User Interface

d) Describe different types of user interface: forms, menus, GUI, natural language and command line, suggesting the characteristics of user interfaces which make them appropriate for use by different types of user

Which type of user interface is the most suitable depends on many factor, consider :

- Does it need to be displayed on a tiny screen?
e.g mobile phone, if yes then its going to be difficult to use a GUI, probably a menu driven interface is the most suitable.

- Does it have very specific task to do?
e.g a software backup programme. This can run in the background without even a monitor - so no point designing a fancy menu or resource hogging GUI - a simple command line interface would do.

- Does it have to interact with many different types of user?
Can it be used with a colour monitor? In this case a GUI is probably the best choice.

Forms:

When a user is required to enter data such as sales invoices or customer names and addresses, it is common to have a 'form' displayed on the screen for the user to fill in.

Menus:

1) Full Screen Menu. This type of menu is often used as the 'front end' of an application. It stays on screen until the user makes a choice.

2) Pull-Down Menu. This type of menu is displayed along the top of the screen, and when the user clicks on an item, a sub-menu appears. The menu is always present whatever screen the user is looking at in the application.3) Pop-up Menu. The menu pops up in response to, say, a click of the right mouse button on a particular area of the screen

Command Line: With this type of interface very little help is given to the user who has to type a command such as, for example using MSDOS PROMPT: to delete a file. DIY! lCommands enable a user to quickly and concisely instruct the computer what to do but they do require the user to have a knowledge of the commands available and the syntax for using them. e) describe the purpose of a range of utility software e.g. disk formatting, file handling, hardware drivers, file compression and virus checkers

Disk formatting is the initial part of the process for preparing a hard disk or other storage medium for its first use. The disk formatting includes setting up an empty file system. A disk formatting may set up multiple file systems by formatting partitions for each file system. Disk formatting is also part of a process involving rebuilding an entire disk from scratch.

File Handling - In computer programming, a file descriptor is an abstract indicator for accessing a file. The term is generally used in POSIX operating systems. In Microsoft Windows terminology and in the context of the C standard I/O library, "file handle" is preferred, though the latter case is technically a different object (see below).Hardware Driver - A driver typically communicates with the device through the computer bus or communications subsystem to which the hardware connects. When a calling program invokes a routine in the driver, the driver issues commands to the device. Once the device sends data back to the driver, the driver may invoke routines in the original calling program. Drivers are hardware-dependent and operating-system-specific. They usually provide the interrupt handling required for any necessary asynchronous time-dependent hardware interface.

File Compression -
In computer science and information theory, data compression or source coding is the process of encoding information using fewer bits (or other information-bearing units) than an unencoded representation would use, through use of specific encoding schemes. As with any communication, compressed data communication only works when both the sender and receiver of the information understand the encoding scheme. For example, this text makes sense only if the receiver understands that it is intended to be interpreted as characters representing the English language. Similarly, compressed data can only be understood if the decoding method is known by the receiver.

Virus Checkers -
Antivirus (or anti-virus) software is used to prevent, detect, and remove malware, including computer viruses, worms, and trojan horses. Such programs may also prevent and remove adware, spyware, and other forms of malware. A variety of strategies are typically employed. Signature-based detection involves searching for known malicious patterns in executable code. However, it is possible for a user to be infected with new malware for which no signature exists yet. To counter such so-called zero-day threats, heuristics can be used. One type of heuristic approach, generic signatures, can identify new viruses or variants of existing viruses by looking for known malicious code (or slight variations of such code) in files. Some antivirus software can also predict what a file will do if opened/run by emulating it in a sandbox and analyzing what it does to see if it performs any malicious actions. If it does, this could mean the file is malicious.