05b - Software - Applications software and programming languages

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05b - Software - Applications software and programming languages Powered By Docstoc
					        GCSE ICT - Software – Applications software and
                    programming languages
Applications software                              It is very popular because it is usually
 Applications software is designed to              relatively cheap, well tested, and has wide
  perform specific tasks.                           support (e.g. easy to use manuals and
 There are three main types of application         tutorials).
  software:                                        General purpose software is also known as
  o Applications packages                           ‘content free software’.
  o Tailor-made software
                                                  Programming languages
  o General purpose packages
                                                   A program is a set of instructions that the
Applications packages                               computer can understand.
 Examples of applications packages include:       Programs are written in programming
  o Word processing software – MS Word,             languages, and there are several different
    WordPerfect                                     languages that can be used.
  o Spreadsheet software – MS Excel, Lotus         The choice of programming language
    1-2-3                                           depends upon who is writing the program
  o Database software – MS Access                   and what they want it to do.
                                                   There are two levels of programming
Integrated software                                 language. These are:
 A common type of applications software            o Low-level languages (including machine
  found on home personal computers is                  language/machine code and assembly
  integrated software.                                 language)
 This is a software package that includes a        o High-level languages
  collection of application software that
  shares a common set of commands.                Low-level languages
 A typical integrated software package will       Low-level languages are easy for the
  include:                                          computer to understand but are more
  o A word processor program                        difficult for the programmer to write.
  o A spreadsheet program                          The lowest-level is machine language or
  o A database program                              machine code.
  o A graphics manipulation program                This consists of series of 1s and 0s and is
 Integrated    software     packages   have        often machine specific (i.e. it will only work
  advantages and disadvantages.                     on one type of computer).
 Advantages:                                      All other programming languages have to
  o Easier to use                                   be translated into machine code in order to
  o Moving data between programs within             work.
  the package is easy                              Assembly language is not as low-level a
  o Cheaper than separate programs                  programming language as machine code.
 Disadvantages:                                   It uses simple instructions such as ADD,
  o Tend to have weak areas (e.g. better at         SUB, and LDA.
     word processing than spreadsheets)            Assembly language needs an assembler to
  o Data is not easily moved to programs            translate it into machine code.
     that are not part of the package
  o Cheap is not always best!                     High-level languages
                                                   High-level languages are easier to use
Tailor-made software                                because they are designed with the
 Tailor-made software is very expensive            programmer in mind.
  because it is designed for a specific            They are not machine-dependent and allow
  purpose.                                          a program to be written so that it can be
 It is software that is not available ‘off the     used on many different computers.
  shelf’ and is usually written or developed       Many of the instructions in high-level
  for large organisations (e.g. government,         languages are in American English.
  banks,         insurance         companies,      Examples of high-level languages are:
  manufacturers).                                   o COBOL – is used mainly for business
                                                       data processing.
General purpose software                            o BASIC – is mainly used as an
 General purpose software is not specific to          introductory programming language in
  a particular user (e.g. MS Word), and may            schools.
  be capable of development into tailor-made        o C++ - is a popular language for
  software (e.g. MS Access).                           developing commercial software.

05b - Applications software and programming languages
        GCSE ICT - Software – Applications software and
                    programming languages
  o LOGO – is mainly used in schools to        Tasks:
    teach pupils how to write simple control   1.   What are the three main types of
    programs.                                       application software?
  o JAVA – is particularly suited to writing   2.   What     are     the    advantages  and
    programs that will search the Internet.         disadvantages of integrated software?
  o HTML – Hyper Text Mark up Language is      3.   Why would tailor-made software not
    used to develop websites.                       normally be used on a home personal
Translation languages
                                               4.   Why is general purpose software
 Translation languages convert program
                                                    popular with home and business
  commands into machine code.
                                                    computer users?
 There are two main types of translation
                                               5.   What are the two levels of programming
  languages.                                        language?
 These are:                                   6.   What does a low-level assembly
  o Interpreters                                    programming        language    need   to
  o Compilers                                       translate it into machine code?
 Interpreters convert each instruction into   7.   List    6      high-level   programming
  machine code, and then carry them out.            languages and their main uses.
 Compilers convert the whole program into     8.   What     do     high-level  programming
  machine     code   before   carrying   the        languages need to translate them into
  instructions out.                                 machine code?
                                               Extension Task:
                                               If you were asked to design a database for a
                                               home user would you base your design on an
                                               integrated software package, general purpose
                                               software, or a programming language? Please
                                               explain your choice.

Relationship between assemblers, compilers,
              and interpreters

05b - Applications software and programming languages