4.6: section 4: hardware and software

-the physical electrical and electro-mechanical components of a computer system

• the programs that make a computer function - system and application

• software needed to operates, controls and maintain the computer’s hardware and application programs • operating systems, utility programs, libraries, translators

• a program or set of programs that manage the operations of the computer for the user • manages and controls access to the computer’s resources. • Acts as an interface between the user and the computer’s hardware • uses a virtual machine to hide the true complexity of the computer from the user • OS is held in permanent storage – e.g. on a hard disk

-designed to carry out housekeeping tasks -tasks include data backup, defragmenting hard drives (reorganising data on a hard drive in order to improve speed of access), data compression and encryption.

• collection of precompiled routines written to carry out common tasks for other programs • libraries must be imported into program code in order to be used

• software used to translate high level programming code into machine code • complier, assembler, interpreter

• machine-oriented languages which have no built-in functions but can access specific registers in the processor. • machine code, assembly language

• abstracted problem-oriented languages which need to be translated to be understood by computers • imperative

• a programming language made of binary or hexadecimal instructions which a computer can respond to directly. • Opcode (operation code)- the actual instruction • all the instructions that a computer can understand and execute. -Operand- the value that the instruction uses or manipulates.

• a low-level symbolic code converted by an assembler. • Each opcode is replaced with mnemonic- made it easier to understand what the operator meant • The operand was replaced by a decimal (hexadecimal) number

• fast as they don’t need to be translated • memory efficient • can directly communicate with hardware devices

not portable • difficult to debug and maintain as it is more error prone • difficult for humans to understand

• designed to solve specific problem types by writing a set of instructions that say how a problem should be solved • the instructions are then translated from high-level source code into executable object code. -

• relatively easy to learn • easier and faster to write compared to low level languages • easier to understand, debug and maintain as code uses english • machine independent so its portable • many available built in functions

• slow execution as they need to be translated with a compiler or interpreter • cant communicate directly with hardware

• memory management • Process scheduling • Backing store management • Peripheral management of all IO devices

to hide the complexities of the hardware

o programs that complete a specific task for the user. Examples of application software include word processors, web browsers and spreadsheet software.

• slightly easier to understand compared to machine code - debugging is easier compared to machine code

programs are processor specific -assembler must be used before a program is excecated