Analog Digital Computer :
Analog Computer Digital Computer 1.Analog computers work on the principle of measurement . 1.Analog computers work on the principle of counting. 2.Continuously varying physical parameters such as pressure, distance or velocity, etc are represented by electrical current or voltage signals. 2.It functions in discretely varying quantities which are represented by finite sequence of bits (0 or 1). 3.Continuously varying electrical voltage is fed as input to the analog computer, which is then manipulated using various electronic modules such as inverters, comparators, summers, multipliers and integrators and the results are obtained. Digital computer accepts discrete numbers as input, after processing the result is also discrete and is represented by the output devices. 4.Results are represented by meters, oscilloscopes, etc 4.Results are represented by printer, monitor etc . 5.It is cost provides less precise information. 5.Digital computer is cheap and reliable. 6.Analog computers do not have the ability of digital computers to store data in large quanrtities. 6.It can store data of large volume.
The advantages of Automated Processing over manual Data Processing :
Speed :Since a computer is an electronic device, it operates as the speed of electric flow which is measured in brilions and trilionths of a second.It is faster than any other machine designed to do similar work.
Accuracy :high speed processing by computers is accompanied by high accuracy results.A computer can be considered as 100% accurate.
Automatic Operation :An electric computer can carry out a sequence of many data processing operations without human intervation.
Compact Storage :Electronic data processing systems have the ability to store large amounts of data in a compact and easily retrievable form.
Reduction in paper work :The use of computers for data processing has helped the management of business organizations to cope with increasing problem of paper handling.
Reduced cost :Through the initial investment for installing a computer is high, but it substantially reduces the cost of each of its transaction
Facilitates report preparation :Computer facilitates the preparation of various types of reports required by organizational executives for the purpose of decision making and control.
Reduce the space requirements :The use of computer for office activities reduce the requirements of office space which otherwise is required.
Reduces the manpower requirement :The number of persons required for performing various organizational activities will be reduced by using a computer system.
The disadvantages of Automated Processing over manual Data Processing :
- Installing the computer requires an expensive task of system analysis and design.THere is a demand of computer profssionals to do this.
- Management tends to treat computer like ordinary equipment.Computer pervades the working of the entire organization.
- The initial investment can be very high through this can be mitigated to some extent by the rental and tax concessions
- Since the lead-time of installing is long and the hardware technology is a rapidly advancing field, some of the peripherals/components may be rendered obsolete before even they are installed.
- There is need to obtain stand by facilities at the event of breakdown of any computerized systems.
Example :It can be readily done by communicating the necessary instruction to the concerned staff whereas in a computerized system.
Manual and Automated data processing system :
Manual data processing system Automated data processing system 1.Manual data processing is done by hands and there is no use of computers or any electronic devices . 1.The act of processing data with the use of machines is called automated data processing. 2.It is used for small volume of work for smaller business organizations. 2.It is used for large volume of work for smaller business organizations. 3.It is time consuming to create, store and retrieve information. 3.This method is very fast to create, store and retrieve information. 4.There is no option of automatic operations 4.An electronic computer can carry out a sequence of many automatic data processing operations without human intervention . 5.Information had to written down in ledgers or journals or some sort of index cards. 5.Electronic data processing systems have the ability to store large amounts of data in a compact and easily retrievable form. 6.Paper work is done by human. 6.The computers have eliminated the needs of paper through the storage of data bases and files. 7.Large number of manpower is needed in manual system. 7.The number of persons required for performing various organizational activities will be reduced by using a computer system. 8.It has intelligence to take decisions. 8.It has no intelligence of its own.Operations can be done by the instructions given to it. 9.Errors may occur, so it is less reliable. 9.It is more reliable.
The applications of computer :
In Science :Scientists have been using computers to develop theroies and to analyze and test the data.The high speed and accuracy of the computer allow different scientific analyzes to be carried out.
In Personal and Home Uses :
- Shopping online
- Work from home
- For entertainment and edutainment purpose
In Business/Commerce :
- Computers allow-companies to keep large amounts of information at hand in form of databases
- Makes ordering and tracking resouces quicker and easier
- Buying, selling, marketing and servicing of products and services over computer networks
- An online exchange of value
- Allows people to have meetings from different locations
In Education :Computers have also revolutionized the whole process of education.Currently, the classrooms, libraries and meseums are efficiently utilizing computers to make the education much more interesting.
- The internet allows access to hundreds of online research materials
- Student can get admission and the result in online process
In Medicine and Health Care :There has been an increasing use of computers in the field of medicine.Now, doctors are using computers right from diagosing the illness to monitoring a patient's status during complex surgery.
In Engineering/Architecture/Manufacturing/Industry :The architects and engineers are extensively using computers in designing and drawings.
In Entertainment :Computers has a greater use in entertainment industry.They are used to control the images and sounds.
In Communication :
- People can have teleconferencing and videoconferencing facilities
- E-mail or electronic mail is one of the communication media in whichn computer is used.
In Publishing :Computers have created a field known as desktop publishing(DTP).In DTP, with the help of computer and a laser printer one can perform the publishing job all by oneself.
In Banking :Computers are extensively used in the field of banking and finance.People can use the ATM(automated teller machine) services 24 hours a day to deposit and withdraw cash.Account opening, balance checking money withdrawal, etc operatins can be done by online process.
The analog computer :
The word "Analog" comes from Greek word "Analogous", which means establishing similarities between two quantities.An analog computer is a form of computer that uses the continuously-changable aspects of physical phenomena such as electric, mechanical, hydraullic quantities.
Continuously varying physical parameters such as pressure, distance or velocity is fed as input to the analog computer and after processing the results are represented by meters, oscilloscopes.
Example :Automatic Speedometer
Componenet of Analog computer :
- Precision resistors and capacitors
- Operational amplifiers
- Fixed-function generators
The core mathematical operations used in an electric analog computer are :
- Integration with respect to time
- Division although multiplication is much preferred
The digital computer :
- Digital computer work on the principle of counting
- It functions in discretely varying quantities which are represented by finite sequence of bits(0 or 1)
- Electricity can be controlled in many different ways but the easiest way is -to switch ON = 1 and to switch OFF = 0, these represent the binary system.
- Digital computers accepts discrete numbers as input after processing the result is also discrete and is represented by the output devices such as monitors, printers, etc.
Example :Microcomputer, minicomputer, etc
- Digital computer is cheap and reliable because it uses binary system
- Analog computers do not have the ability of digital computers to store data in large quantities, nor do they have the comprehensive logical facilities afforded by programming digital machines.
The hybrid computer :
- An analog input is converted into digits.
- The information then can be sent into a standard digital computer for further computation.
In any case, the hybrid computer is usually substantially faster than a digital compute, but can supply a far more precise computation than an analog computer.It is useful for real-time applications such as a high frequency phased array radar, a weather system computation, process control, etc.
The Micro Computer :
Microcomputers are microprocessor-based computers.A microprocessor is an integrated circuit(IC) with milions of trasitor.A microcomputer consists of :
- Input devices
- Output devices
- Processing unit-microprocessor
- Memory unit
Microcomputers are also known as personal computers and are the ones mostly found in big and small office, they are normally standalone computers known PC, or Desktop Computers.Micro Computers are small and expensive designed for individual use.Some manufacturing companies of micro computers include HP Computers, Dell Computers, IBM Computers and many more.
Characteristics of Micro Computer :
- Small computer based on a microprocessor
- A personal computer designed to meet the needs of an individual; provides a variety of applications
- Provides access to a wide variety of computing applications, such as word processing, photo editing, email and internet
The Mini Computer :
Mini computers are modidsized computers capable of supporting from 74-200 users simultaneously. Mini pc is mainly used as depatmental computers for data processing in large organization or governmental institutions like hospitals. Mini computers are physically smaller, less expensive and small storage capacity than mainframe.
- It is called midrange computers
- Its power is between mainframe and desktop
- It can handle hundreds of users
- Users access through a terminal
- Used in smaller organizations
The Mainframe Computer :
- Large and expensive computer capable of simultaneously processing data for hundreds or thousands of users
- Used to store, manage and process large amounts of data that need to be reliable and secure
- Mainly used by large organizations as banks, insurance, companies, railways etc where a large number of users need to share a common computing facility
- Typical mainframe system looks like a row of large file cabinates and needs a large room.
The Super Computer :
- Most powerful and most expensive computers available at a given time
- Primarily used for processing complex scientific applications that require enormous processing power
- Handle large and complex calculations
- Process trilions of operations per second
- Found in research organizations
- These computers are used in multiprocessing, multitasking and parallel processing for different tasks
The Workstation Computer :
- Powerfull desktop computers designed to meet the computing needs of engineers, architects and other professionals
- Provides greter processing power, larger storage and better graphics display facility than PCs
- Commonly used for computer-aided design, multimedia applications, simulation of complex scientific and engineering problems and visualization
- Generally run the UNIX operating system or a variation of it
- Operating system is generally designed to support multi user environment
The Desktop Computer :
- Small computer based on a microprocessor
- Non-portable general purpose computers that fits on a normal size office table
- Designed to meet personal computing needs of individuals
- Often used by children and adults for education and entertainment also
- Two common modelels of PCs are desktop model and tower model
- Generally used by one person at a time supports multitasking
- Popular OS are MS-DOS, MS-Windows-NT, Linux, UNIX
- Provides access to a wide variety of computing applications such as word processing, photo editing, e-mail and internet
The Laptop Computer :
- Portable computers mainly meant for use by people who need computing resource wherever they go
- Weight around 2 kg only
- Approximately of the size of an 8.5*11 inch notebook abd can easily fit inside a briefcase
- Comfortably placed on ones lap while being used.Hence, they are also called laptop PC
- Lid with display screen is fordable in a manner that when not in use it can be folded to flush with keyboard to convert the system into notebook form
- Portable compact computer that runs on a wall outlet or battery unit with all components in one unit.All components(keyboard, mouse) are in one compact unit
- Usually more expensive than a comparable desktop
- Sometimes called a notebook