1. Systems Software

2. Starter – give me an example of each of these. What are they?
User interface
Operating System
Peripheral

3. What is an operating system?
Core system which allows a computer to run as a useful device.
Manages hardware, user interface and other software running.
Without an operating system a computer is just a collection of components heating up a room, no one would be able to make any practical use out of it.

4. Types of operating systems
Windows & Linux – for personal computers
MAC OS – for macs e.g. IOS iphone
Unix – for mainframes PC’s
Symbian, Android – for mobile phones

5. What is an operating system responsible for?
interface - provides a user interface so it is easy to interact with the computer
manages the CPU - runs applications and executes and cancels processes
multi-tasks - allows multiple applications to run at the same time
manages memory - transfers programs into and out of memory, allocates free space between programs, and keeps track of memory usage
manages peripherals - opens, closes and writes to peripheral devices such as storage attached to the computer
organises - creates a file system to organise files and directories
security - provides security through user accounts and passwords
utilities - provides tools for managing and organising hardware

6. Explain what the need for the following functions of an operating system: user interface, memory management, peripheral management, multi-tasking and security. [10 marks]

7. Memory Management
Memory management is the act of managing computer memory at the system level. The essential requirement of memory management is to provide ways to dynamically allocate portions of memory to programs at their request, and free it for reuse when no longer needed.
Allocates where the memory will be used from when requested.

8. Peripheral devices
Each peripheral is programmed with its own machine code. Each has its own rules that dictate how it transmits data values between the computer and the device. These rules make up a protocol for controlling and communicating with the device.

9. Drivers
The Operating System uses programs called device drivers to manage connections with peripherals.
A device driver:
Handles the translation of requests between a device and computer
Defines where a process must put outgoing data before it can be sent, and where incoming messages will be stored when they are received.
Wakes up the device when it is needed and put it back to sleep when it is not

10. Drivers
An OS will have generic device drivers to enable it to connect to most common peripherals. Some peripherals, however, will have their own drivers that need to be installed before use.
Peripherals that use the same protocol may be controlled by the same driver. If a number of identical game controllers are plugged in, each device will store its data in a different place so they do not interfere with each other.

11. User Interface
The OS provides a user interface (UI), an environment for the user to interact with the machine. The UI is either graphical or text-based.

12. User Interface Graphical user interface (GUI)
The OS on most computers and smartphones provides an environment with tiles, icons and/or menus. This type of interface is called the graphical user interface (GUI) because the user interacts with images through a mouse, keyboard or touchscreen.
Command line interface (CLI)
An OS also provides a method of interaction that is non-graphical, called the command line interface (CLI). This is a text-only service with feedback from the OS appearing in text. Using a CLI requires knowledge of the commands available on a particular machine.

13. Multi-tasking
The OS makes it possible to run several programs at once. Several programs can be stored in RAM at the same time, however only one program at a time is processed by the CPU. Programs can be in one of three states:
running
waiting
runnable
Only one process can be running at any one time. CPUs are extremely fast, so if a program is processed for even a short time it can do quite a lot. The OS decides the best way to swap between running, runnable and waiting processes. It controls which process is being executed by the CPU at any point in time, and shares access to the CPU between processes. The job of working out when to swap processes is known as scheduling.
Swapping happens so fast that it appears that all processes are running at the same time. When there are too many processes, or some of them are making the CPU work especially hard, it can look as though some or all of them have stopped.

14. File Management
The OS manages how data is organised into files. This makes it easier for the user to see files using programs like the Windows File Explorer or Mac OS X Finder. The OS organises where and how files are stored, deleted, read, found and repaired. It detects errors such as missing disks or incorrect file names, and informs the user that errors have occurred.
Each file has a unique name and the OS maintains a set of look-up tables that relate file names to locations on storage drives.
Hierarchies
File systems work in a similar way to the way that libraries organise books. Folders and directories correspond to different sections of the library. Inside each folder can be other folders (sub-sections within a subject) and files (the books themselves).
File systems can become corrupt if a computer is turned off before a program is copied to a new location.

15. Exam Q
Explain what the need for the following functions of an operating system: user interface, memory management, peripheral management, multi-tasking and security. [10 marks] An operating system is the core system on a computer which controls hardware, software and user interface. It has multiple functions such as managing the user interface, memory management, peripheral management, multi tasking and security. The operating system manages the type of user interface it display to the user. There are two types, CLI and GUI. The GUI is graphical user interface. This tends to the be the front end of applications which the user sees and is user friendly including graphics and easy readable text. The CLI stands for Command Line Interface. This is the back end of applications, the coding side which is not user friendly. The Operating system will manage the user interface it displays to the user. Memory management is another area which the operating system manages. The amount of memory it uses for applications and which memory is it going to use. The memory it controls is the RAM space. This memory is used for applications. The amount it needs to load and run. The operating system assigns the amount of memory it needs and controls if it needs to free extra space up from another location in order for the application to be successful. Peripheral management is the management of devices into the computer. The operating system uses device driver programs to manage the peripherals with the computer and how the user can use this peripheral. Each peripheral has its own machine code which is read and executed. This is how the operating system communicates with the devices. Multi tasking within the operating system is allowing more than one application. Multiple applications will have a status. Only one application can be running at once. The others will either be set to waiting or runnable. These applications cannot all be active at once. The operating system manages the statuses of these applications and swaps them as they change process. This is called scheduling. Lastly the operating system can include security. This will include accounts for users with a username and password to enter the OS. The accounts set up will also include data encryption for when the information is entered by the user. This is all a security function within the operating system.
1 mark, good opening line, can give you an extra mark if you have forgotten something further down.
2 marks
2 marks
2 marks
2 marks
2 marks

16. List a range of examples
Software
What are these?
List a range of examples
Operating system
Application software
Utility software

17. Utility software
Utility software includes: system clean up, automatic updates, encryption, defragmentation
Encryption software – https, wireless key, padlock, internet protocols, s over secure connections, windows-bit lock-locks software. Encrypt hardrives - passwords
Defragmentation – process of locating the non-contiguous (not in order) fragments of data into which a computer file may be divided as it is stored on a hard disk, and rearranging the fragments and restoring them into fewer fragments or into the whole file. Clean up scheduled in the background of windows. Just on files.

18. Defragmentation Utilities
Files are stored on a hard drive in available spaces, ideally entire files would be stored together.
However as files are moved, deleted and change in size, lots of small gaps begin to appear on the disk. When writing files to the disk, OS splits files into smaller blocks to fill the gaps.
Over time, the disk becomes more and more fragmented. This makes reading and writing files slower as the read/write has to move back and forth across the disk.
Defragmentation software recognises data on the hard drive to put fragmented files back together. It also moves files to collect all the free space together. This helps prevent further fragmentation.

19. Defragmentation Storing fragments of data. After defragmentation.
Piece of utility software
A fragment is a gap of space located on the hard drive.
Applications/files create data to be able to run, these are split into the gap fragments on the hard drive and stored.
The more fragments stored the less space there is on the hard drive, which slows the running speed down on the OS.
Defragmentation re-organises the fragments so the data for a particular application/file is put together.
Storing fragments of data.
Before defragmentation
After defragmentation.
Organised and located together.

20. Defragmentation
When files are deleted, unused clusters become available for reuse. These can end up being distributed across a drive, especially if the original files were small. If a large file is then written to a drive, its data could be spread across different clusters leading to file fragmentation. Defragmentation involves rearranging the information on a disk so that files appear in continuous sequences of clusters. This will improve file access times. Most modern operating systems run this process automatically.

21. Security (antivirus, spyware & firewalls)
These include:
user accounts - allow the user to allocate specific users and protects personal files and programs from unauthorised access.
encryption - can encrypt data when it is stored, or whenever it is transmitted over a network.
anti-virus software - detects and blocks viruses.
firewall - can be used to filter between trusted and untrusted networks and prevent programs from communicating through the use of ports.
Spyware - Programs that secretly record what you do on your computer are called spyware. They can be used for some perfectly legitimate purposes, but the majority of spyware is malicious. Its aim is usually to capture passwords, banking credentials and credit card details - and send them over the internet to fraudsters.

22. System maintenance

23. Types of Software

24. Open Source Open source
"Source code" is the part of software that most computer users don't ever see; it's the code computer programmers can manipulate to change how a piece of software—a "program" or "application"—works. Programmers who have access to a computer program's source code can improve that program by adding features to it or fixing parts that don't always work correctly.
MySQL (database) Example

25. Closed Software
Only the original authors of proprietary software can legally copy, inspect, and alter that software. And in order to use proprietary software, computer users must agree (usually by signing a license displayed the first time they run this software) that they will not do anything with the software that the software's authors have not expressly permitted. Microsoft Office and Adobe Photoshop are examples of proprietary software.

26. Question?
What is the fundamental difference between open Source and Closed Sourced Software?

27. Off the Shelf Software
Short for commercial off-the-shelf, an adjective that describes software or hardware products that are ready-made and available for sale to the general public. For example, Microsoft Office is a OTS product that is a packaged software solution for businesses.

28. Bespoke software/Custom Software
Custom software (also known as bespoke software or tailor-made software) is software that is specially developed for some specific organization or other user.
E.g. Sims for schools and Show my homework etc…

30. Question?
What is the difference between Off the shelf Software and Bespoke Software?

31. Proprietary Software
Proprietary software is software that is owned by an individual or a company (usually the one that developed it). There are almost always major restrictions on its use, and its source code is almost always kept secret.
Proprietary software (sometimes referred to as closed source software) is software that legally remains the property of the organisation, group, or individual who created it. The organisation that owns the rights to the product usually does not release the source code, and may insist that only those who have purchased a special licence key can use it.

33. Discuss the relative merits of custom written, off the shelf, open source and proprietary software.