What is systems?
Software is detailed instructions which guides the hardware to perform a particular task
What does systems software control? Why does a computer need it?
- Software controls the processing and movement of data within a computer system
- Computer needs to software to tell it what to do and the computer needs hardware to do the work
What are the two types of softwares?
- System software
- Application software
What does the systems software do? What does it include?
- Carries out functions such as starting the computer, loading the application software, storing files
- Includes operating system and utility software
What is operating system? Where is it stored?
- Software that supervises and controls hardware
- Usually stored on hard disk
What are common operating systems?
Windows, LINUX, Macintosh
When does the operating system start?
Starts automatically when the computer is switched on (known as booting the system)
Explain how the operating system works?
- A ROM chip that contains the BIOS (basic input output system) executes a power-on self test (POST) to make sure hardware is connected and operating correctly
- After the POST is completed successfully, the BIOS loads the operating system
List some tasks the operating systems perform.
Schedule hardware operations, manage memory, control peripheral devices, manage file and system settings
Describe scheduling hardware operations
Scheduling hardware operations– Computers have allot of tasks to perform but can only do them one at a time. So, the operating systems decides when it will perform the task. It does this by time slice which is a fixed amount of CPU time, so each task receives a time slice
Describe managing memory
Memory management– The system must ensure that data is efficiently accessed and not overwritten by dividing available memory between different tasks and swapping data between memory and secondary storage
Describe controlling peripheral devices
Controlling peripheral devices– The operating system provides the communication with all input, output and storage devices, so it uses specific software for each peripheral device known as a driver. An example is, a mouse driver is the software that tells the computer how to receive data from a mouse
Describe managing files
File management– The system organises and keeps tack of files. A file is a collection of data that is known by the file name. File names are followed by a period (.) and file name extension. The file name extension indicates the type of information stored in the file. It makes it possible to add/delete a file, open/close files, copy/move files
Describe system settings
System settings– The operating system is used to change the computer settings, such as background theme, brightness level and time
What is single tasking?
Single tasking– Allows only one task to be performed at a time such a Palm OS system
What is multi tasking?
Multi tasking– Allows many task to be completed at the same time such as Windows operating system
Give an example of a multi user operating system.
Multi-user– Example is UNIX
What does utility software do?
Performs common tasks to support the operation of the computer system.
List the tasks performed by utility softwares
- File compression– reduces size of file to allow more storage of data
- Diagnostic tools– compile technical information about computers hardware and software
- Disk scanner– to detect and solve problems and remove unwanted files on a disk
- Disk defragmenter– reorganises files and unused space on the computers hard disk
- Uninstaller– remove unwanted applications
- Device drivers– to provide communication with peripheral devices
- Back-up utility– to copy entire hard drive onto another disk
- Antivirus program– remove and prevent viruses
What is application software?
Application software is a program used for a specific task. It consists of software packages and custom software
What is a software package?
- It is a complete and documented set of programs supplied to many users
- An example is office suites which contains several application
What do software packages include?
It includes word processing, desktop publishing, spreadsheets, databases, , paint and draw programs, video editing programs, web browsers, presentation software and animation software
What happens when you purchase a new version of a software package?
When you purchase a new version you upgrade your application software
What should you do when your purchase a software package?
Check that your software is compatible and meets the requirements of the operating system
What is integrated software?
Integrated software contains several applications that work together as a stand-alone product
What is custom software? Who is it written by?
- Software written for a customer and is not for several users. It is written to fit specific requirement for a customer, which means it is very expensive
- Written by a programmer using programming language (set of code and rule that allow the computer to operate)
What is low level language?
Low-level languages– Depend on the hardware of the system. They process calculations faster than high-level and they include machine language
What is high level language?
- High-level languages– English like codes. Each statement is like several lines of machine code. It doesn't depend on hardware of the system, so the program is portable
- High-level languages include Java, BASIC, FORTRAN and PROLOG.
What is hardware requirements?
- Software depends on a particular hardware configuration to work effectively
- All software companies state the requirements of their products
How does application software affect hardware requirements?
Application software is available to complete many different tasks, however this affects the hardware requirements since each task may require different data types
What is user interface?
User interface is the way the user interacts with the software
What is the function of the user interface?
Function of the user interface is to provide a way of communicating with the computer for the user
List two common user interfaces.
Two common types of user interfaces are character based user interface (CBUI) and Graphical user interface (GUI)
What is a Character Based User Interface (CBUI)?
- Requires user to give instructions using only characters by typing on a keyboard
- Commonly used on devices with limited memory such as phones and microwaves
Give a history on CBUI
- OS/360 was the first widely used operating system like this in
- 1964 MS-DOS (Microsoft disk operating system) also uses this. Was very popular and became industry standard for IBM compatible computers in 1980s
- Still used
- UNIX is a multi user system which enables timesharing of a host computer with several other computers at the same time. It is widely used on internet servers
What is a graphical user interface? Give an example of a GUI
- Allows user to give instructions using by using a mouse, clicking icons and menus
- It is an easy-to-see and consistent interface, Windows is a popular GUI
What are the features of a GUI?
- Windows– Things on a computer appear in a frame called a window. Several can be opened at once. They can be closed, resized, moved, minimised or maximised
- Icon– A small program which represents a program, file, folder or shortcut
- Menu– An onscreen list of available commands and tools
- Dialog box– A small area on screen in which the user is prompted to provide information or select commands
- Desktop– On-screen work area where the above appear
- Trash bin– A folder for deleted items
Give a brief history of the GUI
- Was used initially by Xerox Corporation but Apple Macintosh made is popular
- Ms Windows introduce the GUI to IBM compatible computers 1985
- Mac OS and Windows added features o make GUI easier to use
What is LINUX?
- It is freely distributed and supported
- Developed as a scaled down version of UNIX
- GUI is provided using a shell called KDE
- Example of open source software.
- Programmers have improved Linux
Compare graphical user interface with character based user interface
- GUI have the same consistent appearance as operating systems do, which makes it easier to understand and learn commands as compared tom CBUI
- GUI’s have undo and cancel buttons to reverse actions (more forgiving)GUI’s however, requires faster processors, more memory, high quality screens, more disk space and complex software
What do windows display?
- Windows display contents of files, folder and programs
- More than one window can be opened at a time and are stacked on one another
What does the title bar in a window indicate?
The title bar is at the top of the window, the left side contains the name of the file
What are the special buttons used to rearrange windows?
- minimise —reduces the window to a button on the taskbar; click the button to reopen the window
- maximise —increases the window so that it can be viewed using the entire screen
- restore —returns the window to its previous size after it has been maximised
- close —closes a window or exits a program.
- resize—point to the border of the window until it turns into a double-headed arrow, then drag the borders to the required size
- move—drag the title bar to its new position
What is a menu?
- Menus are onscreen lists of available commands and tools and is located below the title bar
- Menus are either drop down or pop up
How is a menu confusing?
- light grey options are unavailable—the user needs to perform another task before selecting this option
- options with an arrow open to a submenu—pointing to the arrow opens the submenu options marked
- indicate the current active option— clicking this option turns it off options followed by dots open with a dialog box that requires further information
What is scrolling?
- Scrolling is the method of moving the window is contents don’t fit in window
- Documents can be scrolled up, left, down, right using scroll bars
- Pressing scroll bars provides a scroll tip
What is a dialog box?
Dialog boxes are message boxed requesting further info
How is information entered into dialog boxes?
- Tab- Appears at top of page when there are two or more pages of options
- Option box– Selects one option from a group
- Check box– Click to turn an option on or off
- List box– Presents user with two or more options which is viewed with scroll bar
- Drop down list– Only one item is visible and rest is shown by clicking an arrow
- Spin box– Text box that has control to change setting by set amounts
- Slider– Drag up, down or sideways to increase/decrease setting
- Command buttons– Ok to confirm, Cancel to quit
Name the consistent elements in all GUI's.
- A new document is needed to start work in an application
- Opening a document retrieves a previously saved document
- Closing a document removes the active file but keeps the application running
- Mistakes are correct using ‘undo’ or ‘redo’Cut and paste moves a block of text or graphic to another place
- Copy and paste copies a block of test or graphic to another place
- Drag and drop is an easy way to move text or graphic in a short distance within a doc
- Printing a document transfers a copy of it onto paper
- Find test with the Ctrl+F, locates specific characters, symbols or phrases
- Save documents which is stored permanently on a secondary device