Compressing files

Compressing files

1. Working with online documents means that local files frequently have to be uploaded for sharing or downlooaded to be used for local processing

2. Files may be extremely large which can cause problems with transmission in terms of speed and network usage

3. To reduce this problem, files have to be compressed before transmission and then expanded after transmission

4. A common method of doing this is to convert them to zip files (.zip.format)

5. Zip files are basically stores of data files which may have been compressed

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

7. The last item in a zip file is an index, which shows the placement of each of the data files and allows files to be added

8. Quite often the zip file will also contain some program code (a sequence of instructions) to allow files within the zip to be unzipped (known as self-extracting files)

9. There is a wide range of software available for zipping files, with one of the most popular being WinZip