What software and hardware are
Hardware is the physical parts of the computer ie, the box, monitor,
keyboard and mouse.
Software is the programs running on the computer ie, Word, Excel and
Windows operating systems.
The different categories of software
Operating systems - enable the user to interact with the computer. Example
O/S are - Windows 95, 98, DOS and Unix.
Languages - enable developers to write software that they and the computer
can understand. Example languages are - Basic C, Pascal, Java and Visual
Basic.
Applications - enable users to do things on the computer without too
much technical knowledge. Example applications are - Word, Excel and CorelDraw.
What binary is, and how it relates to denary
Binary is a number system to the base 2 i.e. its only numbers are 0 and
1
Denary is a number system to the base 10 i.e. its only numbers are 0,1,2,3,4,5,6,7,8
and 9
Conversion table:
|
Denary number
|
Binary equivalent
|
|
1
|
1
|
|
2
|
10
|
|
3
|
11
|
How a computer uses bits to represent information
Each character on a keyboard is represented by a standard, unique binary
number.
The computer interprets the characters into binary numbers for processing.
All data, be it text, pictures, programs or sound can be represented
in binary for the computer to understand.
What analogue and digital mean
Analogue 'electrical signal that varies in sympathy with some sort of
physical quantity. This electrical signal can represent things like temperature,
velocity and sound. With an audio signal the current varies with the air
pressure of the sound signal.' (Course material)
Digital is where the transmission signal is converted to 1s and 0s and
transmitted electronically by either electronic pulse switched off/on or
light rays switched off/on (fibre optic).
The main components of a computer and their functions
Microprocessor - computers brain, where the calculations take place
CPU consists of 3 units:
Arithmetic and Login Unit (ALU) - does the actual work of the arithmetic
Control Unit - controls the flow of data from memory to the ALU
Memory - storage place for data/information
Motherboard - circuit board housing the CPU microprocessor, the 'clock
chip' for synchronising all its actions and ROM (Read Only Memory) chips.
Cards (slot-in circuit boards) - slot into the motherboard to allow I/O
devices such as keyboard, mouse and monitor to be attached and communicate
with the computer.
RAM (Random Access Memory) chips - store data the computer is currently
using and needs to get at fast.
Hard disk drive - permanent storage device (is not erased when switched
off) holds your files and folders. Other storage devices include CD Rom (read
only unless writable) and Floppy disk (read and write).
Buses – transport the data via cables to the microprocessor and all around
the computer.
The factors that affect the power of a computer
Microprocessor chip – depending on the size/specification/transistors
on them, they can perform more functions.
Clock speed – cycles per second - the higher the faster.
Word size – 64-bit faster than 32-bit, both the microprocessor and the
buses need to use the same word size. The higher the word size the more
complex the data that can be processed/manipulated.
RAM – provides memory space that the computer needs to run applications
and system commands, such as waiting for a mouse click. The more space in
RAM the more applications you can have running. If you run out of RAM the
computer can use a temporary space on the hard disk.
The difference between mainframes, minis, workstations and PCs
Mainframe – used for large data handling tasks by large companies and
universities.
Mini – small mainframe, powerful, special-purpose computer and replacing
mainframes for many functions.
Workstation – powerful PCs based on specialised microprocessors. Used
for special engineering tasks. Typically part of a network.
Personal Computer (PC) – individual use, usually stand-alone but may
be networked. Used for individual computing power such as word-processing.
Computer terminology, such as RAM, ROM, CPU, bytes, kilobytes, data,
instructions, I/O, motherboard, buses and words
RAM (Random Access Memory) – Memory that can be read from or written
to by a computer or other devices.
ROM (Read Only Memory) –A memory chip that contains information that
cannot be modified.
CPU (Central Processing Unit) – Contains the ALU which does the arithmetic,
the Control Unit which controls the flow of data and the Memory where the
data is stored.
Byte (8 bits) – A unit of data that represents a single character. Some
single characters use more than one byte.
Kilobyte – 1000 bytes or 8000 bits, a bit being either a 1 or a 0.
Data – Information the computer program is working with.
Instructions – These are what the computer uses to manipulate the data.
I/O (Input/Output) – Devices such as keyboard and mouse input data to
the computer while and output devices would be a monitor or printer.
Motherboard – A circuit board housing the CPU, RAM, ROM and other circuits
boards for input/output devices to be connected.
Buses – Cables used to transfer data around the components of a computer.
Words – Basic units the computer manipulates when it is performing an
action. A unit could be 32-bit, 64-bit and more.