Generation of Computers
It is important to realize that major changes and trends in computer  systems have occurred during the major  stages-or generations-of  computing, and will continue into the future. The first generation of  computers developed in the early 1950s, the second generation blossomed  during the late 1960s, the third generation took computing into the  1970s, and the fourth generation has been the computer technology of the  1980s and 1990s. A fifth generation of computers that accelerates the  trends of the previous generations is expected to evolve as we enter the  21st century. Notice that computers continue to become smaller, faster,  more reliable, less costly to purchase and maintain, and more  interconnected within computer networks.
First-generation computing involved massive computers using hundreds or  thousands of vacuum tubes for their processing and memory circuitry.  These large computers generated enormous amounts of heat; their vacuum  tubes had to be replaced frequently. Thus, they had large electrical  power, air conditioning, and maintenance requirements. First-generation  computers had main memories of only a few thousand characters and  millisecond processing speeds. They used magnetic drums or tape for  secondary storage and punched cards or paper tape as input and output  media.
Second-generation computing used transistors and other solid-state,  semiconductor devices that were wired to circuit boards in the  computers. Transistorized circuits were much smaller and much more  reliable, generated little heat, were less expensive, and required less  power than vacuum tubes. Tiny magnetic cores were used for the  computer’s memory, or internal storage. Many second-generation computers  had main memory capacities of less than 100 kilobytes and microsecond  processing, speeds. Removable magnetic disk packs were introduced, and  magnetic tape merged as the major input, output, and secondary storage  medium for large computer installations.
Third-generation computing saw the development of computers that used  integrated circuits, in which thousands of transistors and other circuit  elements are etched on tiny chips of silicon. Main memory capacities  increased to several megabytes and processing speeds jumped to millions  of instructions per second (MIPS) as telecommunications capabilities  became common. This made it possible for operating system programs to  come into widespread use that automated and supervised the activities of  many types of peripheral devices and processing by mainframe computers  of several programs at the same time, frequently involving networks of  users at remote terminals. Integrated circuit technology also made  possible the development and widespread use of small computers called  minicomputers in the third computer generation.
Fourth-generation computing relies on the use of LSI (large-scale  integration) and VLSI (very-large-scale integration) technologies that  cram hundreds of thousands or millions of transistors and other circuit  elements on each chip. This enabled the development of microprocessors,  in which all of the circuits of a CPU are contained on a single chip  with processing speeds of millions of instructions per second. Main  memory capacities ranging from a few megabytes to several gigabytes can  also be achieved by memory chips that replaced  magnetic core memories.  Microcomputers, which use microprocessor CPUs and a variety of  peripheral devices and easy-to-use software packages to form small  personal computer (PC), systems or client/server networks of linked PCs  and servers, are a hallmark of the fourth generation of computing, which  accelerated the downsizing of computing systems.
Whether we are moving into a fifth generation of computing is a subject  of debated since the concept of generations may no longer fit the  continual, rapid changes occurring in computer hardware, software, data,  and networking technologies. But in any case, we can be sure that  progress in computing will continue to accelerate, and that the  development of Internet-based technologies and applications will be one  of the major forces driving computing into the 21st century.
Computer System  Concepts and Components
The Computer System Concept:
A computer is more than a high-powered collection of electronic devices  performing a variety of information processing chores. A computer is a  system, an interrelated combination of components that performs the  basic system functions of input, processing, output, storage, and  control, thus providing end users with a powerful information processing  tool. Understanding the computer as a computer system is vital to the  effective use and management of computers.
A computer is system of hardware devices organized according to the following system functions.
Input:
The input devices of a computer system include keyboards, touch screens, pens, electronic mice, optical scanners, and so on.
Processing:
 The central processing unit( CPU) is the main processing component of a  computer system. (In microcomputers, it is the main microprocessor.) In  particular, the electronic circuits of the arithmetic-logic unit one of  the CPU’s major components, perform the arithmetic and logic functions  required in computer processing.
Output:
 The output devices of a computer system include video display units,  printers, audio response units , and so on, They convert electronic  information produced by the computer system into human intelligible form  for presentation to end users.
Storage:
 The storage function of a computer system takes place in the storage  circuits of the computer’s primary storage unit, or memory, and in  secondary storage devices such as magnetic disk and tape units. These  devices store data and program instructions needed for processing.
Control:
 The control unit of the CPU is the control component of a computer  system. Its circuits interpret computer program instructions and  transmit directions to the other components of the computer system.
Central Processing Unit:
The central processing unit is the most important hardware component of a  computer system. It is also known as the CPU, the central processor or  instruction processor, and the main microprocessor in a microcomputer.  Conceptually, the circuitry of a CPU can be subdivided into two major  subunits the arithmetic-logic unit and the control unit. The CPU also  includes circuitry for devices such as registers and cache memory for  high speed, temporary storage of instruction  operations, input/output,  and telecommunications support.
The control unit obtains instructions from software segments stored in  the primary storage unit and interprets them. Then it transmits  electronic signals to the other components of the computer system to  perform required operations. The arithmetic-logic unit performs required  arithmetic and comparison operations .A computer can make logical  changes from one set of program instructions to another (e.g, overtime  pay versus regular pay calculations) based on the results of comparisons  made in the ALU during processing.
Main Memory and Primary Storage Unit:
A computer’s primary storage unit is commonly called main memory, and  holds data and program instructions between processing steps and  supplies them to the control unit and arithmetic-logic unit during  processing. Most of a computer’s memory consists of microelectronic  semiconductor memory chips known as RAM (random access memory ). The  contents of these memory chips can be instantly changed to store new  data. Other, more permanent memory chips called ROM (read only memory)  may also be used.
Secondary storage devices like magnetic disks and optical disks are used  to store data and programs and thus greatly enlarge the storage  capacities of computer system. Also, since memory circuits typically  lose their contents when electric power is turned off, most secondary  storage media provide a more permanent type of storage. However the  contents of hard disk drives floppy disks, CD-ROM disks, and other  secondary storage media cannot be processed without first being brought  into memory. Thus secondary storage devices play a supporting role to  the primary storage of a computer system.
Multiple Processors:
Many current computers, from microcomputers to large mainframes, use  multiple processors for their processing functions. Instead of having  one CPU with a single control unit and arithmetic-logic unit, the CPUs  of these computers contain several type of processing units. Let’s  briefly look at the major types of such multiprocessor designs.
A support processor design relies on specialized microprocessors to help  the main CPU perform a variety of functions. These microprocessors may  used for input/output, memory management, arithmetic computations,  multimedia processing, and telecommunications, thus freeing the main  processor to do the primary job of executing program instructions For  example, many microcomputers rely on support microprocessors such as  arithmetic co-processing load on their main microprocessors. A large  computer may use support microprocessors called channels to control the  movement of data between the CPU and input/output devices. Advanced  microprocessor designs integrate the functions of several support  processors on a single main microprocessor.
A coupled processor design uses multiple CPUs or main microprocessors to  do multiprocessing, that is, executing more than one instruction at the  same time. Some configurations provide a fault-tolerant capability in  which multiple CPUs provide a built-in backup to each other should one  of them fail.
A parallel processor design uses a group of instruction processors to  execute several program instructions at the same time. Some times,  hundreds or thousands of processors are organized in clusters or  networks in massively parallel processing (MPP) computers. Other  parallel processor designs are based on simple models of the human brain  called neural networks. All of these systems can execute many  instructions at a time in parallel. This is a major departure from the  traditional design of current computers, called the Von Neuman design,  which executes instructions serially (one at a time). Though difficult  to program, many experts consider parallel processor systems the key to  providing advanced capabilities to future generations of computers.
RISC Processors:
    Many advanced technical workstations and other computers rely on a  processor design called RISC (reduced instruction set computer). This  contrasts with most current computers that use CISC (complex instruction  set computer) processors. RISC processor designs optimize a CPU’s  processing speed by using a smaller instruction set. That is, they use a  smaller number of the basic machine instruction that a processor is  capable of executing. By keeping the instruction set simpler than CISC  processors and using more complex software, a RISC processor can reduce  the time needed to execute program instructions.
Computer Processing Speeds:
Computer operating speeds that were formerly measured in milliseconds  (thousands of a second) and microseconds (millionths  of a second) are  now in the nanosecond (billionth of a second) range, with picosecond  (trillionth of a second) speed being attained by some computers. Such  speeds seem almost incomprehensible. For example, an average person  taking one step each nanosecond would circle the earth above 20 times in  one second. Many microcomputers and midrange computers, and most  mainframe computers, operate in the nanosecond range, and can thus  process program instructions at million instructions per second (MIPS)  speeds. Another measure of processing speed is megahertz (MHs), or  millions of cycles per second. It is commonly called the clock speed of a  microprocessor, sine it is used to rate microprocessors by the speed of  their timing circuits or internal clock.
However, megahertz, ratings can be misleading indicators of the  effective processing speed of microprocessors as measured in MIPS and  other measures. That’s because processing speed depends on a variety of  factors besides a microprocessor’s clock speed. Important examples  include the size of circuitry paths, or busses, that interconnect  microprocessor components, the capacity of instruction processing  registers, the use of high-speed memory caches, and the use of  specialized microprocessors such as a math co-processor to do arithmetic  calculations faster. For example, Intel’s Pentium microprocessor runs  at 66 to 200 MHz and is rated at over 100 MIPS, which the Pentium Pro  microprocessor has a top processing rating of over 200 MIPS at similar  megahertz speeds.
Computer Storage Fundementals and Devices
Data and information must be stored until needed using a variety of  storage methods. There are many types of storage media and devices.
Computer Storage Fundamentals:
Data are processed and stored in a computer system through the presence  or absence of electronic or magnetic signals in the computer’s circuitry  or in the media it uses. This is called a “two-state” or binary  representation of data, since the computer and the media can exhibit  only two possible states or conditions. For example, transistors other  semiconductor circuits are either in a conducting or nonconducting  state. Media such as magnetic disks and tapes indicate these two states  by having magnetized spots whose magnetic fields have one of two  different directions, or polarities. This binary characteristic of  computer circuitry and media is what makes the binary number system the  basis for representing data in computers. Thus, for electronic circuits,  the conducting (ON) state represents the number one, while the  nonconducting (OFF) state represents the number zero. For magnetic  media, the magnetic field of a magnetized sport in one direction  represents a one, while magnetism in the other direction represents a  zero.
The smallest element of data is called a bit, which can have a value of  either zero or one. The capacity of memory chips is usually expressed in  terms of bits. A byte is a basic grouping of bits that the computer  operates as a single unit. Typically, it consists of eight bits and  represents one character of data in most computer coding schemes. Thus,  the capacity of a computer’s memory and secondary storage device is  usually expressed in terms of bytes. Computer codes such as ASCII  (American Standard Code for Information Interchange) use various  arrangements of bits to form bytes that represent the numbers zero  through nine, the letters of the alphabets, and many other characters.
Storage capacities are frequently measured in kilobytes (KB), megabytes  (MB), gigabytes (GB), or terabytes (TB). Although kilo means 1,000 in  the metric system, the computer industry uses K to represents 1,024 or  (210) storage positions. Therefore, a capacity of 10 megabytes, for  example, is really 10,485,760 storage positions, rather than 10 million  positions. However, such differences are frequently disregarded in order  to simplify descriptions of storage capacity. Thus, a megabyte is  roughly 1 million bytes of storage, while a gigabyte is roughly 1  billion bytes and a terabyte represents about 1 trillion bytes.
Direct and Sequential Access:
Primary storage media such as semiconductor memory chips are called  direct access or random access memories (RAM). Magnetic disk devices are  frequently called direct access storage devices (DASDs). On the other  hand, media such as magnetic tapes are known as sequential access  devices.
The term direct access and random access describe the same concept. They  mean that an element of data or instructions (such as a byte or word)  can be directly stored and retrieved by selecting and using any of the  locations on the storage media. They also mean that each storage  position (1) has a unique address and (2) can be individually accessed  in approximately the same length of time without having to search  through other storage positions. For example, each memory cell on a  microelectronic semiconductor RAM chip can be individually sensed or  changed in the same length of time. Also any data record stored on a  magnetic or optical disk can be accessed directly in approximately the  same time period.
Sequential access storage media such as magnetic tape do not have unique  storage addresses that can be directly addressed. Instead, data must be  stored and retrieved using a sequential or serial process. Data are  recorded one after another in a predetermined sequence (such as in  numeric order) on a storage medium. Locating an individual item of data  requires searching much of the recorded data on the tape until the  desired item is located.
Semiconductor Memory:
The primary storage (main memory) of your computer consists of  microelectronic semiconductor memory chips. Memory chips with capacities  of 4 million bits (4 megabits) and 16 megabytes or more of memory chips  can be added to your PC to increase its memory capacity. Specialized  memory can help improve your computer’s performance. Examples include  external cache memory of 256 or 512 kilobytes to help your  microprocessor work faster, or a video graphics accelerator card with 2  megabytes or more of RAM for faster and clearer video performance.  Removable credit-card-size and smaller “flash memory” RAM cards can also  provide several megabytes of erasable direct access storage for PDAs or  handheld PCs.
Some of the major attractions of semiconductor memory are its small  size, great speed, and shock and temperature resistance. One major  disadvantage of most semiconductor memory is its volatility.  Uninterrupted electric power must be supplied or the contents of memory  will be lost. Therefore, emergency transfer to other devices or standby  electrical power (through battery packs or emergency generators) is  required if data are to be saved. Another alternative is to permanently  “burn in” the contents of semiconductor devices so that they cannot be  erased by a loss of power.
Thus, there are two basic types of semiconductor memory: random access memory (RAM) and read only memory (ROM).
RAM: 
random access memory. These memory chips are the most widely used  primary storage medium. Each memory position can be both sensed (read)  and changed (written), so it is also called read/write memory. This is a  volatile memory.
ROM: 
read only memory. Nonvolatile random access memory chips are used for  permanent storage. ROM can be read but not erased or overwritten.
Frequently used control instructions in the control unit and programs in  primary storage (such as parts of the operating system) can be  permanently burned in to the storage cells during manufacture. This is  sometimes called firmware. Variations include PROM (programmable read  only memory) and EPROM (erasable programmable read only memory) that can  be permanently or temporarily programmed after manufacture.
Magnetic Disk Storage:
Magnetic disks are the most common form of secondary storage for your  computer system. That’s because they provide fast access and high  storage capacities at a reasonable cost. Magnetic disk drives contain  metal disks that are coated on both sides with an iron oxide recording  material. Several disks are mounted together on a vertical shaft, which  typically rotates the disks at speeds of 3,600 to 7,600 revolutions per  minute (rpm). Electromagnetic read/write heads are positioned by access  arms between the slightly separated disks to read and write data on  concentric, circular tracks. Data are recorded on tracks in the form of  tiny magnetized spots to form the binary digits of common computer  codes. Thousands of bytes can be recorded on each tracks, and there are  several hundred data tracks on each disk surface, thus providing you  with billions of storage positions for your software and data.
Types of Magnetic Disks:
There are several types of magnetic disk arrangements, including  removable disk cartridges as well as fixed disk units. Removable disk  devices are popular because they are transportable and can be used to  store backup copies of your data offline for convenience and security.
Floppy disks or magnetic diskettes, consist of polyester film disks  covered with an iron oxide compound. A single disk is mounted and  rotates  freely inside a protective flexible or hard plastic jacket,  which has access openings to accommodate the read/write head of a disk  drive unit. The 31/2 inch floppy disk, with capacities of 1.44  megabytes, is the most widely used version, with a newer LS-120  technology offering 120 megabytes of storage.
Hard disk drives combine magnetic disks, access arms, and read/write  heads into a sealed module. This allows higher speeds, greater  data-recording densities, and closer tolerances within a sealed, more  stable environment. Fixed or removable disk cartridge versions are  available. Capacities of hard drives range from several hundred  megabytes to gigabytes of storage.
RAID:
 Disk arrays of interconnected microcomputer hard disk drives have  replaced large-capacity mainframe disk drives to provide many gigabytes  of online storage. Known as RAID (redundant arrays of independent  disks), they combine from 6 to more than 100 small hard disk drives and  their control microprocessors into a single unit. RAID units provide  large capacities with high access speeds since data are accessed in  parallel over multiple paths from many disks. RAID units also provide a  fault tolerant capability, since their redundant design offers multiple  copies of data on several disks. If one disk fails, data can be  recovered from backup copies automatically stored on other disks.
Magnetic Tape Storage:
Magnetic tape is still being used as a secondary storage medium in  business applications. They read/write heads of magnetic tape drives  record data in the form of magnetized spots on the iron oxide coating of  the plastic tape. Magnetic tape devices include tape reels and  cartridges in mainframes and midrange systems, and small cassettes or  cartridges for PCs. Magnetic tape cartridges have replaced tape reels in  many applications, and can hold over 200 megabytes.
One growing business application of magnetic tape involves the use of  36-track magnetic tape cartridges in robotic automated drive assemblies  that can hold hundreds of cartridges. These devices serve as slower, but  lower cost, storage to supplement magnetic disks to meet massive data  warehouse and other business storage requirements. Other major  applications for magnetic tape includes long-term archival storage and  backup storage for PCs and other systems.
Optical Disk Storage:
Optical disks are a fast-growing storage medium. The version for use  with micro computers is called CD-ROM (compact disk- read only memory).  CD-ROM technology use 12-centimeter (4.7 inch) compact disks (CDs)  similar to those used in stereo music systems. Each disk can store more  than 600 megabytes. That’s the equivalent of over 400 1.44 megabyte  floppy disks or more than 300,000 double-spaced pages of text. A laser  records data by burning permanent microscopic pits in a spiral track on a  master disk from which compact disks can be mass produced. Then CD-ROM  disk drives use a laser device to read the binary codes formed by those  pits.
CD-R (compact disk – record able) is another optical disk technology. It  enables computers with CD-R disk drive units to record their own data  once on a CD, then be able to read the data indefinitely. The major  limitation of CD-ROM and CD-R disks is that recorded data cannot be  erased. However, CD-RW
(CD-rewritable) optical disk systems have now become available which  record and erase data by using a laser to heat a microscopic point on  the disk’s surface. In CD-RW versions using magneto optical technology, a  magnetic coil changes the spot’s reflective properties from one  direction to another, thus recording a binary one or zero. A laser  device can then read the binary codes on the disk by sensing the  direction of reflected light.
Optical disk capacities and capabilities have increased dramatically  with the emergence of an optical disk technology called DVD (digital  video disk or digital versatile disk), which can hold from 4.0 to 8.5  gigabytes of multimedia data on each side of a compact disk. The large  capacities and high quality images and sound of DVD technology are  expected to eventually replace CD-ROM and CD-RW technologies for data  storage, and promise to accelerate the sue of DVD drives for multimedia  products that can be used in both computers and home entertainment  systems.
Blu-Ray and HD-DVD are two new optical storage technologies that fight  as the successor of DVD. Both HD-DVD and Blu-ray are high-definition  optical disc formats, incompatible with each other. They were meant to  replace the existing DVD format, which was and still is used by a large  user community. HD-DVDs and Blu-ray discs are similar in terms of the  higher storage capacities and a superior picture quality offered by  them. Their storage capacities are higher than those of CDs and DVDs.  However, a single layer HD-DVD can store 15 GB data whereas a  single-layer Blu-ray disc stores 25 GB data.
Major Types of  Computer Systems
Microcomputer Systems:
Microcomputers are the most important category of computer systems for  end users. Though usually called a personal computer, or PC, a  microcomputer is much more than a small computer for use by an  individual. The computing power of microcomputers now exceeds that of  the mainframes of previous computer generations at a fraction of their  cost. Thus, they have become powerful networked professional work  stations for end users in business.
Microcomputers come in a variety of sizes and shapes for a variety of  purposes. For example, PCs are available as handhled, notebook, laptop,  portable, desktop, and floor-standing models.  Based on their use, they  include home, personal, professional, workstation, and multi-user  systems. Most microcomputers are desktops designed to fit on an office  desk, or notebooks for those who want a small, portable PC for their  work activities.
Some microcomputers are powerful workstation computers (technical  work-stations) that support applications with heavy mathematical  computing and graphics display demands such as computer-aided design  (CAD) in engineering, or investment and portfolio analysis in the  securities industry. Other microcomputers are used as network servers.  They are usually more powerful microcomputers that coordinate  telecommunications and resource sharing in small local area networks  (LANs), and Internet and intranet Web sites. Another important  microcomputer category includes handheld microcomputer devices known as  personal digital assistants (PDAs), designed for convenient mobile  communications and computing. PDAs use touch-screens, pen-based  handwriting recognition of keyboards to help mobile workers send and  receive E-mail and exchange information such as appointments, to do  lists, and scales contacts with their desktop PCs or Web servers.
Multimedia Computer Systems:
Multimedia PCs are designed to present you with information in a variety  of media, including text and graphics displays, voice and other  digitized audio, photographs, animation, and video clips. Mention  multimedia, and many people think of computer video games, multimedia  encyclopedias, educational videos, and multimedia home pages on the  World Wide Web. However, multimedia systems are widely used in business  for training employees, educating customers, making sales presentations,  and adding impact to other business presentations.
The basic hardware and software requirements of a multimedia computer  system depend on whether you wish to create as well as enjoy multimedia  presentations. Owners of low-cost multimedia PCs marketed for home used  do not need authoring software or high-powered hardware capacities in  order to enjoy multimedia games and other entertainment and educational  multimedia products. These computers come equipped with a CD-ROM drive,  stereo speakers, additional memory, a high-performance processor, and  other multimedia processing capabilities.
People who want to create their own multimedia production may have to  spend several thousand dollars to put together a high-performance  multimedia authoring system. This includes a high-resolution color  graphics monitor, sound and video capture boards, a high-performance  microprocessor with multimedia capabilities, additional megabytes of  memory, and several gigabytes of hard disk capacity. Sound cards and  video capture boards are circuit boards that contain digital signal  processors (DSPs) and additional megabytes of memory for digital  processing of sound and video. A digital camera, digital video  camcorder, optical scanner, and software such as authoring tools and  programs for image editing and graphics creation can add several  thousand dollars to the star-up costs of a multimedia authoring system.
Midrange Computer Systems:
Midrange Computers, including minicomputers and high-end network  servers, are multi-user systems that can manage network of PCs and  terminals. Though not as powerful as mainframe computers, they are less  costly to buy, operate, and maintain than mainframe systems, and thus  meet the computing needs of many organizations.
Midrange computers first became popular as minicomputers for scientific  research, instrumentation systems, and industrial process monitoring and  control. Minicomputers could easily handle such uses because these  applications are narrow in scope and do not demand the processing  versatility of mainframe systems. Thus, midrange computers serve as  industrial process-control and manufacturing plant computers, and they  still play a major role in computer-aided manufacturing (CAM). They can  also take the form of powerful technical workstations for computer-aided  design (CAD) and other computation and graphics-intensive applications.  Midrange computers are also used as front-end computers to assist  mainframe computers in telecommunication processing and network  management.
Midrange computers have become popular as powerful network servers to  help manage large Internet Web sites, corporate intranets and extranets,  and client/server networks. Electronic commerce and other business uses  of the Internet are popular high-end server applications, as are  integrated enterprise wide manufacturing, distribution and financial  applications. Other applications, like data warehouse management, data  mining, and online analytical processing.
Mainframe Computer Systems:
Mainframe computes are large, fast, and powerful computer systems. For  example, mainframes can process hundreds of million instructions per  second (MIPS). Mainframes also have large primary storage capacities.  Their main memory capacity can range from hundreds of megabytes to many  gigabytes of primary storage. And mainframes have slimmed down  drastically in the last few years, dramatically reducing their  air-conditioning needs, electrical power consumption, and floor space  requirements, and thus their acquisition and operating costs. Most of  these improvements are the result of a move from water-cooled mainframes  to a new CMOS air-cooled technology for mainframe systems.
Thus, mainframe computers continue to handle the information processing  needs of major corporations and government agencies with many employees  and customers or with complex computational problems. For example, major  international banks, airlines, oil companies, and other large  corporations process millions of sales transactions and customer  inquiries each day with the help of large mainframe systems. Mainframes  are still used for computation-intensive applications such as analyzing  seismic data from oil field explorations or simulating flight conditions  in designing aircraft. Mainframes are also widely used as super server  for the large client/server network and high-volume Internet Web sites  of large companies.
Supercomputer Systems:
The term supercomputer describes a category of extremely powerful  computer systems specifically designed for scientific ,engineering, and  business applications requiring extremely high speeds for massive  numeric computations. The market for supercomputers includes government  research agencies, large universities, and major corporations. They use  supercomputers for applications such as global weather forecasting,  military defense systems, computational cosmology and astronomy,  microprocessor research and design, large-scale data mining and so on.
Supercomputers use parallel processing architectures of interconnected  microprocessors (which can execute many instructions at the same time in  parallel). They can perform arithmetic calculations at speeds of  billions of floating-point operations per second (gigaflops). Teraflop  (1 trillion floating-point operations per second) supercomputers, which  use advanced massively parallel processing (MPP) designs of thousands of  interconnected microprocessors, are becoming available. Purchase prices  for large supercomputers are in the $5 million to $50 million range.
However, the use of symmetric multiprocessing (SMP) and distributed  shared memory (DSM) designs of smaller numbers of interconnected  microprocessors has spawned a breed of minisuper computers with prices  that start in the hundreds of thousands of dollars.
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Monday, July 16, 2012
Sunday, July 1, 2012
IBPS Probationary Officers' Exam 2011
Computer Knowledge
(Exam Held On: 18-09-2011)
1. Computer uses the_________number system to store data and perform calculations.
(A) binary(B) octal
(C) decimal
(D) hexadecimal
(E) None of these
Ans : (A)
2. A disk's content that is recorded at the time of manufacture and that cannot be changed or erased by the user is_______________
(A) Memory-only(B) Write-only
(C) Once-only
(D) Run-only
(E) Read-only
Ans : (E)
3. Which of the following can be used to select the entire document ?
(A) CTRL+A(B) ALT+F5
(C) SHIFT+A
(D) CTRL+K
(E) CTRL+H
Ans : (A)
4___________are 'attempts by individuals to obtain confidential information from you by falsifying their identity.
(A) Phishing(B) Computer viruses
(C) Spyware scams
(D) Viruses
(E) None of the above
Ans : (A)
5. Part number, part description, and number of parts ordered are examples of__________
(A) control(B) output
(C) processing
(D) feedback
(E) input
Ans : (E)
6. A Web site's main page is called its______________
(A) Home Page(B) Browser Page
(C) Search Page
(D) Bookmark
(E) None of these
Ans : (A)
7. The simultaneous processing of two or more programs by multiple processors is_____________
(A) multiprogramming(B) multitasking
(C) time-sharing
(D) multiprocessing
(E) None of these
Ans : (D)
8. Codes consisting of lines of varying widths or lengths that are computer-readable are known as____________
(A) an ASCII code(B) a magnetic tape
(C) an OCR scanner
(D) a bar code
(E) None of these
Ans : (D)
9. To instruct Word to fit the width of a column to the contents of a table automatically, click the button and then point to AutoFit Contents.
(A) Fit to Form(B) Format
(C) Autosize
(D) Contents
(E) AutoFit
Ans : (E)
10. Why is it unethical to share copyrighted files with your friends ?
(A) It is not unethical, because it is legal.(B) It is unethical because the files are being given for free.
(C) Sharing copyrighted files without permission breaks copyright laws.
(D) It is not unethical because the files are being given for free.
(E) It is not unethical-anyone can access a computer
Ans : (C)
11. Reusable optical storage will typica1ly have the acronym__________
(A) CO(B) DVD
(C) ROM
(D) RW
(E) ROS
Ans : (D)
12. The most common type of storage devices are__________
(A) persistent(B) optical
(C) magnetic
(D) flash
(E) steel
Ans : (D)
13. A device that connects to a network without the use of cables is said to be_________
(A) distributed(B) free
(C) centralized
(D) open source
(E) None of these
Ans : (B)
14. A person who used his or her expertise to gain access to other people's computers to get information illegally or do damage is a______________
(A) hacker(B) analyst
(C) instant messenger
(D) programmer
(E) spammer
Ans : (A)
15. To access properties of an object, the mouse technique to use is__________________
(A) dragging(B) dropping
(C) right-clicking
(D) shift-clicking
(E) None of these
Ans : (C)
16. To change selected text to all capital letters, click the change case button, then click___________
(A) UPPERCASE(B) UPPER ALL
(C) CAPS LOCK
(D) Lock Upper
(E) Large Size
Ans : (A)
17. The basic unit of a worksheet into which you enter data in Excel is called a______________
(A) tab(B) cell
(C) box
(D) range
(E) None of these
Ans : (B)
18. You can keep your personal files / folders in____________________
(A) My folder(B) My Documents
(C) My Files
(D) My Text
(E) None of these
Ans : (B)
19. In Word you can force a page break____________
(A) By positioning your cursor at the appropriate place and pressing the F1 key(B) By positioning your cursor at the appropriate place and pressing Ctrl+Enter
(C) By using the Insert/Section Break
(D) By changing the font size of your document
(E) None of these
Ans : (B)
20. A DVD is an example of a(n) ______________
(A) hard disk(B) optical disc
(C) output device
(D) solid-state storage device
(E) None of these
Ans : (B)
21. The default view in Excel is___________view.
(A) Work(B) Auto
(C) Normal
(D) Roman
(E) None of these
Ans : (C)
22. The process of transferring files from a computer on the Internet to your computer is called___________
(A) downloading(B) uploading
(C) FTP
(D) JPEC
(E) downsizing
Ans : (A)
23.____________.is the process of dividing the disk into tracks and sectors.
(A) Tracking(B) Formatting
(C) Crashing
(D) Allotting
(E) None of these
Ans : (B)
24. Help Menu is available at which button ?
(A) End(B) Staft
(C) Turnoff
(D) Restart
(E) Reboot
Ans : (B)
25. The contents of____________are lost when the computer turns off.
(A) storage(B) input
(C) output
(D) memory
(E) None of these
Ans : (D)
26. When you save to this, your data will remain intact even when the computer is turned off________
(A) RAM(B) Motherboard
(C) Secondary storage device
(D) Primary storage device
(E) None of these
Ans : (C)
27. A central computer that holds collections of data and programs for many PCs, workstations, and other computers is a(n)_________
(A) supercomputer(B) minicomputer
(C) laptop
(D) server
(E) None of these
Ans : (D)
28. The_________folder retains copies of messages that you have started but are not yet ready to send.
(A) Drafts(B) Outbox
(C) Address Book
(D) Sent Items
(E) Inbox
Ans : (B)
29. Grouping and processing all of a firm's transactions at one time is called_________
(A) a database management system(B) batch processing
(C) a real-time system
(D) an on-line system
(E) None of these
Ans : (B)
30. The___________enables you to simultaneously keep multiple Web pages open in one browser window.
(A) tab box(B) pop-up helper
(C) tab row
(D) address bar
(E) Esc key
Ans : (C)
31. Which ports connect special types of music instruments to sound cards ?
(A) BUS(B) CPU
(C) USB
(D) MIDI
(E) MINI
Ans : (C)
32. You can__________a search by providing more information the search engine can use to select a smaller, more useful set of results.
(A) refine(B) expand
(C) load
(D) query
(E) slowdown
Ans : (A)
33. What is the permanent memory built into your computer called ?
(A) RAM(B) Floppy
(C) CPU
(D) CO-ROM
(E) ROM
Ans : (E)
34. What displays the contents of the active cell in Excel ?
(A) Name box(B) Row Headings
(C) Formula bar
(D) Task pane
(E) None of these
Ans : (A)
35. The piece of hardware that converts your computer's digital signal to an analog signal that can travel over telephone lines is called a_______
(A) red wire(B) blue cord
(C) tower
(D) modem
(E) None of these
Ans : (D)
36. Video processors consist of________and________, which store and process images.
(A) CPU and VGA(B) CPU and memory
(C) VGA and memory
(D) VGI and DVI
(E) None of these
Ans : (C)
37. If you want to connect to your own computer through the Internet from another location, you can use_________
(A) e-mail(B) FTP
(C) instant message
(D) Telnet
(E) None of these
Ans : (D)
38. To reload a Web page, press the___________.button.
(A) Redo(B) Reload
(C) Restore
(D) Ctrl
(E) Refresh
Ans : (E)
39. This first step in the transaction processing cycle captures business data through various modes such as optical scanning or at an electronic commerce website__________
(A) Document and report generation(B) Database maintenance
(C) Transaction processing startup
(D) Data Entry
(E) None of these
Ans : (D)
40. A(n)_____________is a special visual and audio effect applied in Power-point to text or content.
(A) animation(B) flash
(C) wipe
(D) dissolve
(E) None of these
Ans : (A)
41. When the pointer is positioned on a__________it is shaped like a hand.
(A) grammar error(B) Formatting error
(C) Screen Tip
(D) Spelling error
(E) hyperlink
Ans : (E)
42. Personal computers can be connected together to form a__________
(A) server(B) supercomputer
(C) network
(D) enterprise
(E) None of these
Ans : (C)
43. A______________is the term used when a search engine returns a Web page that matches the search criteria.
(A) blog(B) hit
(C) link
(D) view
(E) success
Ans : (E)
44. ___________are words that a programming language has set aside for its own use.
(A) Control words(B) Control structures
(C) Reserved words
(D) Reserved keys
(E) None of these
Ans : (C)
45. Mobile Commerce is best described as___________
(A) The use of Kiosks in marketing(B) Transporting products
(C) Buying and selling goods/services through wireless handheld devices
(D) Using notebook PC's in marketing
(E) None of the above
Ans : (C)
46. Which of, the following is a storage device that uses rigid, permanently installed magnetic disks to store data/information__________
(A) floppy diskette(B) hard disk
(C) permanent disk
(D) optical disk
(E) None of these
Ans : (B)
47. The computer abbreviation KB usually means___________
(A) Key Block(B) Kernel Boot
(C) Key Byte
(D) Kit Bit
(E) Kilo Byte
Ans : (E)
48. What is the process of copying software programs from secondary storage media to the hard disk called?
(A) Configuration(B) Download
(C) Storage
(D) Upload
(E) Installation
Ans : (D)
49. In Excel____________allows users to bring together copies of work-books that other users have worked on independently.
(A) Copying(B) Merging
(C) Pasting
(D) Compiling
(E) None of these
Ans : (B)
50. Which of the following are advantages of CD-ROM as a storage media?
(A) CD-ROM is an inexpensive way to store large, amount of data and information(B) CD-ROM disks retrieve data and information more quickly than magnetic disks do
(C) CD-ROMs make less errors than magnetic media
(D) An of the above
(E) None of these
Ans : (D)
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