tape
📌magnetic disk
📎HDD (hard disk drive)
📌and magnetic drum.
This storage media are stores data and information permanently.
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Hard Disk Drive(HDD)
💎 is part of a computer system which reads from and writes data on a disk which in turn becomes a file.
📌 A high capacity magnetic disk made up of metal which can be fixed in the system unit of the computer.
📌 Serves as a secondary storage.
📌 The amount of time it takes to retrieve (or store) data from (or to) disk is called the disk access time.
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💎 is part of a computer system which reads from and writes data on a disk which in turn becomes a file.
📌 A high capacity magnetic disk made up of metal which can be fixed in the system unit of the computer.
📌 Serves as a secondary storage.
📌 The amount of time it takes to retrieve (or store) data from (or to) disk is called the disk access time.
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4. Input/Output (IO) Devices
▶️ Input Devices
📌 Is the unit used to enter data into the computer so that it can be processed.
📌 It converts information from a form suitable to human beings to one understandable by the computer.
📌Keyboard
📌Mouse
📌Scanner and etc.
▶️ Output Devices
📌 Used to get data out of a computer so that it can be examined, analyzed or distributed to others.
📌 Convert the result of the only-machine understandable form to a form understandable by human beings.
📌The Visual Display Unit (VDU) or monitor or screen,
📌Printers and etc
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▶️ Input Devices
📌 Is the unit used to enter data into the computer so that it can be processed.
📌 It converts information from a form suitable to human beings to one understandable by the computer.
📌Keyboard
📌Mouse
📌Scanner and etc.
▶️ Output Devices
📌 Used to get data out of a computer so that it can be examined, analyzed or distributed to others.
📌 Convert the result of the only-machine understandable form to a form understandable by human beings.
📌The Visual Display Unit (VDU) or monitor or screen,
📌Printers and etc
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5. Communication Bus
💎 We have seen that there are different components of a computer and each performs a specific function.
💎 But to perform a given task in synchronized form there should be some mechanism of communication.
💎 For this reason, there is an electronic circuit which produces communication path between the different components of a computer system along which
data are transferred, that is Bus.
▶️ Internal Bus
which communicates the different parts of the CPU.
▶️ External Bus
which communicates the CPU with memory and peripheral devices.
💎 The size of the bus determines the speed of
efficiency of the computer.
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💎 We have seen that there are different components of a computer and each performs a specific function.
💎 But to perform a given task in synchronized form there should be some mechanism of communication.
💎 For this reason, there is an electronic circuit which produces communication path between the different components of a computer system along which
data are transferred, that is Bus.
▶️ Internal Bus
which communicates the different parts of the CPU.
▶️ External Bus
which communicates the CPU with memory and peripheral devices.
💎 The size of the bus determines the speed of
efficiency of the computer.
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Computer Software
📌 Software serves as an interface between a user and a computer.
📌 Hardware needs instructions in order to solve problem.
📌 The finite set of instructions (steps) that the computer follows to perform a given job is called a program.
📌 Any program to be executed first it should reside / loaded/ in the memory.
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📌 Software serves as an interface between a user and a computer.
📌 Hardware needs instructions in order to solve problem.
📌 The finite set of instructions (steps) that the computer follows to perform a given job is called a program.
📌 Any program to be executed first it should reside / loaded/ in the memory.
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