Computer Awareness Mixed Quiz: Set 13

The correct answer is B, Windows operating system. System software is the software that runs the machine itself. It manages the processor, the memory, the disk and the attached devices, and it gives other programs a platform on which to run. An operating system such as Windows, Linux or Android is the leading example of it; device drivers, utilities like antivirus and disk cleaners, and language translators such as compilers and assemblers are the others. Application software is written instead for a job the user wants done, and it cannot run at all unless system software is already working underneath it. A is wrong because Adobe Photoshop is an application for editing images. C is wrong because Google Chrome is an application, a web browser. D is wrong because Microsoft Word is an application for word processing. Exam tip: system software runs the computer, so operating systems, drivers, utilities and compilers; application software does the user's work, so Word, Chrome and Photoshop.

The correct answer is A, Program counter. In the 8085A microprocessor the program counter is a 16-bit register that always holds the memory address of the next instruction, or op-code, to be fetched. After each fetch it is incremented automatically, and a jump or call instruction loads a new address into it so that control moves elsewhere in the program. Two other registers of the 8085 are often confused with it. The accumulator is the 8-bit register A in which arithmetic and logic results are stored. The stack pointer is a 16-bit register holding the address of the top of the stack, used while saving return addresses and register contents. B and C are wrong for those reasons. D is wrong because instruction pointer is the name Intel's later x86 processors use for the same idea; the 8085 register is called the program counter. Exam tip: 8085 has an 8-bit accumulator and 16-bit program counter and stack pointer.

The correct answer is C, FTP. FTP stands for File Transfer Protocol. It opens two channels with a server, one on port 21 for commands and one on port 20 for the matter itself, and moves whole files in either direction, which is how web pages are put on a hosting server.

Option A, SMTP, carries outgoing email and can send a file only as an attachment to a letter, not as a plain transfer. Option B, Telnet, lets a user log in to a distant computer and type commands on it through port 23; it gives control of the machine but does not itself move files. Option D, IMAP, is a mail-reading protocol that keeps letters on the server. For pure file transfer the answer is always FTP, or its secure forms FTPS and SFTP.

The correct answer is C, Extended Binary Coded Decimal Interchange Code. EBCDIC is an 8-bit character encoding scheme developed by IBM in 1963 for its mainframe and midrange computers. Because it uses 8 bits for each character it can represent 256 different characters, twice as many as the 7-bit ASCII code, which handles 128. EBCDIC grew out of the older Binary Coded Decimal system and is still found on IBM mainframes, while ASCII became the standard for personal computers and Unicode now covers the scripts of the world, including Devanagari. A is wrong because the third word is Coded, not Control. B is wrong on two counts: the first word is Extended and the third is Coded. D is wrong because the expansion ends with Decimal Interchange Code, not Data Integration Code. Exam tip: EBCDIC is 8-bit and 256 characters, ASCII is 7-bit and 128 characters, Unicode is 16-bit and covers all scripts.

The correct answer is A, Attack Surface. The attack surface of a system is the total collection of every point at which an unauthorised person could try to enter it or pull data out of it: open ports, running services, user accounts, login pages, removable drives and even the employees who can be tricked. Network administrators reduce risk by shrinking this surface, that is by closing unused ports and removing software that is not needed. Option B is wrong because an attack signature is the recognisable pattern of bytes or behaviour by which antivirus and intrusion detection software identify a known attack. Option C is wrong because an attack pattern is a general description of how a class of attacks is carried out, used while designing defences. Option D is wrong because an attack path, also called an attack vector chain, is the particular route a single intruder actually followed from entry to target, not the whole set of possible entry points.

The correct answer is D, Transmission speed. The 56 K rating of a modem means it can transfer data at up to 56 kilobits per second, so the figure describes speed, not size. A modem, short for modulator-demodulator, converts the computer's digital signals into analogue form for a telephone line and converts incoming analogue signals back into digital form. Data transfer speed is measured in bits per second and its multiples, kbps, Mbps and Gbps, and the 56 kbps dial-up modem was the fastest standard for ordinary telephone lines before broadband. A is wrong because the physical size of a modem is not rated in kilobits. B is wrong because memory size is measured in bytes such as MB or GB, not in K of this kind. C is wrong because capacity here is loosely worded; the rating fixes the rate of transfer per second. Exam tip: modem speed is in bits per second; storage is in bytes.

The correct answer is D, E. Hexadecimal has base 16, and because 2 raised to the power 4 equals 16, exactly four binary bits make one hexadecimal digit. The given number 1110 is already a group of four bits, so it converts in one step. Its place values are 8, 4, 2 and 1, and the bits are 1, 1, 1 and 0, so the decimal value is 8 + 4 + 2 + 0, that is 14. In hexadecimal the decimal values 10 to 15 are written as the letters A to F, so 10 is A, 11 is B, 12 is C, 13 is D, 14 is E and 15 is F. Fourteen is therefore E. Option A is wrong because F stands for 15, whose binary form is 1111. Option B is wrong because B stands for 11, that is 1011. Option C is wrong because A stands for 10, that is 1010.

The correct answer is D, the operating system will return an error indicating that the directory is not empty. The plain remove-directory command is built to delete an empty folder only. In Windows it is rmdir, also written rd, and in Linux it is rmdir; both stop with a message such as "The directory is not empty" when anything is still inside. To remove a folder along with everything in it you have to ask for it: rmdir /s in Windows or rm -r in Linux, which walks through the tree, deletes the contents and then the folder. This guard exists so that a single short command cannot wipe out a large tree by mistake. Option A is wrong because nothing inside is touched without the recursive switch. Option B is wrong because a file system cannot leave files with no parent folder; the entries go together or not at all. Option C is wrong because the plain command does not ask item by item, which is what an interactive option like rm -i does. Exam tip: rmdir empties only, rm -r for the whole tree.

The correct answer is B, Datasheet. In a database such as Microsoft Access, the view that shows a table as rows and columns, looking like a spreadsheet grid, is called Datasheet view. Each row of that grid is one record and each column is one field, and the names along the top come from the field names set in Design view. Datasheet view lets you type data straight in, sort it, filter it and widen columns, while Design view is where the data type, field size and primary key are fixed. Queries and forms can also be opened in Datasheet view, so the name belongs to the display format, not to one object. Option A is wrong because a record is a single row of the grid, one complete entry, not the grid itself. Option C is wrong because a query is a saved question that pulls out selected rows; it is a database object. Option D is wrong because 'Tables' names the objects being displayed, while the question asks what the grid-like view is called. Exam tip: Access tables have two main views — Datasheet for data, Design for structure.

The correct answer is B, Drupal. Drupal is a content management system, a free program used to build and run websites; it keeps its pages in a database but is not itself a database management system. A DBMS is the software layer that creates, stores, queries and secures data, and the other three names are all DBMS products. Option A, Oracle, is the commercial relational database widely used by banks and large businesses. Option C, MySQL, is the open source relational database that a large share of the web runs on; Drupal and WordPress in fact store their content in a MySQL database, which shows the difference between the two kinds of software. Option D, MS Access, is the small desktop database that ships with Microsoft Office and keeps tables, queries, forms and reports in a single file. Exam tip: Oracle, MySQL, MS Access, SQL Server and PostgreSQL are database managers; Drupal, Joomla and WordPress are content management systems.

The correct answer is C, Netscape. Netscape Navigator, released in 1994 by Netscape Communications, the company founded by Marc Andreessen and Jim Clark, was the first web browser sold as a commercial product. It was the browser that carried the web to ordinary users in the mid nineties and at its peak held most of the market, before losing the browser war to Internet Explorer. A is wrong because Mosaic, built in 1993 at the NCSA of the University of Illinois, was the first widely used graphical browser but was academic software given away free, not a commercial product. B is wrong because Mozilla is the open source project born in 1998 from Netscape's released source code; its browser Firefox came in 2004 and is free. D is wrong because Internet Explorer arrived in 1995 and was bundled free with Windows rather than sold. Exam tip: Mosaic 1993 first popular graphical browser, Netscape Navigator 1994 first commercial browser, Firefox 2004 from the Mozilla project.

The correct answer is D, All of the above. A high-level language is written in words close to English and has to be turned into machine code by a compiler or an interpreter, so the programmer need not know the processor at all. All three named languages are of this kind. COBOL, from 1959, was built for business data processing and Grace Hopper was central to its design. PASCAL, designed by Niklaus Wirth around 1970 and named after Blaise Pascal, was made for teaching structured programming. BASIC, written by Kemeny and Kurtz in 1964, was the beginners language of early home computers. Options A, B and C are each individually correct but incomplete, and the question asks for the choice that covers every high-level language listed, so the fuller option D is the right one. Exam tip: machine and assembly language are low level, C, COBOL, BASIC, PASCAL, FORTRAN and Java are high level.

The correct answer is C, Graphics. In multimedia, graphics is the broad word for every kind of visual element a computer can store and show, so drawings, photographs, movies and simulations all sit inside it. The usual list of multimedia elements is text, graphics, audio, video and animation, and in that list graphics covers both pictures made by hand on the screen and pictures captured from the real world. Graphics are stored either as bitmaps, made of pixels, as in a JPEG or BMP photograph, or as vectors, made of lines and curves described by equations, as in a drawing or a CAD file. A is wrong because animation is only one kind of visual, a sequence of frames shown fast enough to look like movement. B is wrong because an image is a single still picture, so it is narrower than the four things listed. D is wrong because text is made of characters and carries no picture. Exam tip: multimedia elements are text, graphics, audio, video and animation; bitmap graphics use pixels, vector graphics use equations.

The correct answer is D, Virtualization. Virtualization creates a software layer over the physical processor, memory and storage of a machine, so that one server can be divided into several virtual machines, each running its own operating system as though it had hardware of its own. The program that makes this possible is the hypervisor. Because a single strong server then does the work of many lightly used ones, organisations buy less hardware and spend less on power, cooling and floor space, which is why it is called the most effective way to cut IT costs. It is also the base on which cloud computing is built. Option A is wrong because artificial intelligence is about machines doing tasks that need human-like reasoning. Option B is wrong because clustering joins several computers to work as one for speed and reliability, not to abstract resources. Option C is wrong because a storage area network is a dedicated network for storage alone. Exam tip: hypervisor runs virtual machines, and virtualization underlies cloud computing.

The correct answer is C, Joint Photographic Experts Group. The format is named after the committee of experts that drew up the standard, which was published in 1992 for compressing photographs. A JPEG file uses lossy compression: it throws away the fine detail the human eye is least likely to miss, so a picture that would need several megabytes as raw data is stored in a few hundred kilobytes. That is why photographs on websites and in phone galleries are saved as .jpg or .jpeg, while logos, line drawings and screenshots are better kept as PNG or GIF, which are lossless. A is wrong because it puts Photography and Exports in place of Photographic and Experts. B is wrong because it replaces Photographic with Pixel. D is wrong on both counts, using Pixel as well as Exports. Exam tip: JPEG is the Joint Photographic Experts Group and is lossy; PNG and GIF are lossless; MPEG is the Moving Picture Experts Group.

The correct answer is A, 32. An IPv4 address, which is what the question means by an IP address, is thirty-two bits long. It is written in dotted-decimal form as four numbers separated by full stops, and each number stands for eight bits, or one octet, so it can run only from 0 to 255 — for example 192.168.1.1. Thirty-two bits give about 4.3 billion possible addresses, and because these began to run out, IPv6 was designed with 128-bit addresses written in hexadecimal. Every IPv4 address has a network part and a host part, separated by the subnet mask, and the addresses fall in classes A to E. Option B is wrong because 24 bits is the length of the manufacturer's OUI prefix in a MAC address. Option C is wrong because 16 bits is the size of a port number. Option D is wrong because 12 bits is not the length of any address. Exam tip: IPv4 is 32 bits, a MAC address 48 bits and IPv6 128 bits.

The correct answer is A, REL. An external stylesheet is attached to a page with a link tag written inside the head section, and the tag needs two things: href, which gives the address of the CSS file, and rel, which tells the browser what the linked file is for. Writing rel equals stylesheet is what marks the file as a set of style rules; leave rel out and the browser has no reason to treat the file as CSS, so the page appears unstyled. B is wrong because style is a separate way of writing CSS, either as a style block in the head or as an attribute on one element, and it has no part in linking an external file. C is wrong because body holds the visible content of the page while the link tag belongs in the head. D is wrong because html is the root element that wraps the whole document and has nothing to do with loading a stylesheet. Exam tip: link rel equals stylesheet with href, placed in the head.

The correct answer is A, B2C (Business to Consumer). In the business to consumer model a firm sells goods or services directly to the person who will use them, and Amazon's retail store is the best known example: a shopper opens the site or the app, puts an item in the cart and buys it, with no wholesaler or trader in between. Every e-commerce model is named in the same way, by who stands at each end of the deal, so learning the four pairs is enough to answer most questions on this topic. B is wrong because business to business means one firm selling to another, the way a parts maker supplies a car factory or IndiaMART links wholesalers. C is wrong because consumer to business is the reverse, where an individual offers a service to a company, as a freelance designer does on a bidding site. D is wrong because consumer to consumer is one individual selling to another, as on OLX or Quikr. Exam tip: B2C is Amazon retail, B2B is IndiaMART, C2C is OLX and C2B is freelancing sites.

The correct answer is A, Modulator. A modulator changes the form of a signal: it loads the digital bits produced by a computer onto an analog carrier wave so that they can travel over a telephone line, a cable or a radio link. The reverse device, a demodulator, recovers the bits at the far end, and the two together make the modem, whose very name is short for modulator-demodulator. Option B is wrong because a mouse is a pointing input device; it sends position and click data to the computer but does not convert one form of signal into another. Option C is wrong because a plotter is an output device that draws large line diagrams, maps and engineering drawings with pens on paper. Option D is wrong because a keyboard is an input device that turns keystrokes into character codes for the processor, which is coding rather than signal conversion between digital and analog forms.

The correct answer is C, 110010111. Octal has base 8, and because 2 raised to the power 3 equals 8, every octal digit expands into exactly three binary bits. Take the digits of 627 one at a time. The digit 6 becomes 110, the digit 2 becomes 010 and the digit 7 becomes 111. Writing them in the same order gives 110 010 111, that is 110010111. A quick check works the other way: grouping 110010111 in threes from the right gives 110, 010 and 111, which read back as 6, 2 and 7. Option A is wrong because 111010110 reads as 7, 2 and 6, which is octal 726. Option B is wrong because 110010110 ends in 110 and so reads as 626. Option D is wrong because 011010111 reads as 3, 2 and 7, that is octal 327.