UNIT 2 -
SOFTWARE
Software is the program that runs
on a computer
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Includes:
Application software and system software – operating systems, drivers, film
ware, servers
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System software – controls and makes use of
hardware
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Applications software – programs
which world tasks. Microsoft word
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Software is written by programmers using various
programming languages
Alan
Turning thought of a device which will do any task when given the
instruction to do so
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Instructions are loaded into the RAM from the hard
drive and fetched – decoded and executed by the CPU. These instructions are a
program i.e. software
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CPU understands Binary – machine code long winded and
difficult. So programmers use high level
Software
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The
operating system – necessary to run all computing devices
Functions
of The operating system
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Sits between your applications and hardware of your
computer
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Deals with controlling all aspects of the computer
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Makes it easier to write applications
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Kernel is the lowest level of OS and controls the
hardware
Functions –
Manages hardware
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Manages hardware and software resources of the system
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In a desktop computer theses resources include:
processor, memory, disk space and more
- EG; when you wish to save a document the application
passes the document to the OS
- OS needs to use different instructions to save to a
hard disk compared to solid state drive
- OS uses special software called device driver to
translate specific instructions
Each different piece of hardware will have a device
driver to communicate between the OS and hardware.
Device
drivers are used to communicate
Peripheral Management
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Computer
has peripherals in order to input output and store instructions data. The
signal which controls them is a device driver controlled by the software. Each
peripheral has its own driver depending on manufacturer there are some genetic
device drivers ion windows 7/8
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Application
software doesn’t need to know about the devices it passes on requests from the
users to the program
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Interpret
signal id generally by a program which tells the Operating System to stop a
program using a device and make the CPU do a task for another programme with
the device
User
setting
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Applets – a small application that does a single task
Firm ware
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The initial starts up before device drivers are loaded
on. This is stored permanently on ROM chips e.g. BIOS- basic input output
system which does initial start-up of a computer.
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Also runs on a simple devices such as TV remote or
camera
Server
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The word server applies to the hardware (the computer) and software
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Server software resounds to the requests of other
programs (clients). It is used on the internet and on smaller networks like we
have in school e.g. when we ask to print – the server software processes the
request and delivers the data to the client
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Any
computer can be a software, just install software data
Functions
Multitasking
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The
operating system controls multitasking making it look like the computer is
running more than one program at once
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It
does this by switching between programs very quickly
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The
#CPU is so fast there are times when the RAM can’t keep up (video buffing) so
the CPU is instructed by the OS to do something in this time
Memory management
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The
OS controls the memory management allocating RAM space to programs
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Determines
how much memory each app had and what to do if the memory becomes full
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Manages
virtual RAM
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Tracks where data and programs are at any one time to
make efficient use of the memory and ensure nothing is lost
Security
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OS must protect processes from each other and users=s
from each other because PCs are used by multiple users at home or on a network
and on the internet.
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Manages
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Tracks who owns each file and what privileges the user
has on each file/folder e.g. admin rights
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Passwords to login allow you to protect your phone
from other users but also allow you to use networked computers on your own
profile.
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OS provides a user interface
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This is what the other user sees when they wish to use
the computer system
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There are different types of user interfaces, each
with their own advantages and disadvantages
User
interface – command line interface
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This is used to be the only way to operate a computer
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Commands are typed in at a prompt to run programs or
perform actions
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Does not need a powerful computer
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Fast to get things done
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Not suitable for beginners as you need to know the
commands before you can operate the computer used by technicians
Menu
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Often seen on devices where the input device is
limited TV remote
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As all the options are there to be seen Simple and
easy for novices
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Simple to navigate and easy to determine what to do
Graphical
user interface GUI
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Popular with ease of use
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Is the way we most often control the computer
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Programs run in windows, icons represent files and
apps
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Actions may have metaphors dragging a file on to the
trash can mean delete the file for example,
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Intuitive and easy for beginner
Voice
recognition
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Still evolving but is becoming more widely used e.g.
call centres ask the user to say numbers and yes/no. apple iPhone has voice recognition
as part of OS – Siri
Windows
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Windows Operating System currently 8.1 keeps the GUI
and all applications looking similar so that a user can easily use them. They
all use code that is part of windows itself
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It has a huge range of capabilities, far greater than
OS itself
MAC OS
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On PC this is currently Yosemite. This is based on a
UNIX system and has led to the iOS for mobile devices. It is a proprietary
system which has enabled new ways of thinking about how a user interacts with
the OS
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More reliable artists media
LINUX
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Open source range of OS’ based on the UNIX Kernal. UNIX
works on command line but the new versions of LINUX run a GUI. It is a small OS
and is therefore fast and uses less memory. It is very versatile and is used on
servers and mobile devices – ANDROID
