Current Affairs 4th Class

      Introduction   You may have used the computer to store games, music files and pictures in it. These files get stored in the memory devices. A memory device is a device that preserves information (data and instructions) for retrieval in the future. Every computer uses storage to hold software such as system software and application software. To boot up, a computer locates an operating system (system software) in the storage and loads it into memory. When users issue commands to start application software, such as word processing, the operating system locates the program in storage and loads it into memory. In this chapter, we will learn about some characteristics of memory devices.

      Secondary Memory Devices     All computers store and retrieve data. Since primary memory has a limited storage capacity and is not permanent, secondary storage devices are used to store large amount of data permanently. Secondary memory devices are external devices and stores data for the future. Secondary memory devices include magnetic disks like hard drives and floppy disks, optical disks such as CDs and CD-ROM and magnetic tapes, which were the first forms of secondary memory. Secondary memory (or secondary storage) is the slowest and cheapest form of memory. It cannot be processed directly by the CPU. It must first be copied into primary memory (also known as RAM). Secondary storage (or external memory) differs from primary storage because they are not directly accessible by the CPU. The computer usually uses its input/ output channels to access secondary storage and then transfers the desired data using an Intermediate area in primary storage.                     Secondary storage does not lose the data even when the power goes off?it is non-volatile. (See Figure 4,2.6) In modern computers, hard disk drives are usually used as secondary storage. The time taken to access a given byte of information stored on a hard disk is typically a few thousandths of a second or milliseconds. By contrast, the time taken to access a given byte of information stored in random access memory is measured in billionths of a second or nanoseconds. Some other examples of secondary storage technologies are: flash memory (e.g. USB flash drives or keys), paper tape, punched cards, standalone RAM disks and Iomega Zip drives. (See Figure 4.2.7)                     COMPUTER MEMORIES                      Fill in the blanks: 1. Secondary memory devices are ___ devices and stores data for the __ . 2. Secondary memory is not directly accessible by the ______ . 3. Secondary memory is the _________   and cheapest form of memory. (A) Internal, Present, Modem, Fastest (B) External, Future, CPU, Slowest (C) External, Present, Modem, medium (D) Internal, Future, CPU, Slowest (E) External, Present, Hard disk, Slowest     Answer: (b) Explanation Correct Option: (B) Options given in (B) are correct. Incorrect Options: (A) Options given in (A) are incorrect. Therefore, option (A) is incorrect. (C) Options given in (C) are incorrect. Therefore, option (C) is incorrect. (D) Options given in (D) are incorrect. Therefore, option (D) is incorrect. (E) Options given in (E) are incorrect. Therefore, option (E) is incorrect.        Given below are the statements about secondary memory. Select the correct statement. 1. Flash memory, paper tape and punched cards are the examples of secondary memory. more...

        Primary Memory or Main Memory                 Types of Main Memory:

• All computers have main or primary memory to store programs and data .while the computer is running.
• The main memory has 2 subtypes:RAM (Random Access Memory) and ROM (Read-only Memory).

      RAM (Random Access Memory) and ROM (Read-only Memory).     RAM (Random Access Memory)  RAM can be compared to a person's short-term memory and the hard disk to the long-term memory. The short-term memory focuses on work at hand, and can keep only a few facts in view at one time. If short-term memory fills up, your brain is sometimes able to refresh it from facts stored in long-term memory. A computer also works this way. If RAM fills up, the processor needs to continually go to the hard disk to overlay old data in RAM with new, slowing down the computer's operation. RAM is the internal memory that can be read. When people talk about computer memory, they are generally referring to the RAM. RAM is volatile i.e. its contents are lost when power is turned off. RAM also has a limited storage capacity. RAM (random access memory) is the place in a computer where the operating system, application programs and data in current use are kept so that they can be quickly reached by the computer's processor. RAM is much faster to read than the other kinds of storage in a computer such as the hard disk, floppy disk and CD-ROM. However, the data in RAM stays there only as long as your computer is running. When you turn the computer off, RAM loses its data. When you turn your computer on again, your operating system and other files are once again loaded into RAM, usually from your hard disk. RAM is a type of computer memory that can be accessed randomly; that is, any byte of memory can be accessed without touching the preceding bytes. RAM is the most common type of memory found in computers and other devices, such as printers. There are two different types of RAM: DRAM (Dynamic Random Access Memory) and SRAM (Static Random Access Memory). The two types differ in the technology they use to hold data. In common usage, the term RAM refers to the main memory or the memory available to the programs. For example, a computer with 8MB RAM has approximately 8 million bytes of memory that programs can use.         ROM (Read-only memory) In this memory, information once stored remains fixed i.e. it cannot be changed. Severally, ROM contains a set of Start-up instructions, that is, what to do when a computer is turned on. The contents of ROM remain stored even if power is turned off; hence it is more...

  Introduction     You can remember things because they are stored in your memory (brain). Similarly, a computer has memory to store data and information for future use. The Memory's the computer's work area. This is the place where the data and programs get stored before being processed and the place where the results get stored before being sent as output. Suppose you are asked when your birthday is or the name of your friends, you will reply immediately because you 'member them and this information s already in your memory. A computer also has a memory which stores a lot of information inside it. A computer stores everything in its memory. All the data that enters into the computers first get converted into the binary number system. One digit in binary number system is called bit and combination of eight:  is called byte. Bit is the smallest measuring unit of computer memory. It means binary digits. Just like we use kilograms and grams to measure weight, the computer's memory is organized as a collection of bytes.         Units to measure memory are given in the following table: Bit = 0 or 1 Nibble = 4 Bits 1 Byte (B) = 8 Bits 1 Kilobyte (KB) = 1024 B 1 Megabyte (MB) = 1024 KB 1 Gigabyte (GB) = 1024 MBS

         Scanner     A scanner creates an electronic form of the printed image which can then be manipulated, changed and modified according to the requirements. The scanners can convert any image and printed text into electronic form by shining light on to the image and sensing the intensity of the reflection at every point. The resolution of a scanner is a measure of the number of pixels it uses. Higher resolution means clearer pictures. Scanners come in 2 different models - Hand-held Scanner and Flatbed Scanner           Hand-held Scanner     Hand-held scanner is a small handheld scanning device used for digitizing images. While images from a handheld scanner are considered low quality, today's technology enables full colour24 bit scanning. Depending on the scanner device type and manufacturer, handheld scanners can also define, translate and hear printed text, and can also store and beam text to computers and other devices. Hand scanners come in two forms: document and 3D scanners. Hand-held document scanners are manual devices that are dragged across the surface of the image be scanned. Hand-held Scanners are very small which can be held in a land. These are less expensive but less wide. Multiple o asses are required to scan a single page image, but their handiness is a big advantage.              Flatbed Scanner     Flatbed scanners are a type of optical scanner that consist of a flat surface on which you lay documents to be scanned. Flatbed scanners are particularly effective for bound documents. Flatbed scanners are larger and more expensive scanners and create higher quality images. These scanners have a flat surface on which the printed image to be scanned is placed. Flatbed scanners can scan a page in a single pass. Flatbed scanners are very accurate and can produce images with a far higher resolution than a digital camera.                                                              Information about the scanner is given below. Select the correct one. 1. A scanner creates an electronic form of the printed image which can then be manipulated, changed and modified according to the requirements. 2. The scanners can convert specific images into electronic form by shining light on to the image and sensing the intensity of the reflection at every point. 3. Scanners come in 4 different models. (A) 1 and 2                                                          (B) 1 and 3 (C) Only 1                                                            (D) All of these (E) None of these   Answer: (C) Explanations Correct Option: (C) Only statement 1 is correct about scanners. Incorrect Options: (A) Statement 1 is correct but statement 2 is incorrect. Therefore, option (A) is incorrect. (B) Statement 1 is correct but statement 3 more...

      Speakers     The speakers that are attached to the computer are similar to the ones that are connected to a stereo. The computer system's speakers are smaller and they contain their own small amplifier. Speakers receive the sound in the form of electric current from the sound card and then convert it into sound format. Computer speakers range widely in quality and in price. The computer speakers typically packaged with computer systems are small plastic boxes with mediocre sound quality. Some of the slightly better computer speakers have equalization features such as bass and treble controls which improves their sound quality. The internal amplifiers require an external power source, known as a 'wall-wart'. Laptops come with integrated speakers.               Havel and Mori are discussing about speaker. Read their statements and identify the correct one. Havel: The speakers attached to the computer are similar to the ones that are connected to a stereo. The computer system's speakers are smaller and they contain their own small amplifier. Mori: Ok, computer's speakers has their own amplifier but speakers receive the sound in the form of long reel from the sound card and then convert it into sound format. (A) Havel is correct                                          (B) Mori is correct (C) Both are partially correct                       (D) Both are correct (E) None of them are correct     Answer: (a) Explanation Correct Option: (A) The information given by Havel about speaker is correct. Incorrect Options: (B) The information given by Mori about speaker is incorrect. Therefore, option (B) is incorrect. (C) Havel is fully correct and Mori is fully incorrect. Therefore, option (C) is incorrect. (D) Both of them are not correct. Only Havel is correct. Therefore, option (D) is incorrect. (E) Both of them are not incorrect. Only Mori is incorrect. Therefore, option (E) is incorrect.          Few statements are given below about speakers. Complete the given statements with correct words. 1. The internal amplifiers require an external power source known as a 2. _______ and _______ controls, improves speakers sound quality. 3. Laptops come with _________ speakers. (A) Wall-nut, Bass, Treble, Digital (B) Wall-wart, Bass, Treble, Analog (C) Wall-wart, bass, treble, Integrated (D) Nut-bolt, Boss, treble, Analog (E) Wall-bolt, box, treble. Integrated     Answer: (c) Explanation Correct Option: (C) Options given in (C) are correct. Incorrect Options: (A) Options given in (A) are incorrect. Therefore, option (A) is incorrect. (B) Options given in (B) are incorrect. Therefore, option (B) is incorrect. (D) Options given in (D) are incorrect. Therefore, option (D) is incorrect. (E) Options given in (E) are incorrect. Therefore, option (E) is incorrect.  

         Modem     A modem is a device attached to the computers that can convert digital signals to analog signal and vice- versa. Digital signal is a group of discrete electronic units that are transmitted in rapid succession and an analog signal consists of continuous electrical waves. Modem is a short name for modulator-demodulator, where modulator can convert digital signals to analog signals and demodulator does the opposite. Modem is a device that enables computers, fax machines and other equipment to communicate with each other across telephone lines or over cable television network cables. Since telephone cables can carry analog signals, the computer generated digital signal is first converted into analog form so that it can be carried by telephone lines. Upon receiving it, the modem at receiver end can understand it. Modems transmit data at different speeds, measured by the number of bits of data they send per second (bps). Examples of modem speeds are: 256 Kbps, 512 Kbps, 2mbps, etc.                Given below are the statements about MODEM. Select the correct statements. 1. A modem is a device attached to the computers that can convert analog signal to digital signals and vice-versa. 2. An analog signal is a group of discrete electronic units that are transmitted in rapid succession. 3. Digital signal consists of continuous electrical waves. (A) Only 1                                                            (B) 2 and 3 (C) 1 and 3                                           (D) All of these (E) None of these.     Answer: (a) Explanation Correct Option: (A) Only statement 1 is correct about MODEM. Incorrect Options: (B) Statements 2 and 3 are incorrect about MODEM. Therefore, option (B) is incorrect, (C) Statement 1 is correct but statement 3 is incorrect. Therefore, option (C) is incorrect. (D) All the given statements are not correct. Therefore, option (D) is incorrect. (E) All the given statements are not incorrect. Therefore, option (E) is incorrect.          Fill in the blanks: 1. Modulator can convert ____ signals to ____ signals. 2. Demodulator convert ____ signals to ____ signals. 3. Modems transmit data at different speeds, which are measured in ______. (A) Analog, Digital, Digital, Analog, Bit per second (B) Digital, Analog, Digital, Analog, Byte per second (C) Digital, Analog, Analog, Digital, Bit per second (D) Digital, Analog, Digital, Analog, Bit per minutes (E) Digital, Analog, Analog, Digital, Data per second   Answer: (c) Explanation Correct Option: (C) Options given in (C) are correct. Incorrect Options: (A) Options given in (A) are incorrect. Therefore, option (A) is incorrect. (B) Options given in (B) are incorrect. Therefore, option (B) is incorrect. (D) Options given in (D) are incorrect. Therefore, option (D) is incorrect. (E) Options given in (E) are incorrect. Therefore, option (E) is incorrect.

        Microphone       You can send sound or audio input to the computer through a special input device called microphone. A microphone converts the sound received into the computer's format, which is called digitized sound or digital audio. A microphone can work only if your computer has a special hardware known as sound card. Sound is more often used in multimedia where there is recorded narration, music or sound effects. A microphone is a hardware peripheral that is a popular solution for computer gaming.   In 1876, Emile Berliner invented the first microphone used as a telephone voice transmitter. Microphones are used in many applications such as telephones, tape recorders, karaoke systems, hearing aids, motion picture production, live and recorded audio engineering, megaphones, in radio and television broadcasting and in computers for recording voice and speech recognition. Richard and Morton have giving their comment on Microphone.              Read their comments and identify who is correct. Richard: Emile Berliner invented the first microphone used as a telephone voice transmitter in the year 1876. Morton: A microphone is a hardware peripheral that is a popular solution for computer gaming. (A) Richard is correct                                                      (B) Morton is correct (C) Both are partially correct                                       (D) Both are correct (E) None of them are correct   Answer: (D) Explanation Correct Option: (D) The comments given by Richard and Morton are correct. Incorrect Options: (A) Not only Richard is correct but Morton is also correct. Therefore, option (A) is incorrect. (B) Not only Morton is correct but Richard is also correct; Therefore, option (A) is incorrect. (C) Both of them are fully correct. Therefore, option (C) is incorrect. (E) Both of them are correct. Therefore, option (E) is incorrect.            Fill in the blanks: 1. You can send sound to the computer through a special input device called_________. 2. A microphone converts the sound received into_________. 3. A microphone can work only if your computer has a special hardware known as _______. (A) Microphone, Analog, Video card       (B) Monophony, Digitized, Audio card (C) Microphone, Digitized, Sound card   (D) Cordless phon,. Analog, Sound card (E) Microphone, Analog, Sound card     Answer: (D) Correct Option: (E) Options given in (E) are correct. Incorrect Options: (A) Options given in (A) are incorrect. Therefore, option (A) is incorrect. (B) Options given in (B) are incorrect. Therefore, option (B) is incorrect. (C) Options given in (C) are incorrect. Therefore, option (C) is incorrect. (D) Options given in (D) are incorrect. Therefore, option (E) is incorrect.  

       CD-ROM     You must have seen or used CDs for watching movies, playing games and listening to music. CD-ROM is an acronym of "Compact Disc Read-Only Memory". It is a type of optical disk capable of storing large amounts of information. Users use CD-ROMs to record information including text, graphics or audio on the CD, CD-ROMs are stamped by the vendor and once stamped; they cannot be erased and filled with new data. To read a CD, you need a CD-ROM player. CD-ROMs are particularly well-suited for information that requires large storage capacity. This includes large software applications that support colour, graphics, sound and especially video.              Given below is the information about CD-ROM. Select the correct statements. 1. CD-ROM is an acronym of "Composite Drive Read-Only Memory" 2. CD-ROM is a type of optical disk capable of storing large amounts of information. 3. CD-ROMs are stamped by the client and once stamped; it cannot be erased and filled with new data. (A) 1 and 3                                                          (B) Only 2 (C) 1 and 2                                                           (D) All of these (E) None of these     Answer: (b) Explanation Correct Option: (B) Only statement 2 is correct about CD-ROM. Incorrect Options: (A) Statements 1 and 3 are incorrect. Therefore, option (A) is incorrect, (C) Statement 1 is incorrect and statement 2 is correct. Therefore, option (C) is incorrect. (D) All the given statements are not correct. Thereto option (D) is incorrect. (E) All the given statements are not incorrect. Therefore, option (E) is incorrect.          Fill in the blanks: 1. To read a CD, you need a CD-ROM player 2. Manufacturers use CD-ROMs to record information that includes text,________ or________ on the CD distribution. 3. CD-ROMs are particularly well-suited for information that requires ______ capacity.   (A) DVD player, Graphics, Audio, Small storage (B) LCD player, numbers, video, medium storage (C) CD-ROM player, Graphics, Audio, Large storage (D) CD-ROM player. Fonts, Format, Large storage (E) DVD player. Graphics, Audio, Large storage     Answer: (c) Explanation Correct Option: (C) Options given in (C) are correct. Incorrect Options: (A) Options given in (A) are incorrect. Therefore, option (A) is incorrect. (B) Options given in (B) are incorrect. Therefore, option (B) is incorrect. (D) Options given in (D) are incorrect. Therefore, option (D) is incorrect. (E) Options given in (E) are incorrect. Therefore, option (E) is incorrect.  

     Printer     Printers are output devices used to produce printed papers from the computer, Printers can produce text and images on paper and this is called 'hard copy'. Based on the technology used, they can be classified as Impact or Non-impact printers. Impact printers use the typewriting printing mechanism where there is a mechanical contact between the print head and paper. Dot-matrix and Character printers fall under this category. Non-impact printers do not touch the paper while printing. They use chemical, heat or electrical signals to etch the symbols on paper. Inkjet, DeskJet, Laser and Thermal printers fall under this category of printers. Printers are generally slow devices (30 pages per minute are considered fast) and the cost per page is actually relatively high.            Robson and Alan are discussing on the topic 'Printer'. Read their conversation and identify who is correct. Robson: Printer is an output device and used to produce paper copies of output from the computer. Printers can produce text and images on paper and this is called 'hard copy'. Alan: Now a days we see different types of printer in the market and laser printer is common among them. (A) Robson is correct                                                      (B) Alan is correct (C) Both are correct                                                        (D) Both are correct (E) None of these     Answer: (D) Explanation Correct Option: (D) The information given by Robson and Alan is correct. Incorrect Options: (A) Information given by Robson is correct. Therefore, option (A) is incorrect. (B) Information given by Alan is correct. Therefore, option (B) is incorrect. (C) Both of them are correct. Therefore, option (C) is incorrect.        Match the following:         A                                                             B 1. Impact printer                                        i. Thermal printers                                                                     ii. Character printer 2. Non-impact printer                               iii. Laser printer                                                                     iv. Dot-matrix printer (A) 1 - iii, iv; 2 - i, ii                                            (B) 1 - ii, iii; 2 - i, iv (C) 1 - ii, iv; 2 - i, iii                                             (D) 1 - ii; 2 - i, iii, iv   (E) 1 - ii, iii, iv; 2 - i     Answer: (c) Explanation Correct Option: (C) Option (C) is matched correctly. Incorrect Options: (A) Option (A) is matched more...