compressing files

compressing files

1. Working with online documents means that local fi les frequently need to be uploaded for sharing, or downloaded to be used for local processing.

2. Files may be extremely large, which can cause problems with transmission (delivery) in terms of speed and network usage. To reduce this problem, fi les have to be compressed (i.e. reduced in size) before transmission and then expanded after transmission. A common method of doing this is to convert them to zip fi les (.zip format)

3. Zip fi les are basically stores of data files which may have been compressed.

4. There are many different algorithms for doing the compression – with most compression software supporting several of these.

5. The last item in a zip fi le is an index, which shows the placement of each of the data fi les and allows other fi les to be added.

6. Quite often the zip fi le will also contain some program code (a sequence of instructions) to allow the fi les within the zip fi le to be unzipped (known as self-extracting fi les).

7. There is a wide range of software available for zipping fi les, with one of the most popular being WinZip

8. T he advantages of using online software The biggest advantage of using online document software is that you can allow many people to share a version of a document and work on it at the same time as other people (known as collaborative working). You can also access content: • anywhere there is an available internet connection • via different devices (e.g. PC, smartphone, tablet) • on different operating devices (e.g. Windows ® and Mac).

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