Computer Awareness Mixed Quiz: Set 13

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.

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.

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.

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.

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.

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.

Hexadecimal has base 16, and because 2 raised to the power 4 equals 16, exactly four binary bits make one hexadecimal digit.

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.

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.

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.

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.

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.

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.

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 format is named after the committee of experts that drew up the standard, which was published in 1992 for compressing photographs.

An IPv4 address, which is what the question means by an IP address, is thirty-two bits long.

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.

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…

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.

Octal has base 8, and because 2 raised to the power 3 equals 8, every octal digit expands into exactly three binary bits.