Transcript systems software - TeachingComputing.com

Computer Software
Software=The computer programs
(sequences of instructions) that tell
the computer what to do in response
to a command or some event.
General Overview
From the Specification….
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Students should be able to
describe the different roles and
functions of systems software and
applications packages.
•identify the features of common applications found in business, commercial and
industrial applications: eg stock control, order processing, payroll, process control,
point-of-sale systems, marketing, computer-aided design (CAD), and computer-aided
manufacture (CAM);
•n. identify and justify generic applications software for particular application areas, eg
word processing, spreadsheets, desktop publishing (DTP), presentation software,
drawing packages;
•
Classification in Biology
Software
Systems
Applications General Purpose
Special Purpose
Bespoke
Correct?
Systems
Applications
General
Purpose
Special
Purpose
Bespoke
Operating Systems
Word Processing
Software
Microsoft Excel
Accounting
Program
Spreadsheet
Software
Microsoft Access
Stock Control
System
John and Co.
Accounting System
(made specifically
for the company –
custom made!)
Library programs
Utility Programs
Programming
Language
Compilers,
Interpreters and
Assemblers
Databases
Software
Desk Top
Publishing Software
Microsoft Office
Suite
Adobe Suite
Payroll System
Classification of Software
Software is the general term to classify all
programs that run on a computer.
 There are several CATEGORIES of
Software.
-systems software
-general purpose software (generic)
-special purpose application software
-bespoke software.
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Can human Consciousness be re-created.Or downloaded
onto a disk?
Types of Software
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Systems Software
Application Software
General Purpose Application
Software
Special Purpose Software
Bespoke or “off the shelf”
5 MAIN CATEGORIES…….
Systems Software
1.
Operating System
2.
Library Programs
3.
Utility Programs (these are programs
desgined to make life easier for
computer users)
4.
Programming language compilers,
interpreters and assemblers
Systems Software

Systems software perform tasks
that are needed to run on the
computer system
SYSTEMS SOFTWARE
1. Operating System
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XP
Every Computer needs an OS to act as an
Interface between the user and the hardware
It provides us with a VIRTUAL MACHINE
The OS does stuff that we don’t need to know
how it was done…
User can press: SAVE –we don’t know how that
happens (the OS takes care of that)
A program called a device driver for instance
takes care of printing…
SYSTEMS SOFTWARE
2. Library Programs
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These programs are available to all
users of a multi-user system to do
tasks that are common and required
by all
For instance –a routine that
searches for lost files, restores
them, and saves them, is stored in
a library.
SYSTEMS SOFTWARE
3. Utility Programs
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Designed to make life easier for
computer users.
i.e search for lost files
Sort files
Copy onto a CD/magnetic disk
Compress to a ZIP file
SYSTEMS SOFTWARE
3. Programming language compilers,
assemblers and interpreters.

These are basically the software
that TRANSLATE the words of a high
level program (such as VB) to
machine code …to 1’s and 0’s
Statement
In
VB
Compiler
Interpreter
assembler
1010101
10101
10101011
1010101000
Applications Software
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Software designed to carry out some task
for the user that is primarily
INDEPENDENT of computers, such as
writing a letter…or processing orders….or
invoices.
Generic Software
GENERAL PURPOSE APPLICATION
SOFTWARE
SPECIAL PURPOSE APPLICATION
SOFTWARE
Word Processing, DTP, CAD, General Software…usually sold on a CD
Microsoft Office, SunStar, Serif. Software that can do many tasks.

Application software such as PAYROLL software, accounts, or stock
Control system…or software to help you fill in a tax return. It is designed
To do ONE particular task. (a specific task)
OFF THE SHELF
Generic Purpose SOftware
Software Suites
OFF THE SHELF
Special Purpose Software
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Software to perform a specific task
Software to help fill in an income
tax return
Stock control System
Payroll System
Bespoke Software
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This is software that is designed for
a specific purpose AND for a specific
organisation! It is built specifically
and custom-made for them!
Bespoke software: written to the
exact specification of the customer.
OFF THE SHELF OR BESPOKE?
Off the Shelf -advantages
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?
Off the Shelf -advantages
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Less expensive
More collaboration (can talk to other
users of the software)
Can be bought and installed immediately
Software has been tried and tested –so
will contain fewer bugs
Software well documented
Easily replaceable and can be found
anywhere
BESPOKE -advantages
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Designed to do exactly what the user
wants
Has no unwanted features
Can be written to run on specific
hardware
Can be integrated with existing software
There may not be a suitable software
package on the market (on the shelf!)
Key Words
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DTP –desk top publishing (publisher,
Serif)
Generic –Same as General
Common Application Software Found in
Business
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eg stock control, order processing,
payroll, process control, point-ofsale systems, marketing, computeraided design (CAD), and computeraided manufacture (CAM);
Generic Applications (GENERAL)

generic applications software for
particular application areas, eg word
processing, spreadsheets, desktop
publishing (DTP), presentation
software, drawing packages;
Word Processing –for writing letters
DTP –for leaflets and newsletters etc
Presentation Software –power point –for multimedia presentations
Drawing Packages –for graphics, detailed images
Spreadsheets –for budgeting and calculations.
What is the difference between DTP
and Word Processing?
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DTP is text-orientated
DTP is design-layout orientated.
What is an Operating System?
http://swc.scipy.org/lec/img/shell01/operating_system.png
OPERATING SYSTEM -definition
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An 'operating system' (commonly
abbreviated OS and O/S) is the
software component of a computer
system that is responsible for the
management and coordination of
activities and the sharing of the
resources of the computer.
What does it do?
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It provides an INTERFACE between
the Hardware and the User
Common contemporary operating
systems include Microsoft Windows,
Mac OS, Linux and Solaris.
Next Week….
The systems development life cycle
• Generic applications software
• Operating systems
• User interfaces
• Utilities
1.
2.
3.
4.
5.
6.
7.
8.
9.
Candidates should be able to:
describe the stages of the systems life cycle;
explain the importance of defining a problem accurately;
describe the function and purpose of a feasibility study;
explain the importance of determining the information requirements of a system and describe different
methods of fact finding, including questionnaires, observation, and structured interviews, highlighting the
advantages and disadvantages of each method;
describe what is involved when analysing the requirements of a system, explaining the nature of the
requirements specification and its content, including current data structures, inputs, outputs and
processing represented in diagrammatic form (data flow diagrams, system flowcharts), identify
inefficiencies/problems in the current system;
describe a design specification including input design, diagrammatic depiction of the overall system,
processing, data structure design and output design;
explain the importance of evaluating the system, and how to identify the criteria used for evaluation;
explain the content and importance of different types of documentation at different stages in the system
life cycle, including the technical and user manuals;
explain the importance of system testing and installation planning;
When you Turn a Computer On
You don’t need to know
What is happening behind the
Scenes. The OS does this for you.
The technicalities of what happen when you PRINT
are UNKNOWN to you. Handled by a DEVICE DRIVER (type of small program)