Computer Studies/ ICT

FILES A computer file is a block of arbitrary information, or resource for storing information, which is available to a computer program and is usually based on some kind of durable storage. Computer files can be considered as the modern counterpart of paper documents which traditionally are kept in offices and libraries’ files, and this is the source of the term. Files are collection of data in a permanent storage media such as hard drive, CD or DVD ROM, floppy disk, memory card, flash drive etc. FUNCTIONS OF FILE (i) It provides machine executable code which is used to run application programs and the operating system. (ii) It stores application programs or operating system configuration information. (iii) It stores used data by the user such as Ms Word. ORGANIZING THE DATA IN A FILE Information in a computer file can consist of smaller packets of information (often called “records” or “lines”) that are individually different but share some trait in common. The way

An output device is a peripheral device that allows a computer to communicate information to humans or another machine by accepting data from the computer and transforming them into two categories. (i)                  Output that can be readily understood and used by humans. (ii)                Output to secondary storage devices that hold the data to be used as input for further processing by computer. Output that can be understood by humans can be in the form of hard copy or soft copy. HARD COPY It is output on paper and can be read immediately or stored and read later. This is a relatively stable and permanent form of output. SOFT COPY It is usually a screen – displayed output. It is a transient form of output and is lost when the computer is turned off. Devices confirming to above specifications are classified as follow: (A) Soft copy (i) Virtual; graphic card, VDU (Visual Display Unit)/ Monitor, projector etc. (ii) Sound; sound card, speaker, computer spee

REGISTERS Registers are temporary storage area for instructions or data. They are not a part of memory; rather they are special additional storage locations that offer the advantage of speed. It works under the direction of the control unit to accept, hold, and transfer instructions or data and perform arithmetic or logical comparisons at high speed. Most operations are done on the register; the processor can’t directly perform arithmetic in memory. For example, if you want to add 1 to a memory address, the processor will normally do this by loading the initial value from memory into a register, adding 1 to the register, and then saving the value back to memory. The width (in bits) of the processor’s register determines how much data it can compute with at a time. This is sometimes used to label the processor’s size. ADDRESS A memory address is an identifier for a memory location, at which a computer program or a hardware device can store data and later retrieve it. In modern

INPUT DEVICES An input device is a peripheral device through which data are entered or fed and transformed into machine – readable form. Before computer processing, data must be entered into computer by an input device so that they can be translated into a machine – readable form. EXAMPLES OF INPUT DEVICE KEYBOARD One of the most common and familiar input device is the standard keyboard. Computer keyboard are of two sizes 84 keys or 101/102 keys, but now 104 keys or 108 keys. It contains the following sections: (i)                  Numerical keypad: It is used to enter numeric data or control cursor movement.  (ii)                Function keys: These are arranged in a row along the top of the keyboard. Each of them has unique meaning and is used for some specific purpose. (iii)              Special keys such as Enter, shift, Caps lock, Space bar etc. (iv)              Alphabetic key pads: used to enter letters (A – Z) and digital keys (0 – 9) (v)                A