Applications and utilities

Overview

Recall questions on application software and utility programs, common utilities, defragmentation on hard disks and solid state drives, lossy and lossless compression, generic and bespoke software, and justifying applications for a given purpose.

What you need to know

Answer each one before you reveal it.

Questions from this subtopic

Each one with the model answer underneath.

1. 1

   What is application software?

   Model answer

   Software that carries out a task the end user actually wants done, rather than running or maintaining the computer itself - for example a word processor, a spreadsheet, a web browser, a database front end, a photo editor or a game. It relies on system software to reach the hardware.

2. 2

   What is a utility program?

   Model answer

   A small piece of system software that performs a specific maintenance, optimisation or housekeeping task on the computer, usually supplied with the operating system or added to it. Utilities keep the machine working well rather than doing work the user set out to do.

3. 3

   Name five utilities and say what each does.

   Model answer

   Any five of: a compression utility, which reduces file size for storage or transmission and restores it afterwards; a disk defragmenter, which rearranges the blocks of each file so they are contiguous on a magnetic disk, reducing head movement; antivirus or anti-malware software, which scans files and running processes against known signatures and suspicious behaviour and quarantines threats; a backup utility, which copies data to another medium on a schedule and can restore it; a file manager, which lets the user view, move, rename, copy and delete files and folders; encryption software, which scrambles files so they are unreadable without the key; and a disk clean-up utility, which deletes temporary and redundant files to reclaim space.

4. 4

   Why does defragmentation improve performance on a magnetic hard disk but not on a solid state drive?

   Model answer

   On a magnetic disk the read-write head must physically move to each fragment, and a file scattered across the platter costs many seeks; putting the blocks back together removes that movement. A solid state drive has no moving parts and reaches any block in the same time, so there is nothing to gain. Worse, defragmenting one causes a large number of unnecessary writes, and flash cells have a limited number of write cycles, so it shortens the drive's life.

5. 5

   Distinguish between lossy and lossless compression, and say which a compression utility for program files must use.

   Model answer

   Lossless compression encodes the data so that the original can be reconstructed exactly, bit for bit. Lossy compression discards information judged unimportant, so the restored file is only an approximation of the original. A compression utility handling program files, documents or spreadsheets must be lossless, because a single altered bit would break the program or corrupt the data; lossy compression is only acceptable for media such as images, audio and video where small losses of detail are tolerable.

6. 6

   Distinguish between generic (off-the-shelf) and bespoke (custom-written) application software.

   Model answer

   Generic software is written to be sold to many customers, so it is cheap per copy, available immediately, well tested by a large user base, and supported with documentation and training - but it may not do exactly what one organisation needs and may carry features it will never use. Bespoke software is commissioned for one organisation, so it fits their process exactly and can be changed on request, but it is expensive, takes a long time to develop, and starts with no user community, no third-party support and only the testing its developers did.

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