(c) Garry Lancaster, 1999

of ZipUp)

This application allows you to create standard ZIP archive files on your Z88. Currently, only one level of compression is available: fast!

The following is the documentation for the program (also available in plain text format).


ZipUp allows you to compress and archive data files and programs on your Z88 using the common ZIP format. Files created by this program can be expanded using its companion application, Unzip. They can also be handled by compatible programs on other computers, such as PKWare's PKUNZIP or InfoZIP's Unzip.

There are many possible uses for the compressed archives that ZipUp produces. A single ZIP file is much easier to handle than multiple files, especially if you are trying to backup your Z88 to another computer using the Imp-Export popdown or similar software. Compression means that you can archive infrequently-used files, saving valuable RAM. Finally, the error-checking routines built in to ZIP files mean you can have confidence that any files transferred from your Z88 will arrive at their destination intact.

ZipUp interfaces properly with the Z88 operating system, so at any point when the application is waiting for input or a keypress, you may access the menu options, the help system or other applications. In particular, you can use the Filer to select a file to be zipped up.

The program requires an expanded Z88, using the same memory arrangement as BASIC.

Using the application

To create a ZIP archive, type its name at the prompt. If you don't specify an extension, the default of .zip will be used.

Next, you are presented with another prompt. Type in a filename to add to the archive, or select a file from the Filer. You may also use wildcards to add multiple files at once (eg use :ram.*//* to add every file in RAM to the archive).

The selected files will now be added to the archive, according to the options that have been chosen (see following section for details).

After adding the selected files to the archive, the prompt will re-appear, allowing you to add further files if you wish. When you have finished adding files, simply press ENTER at the prompt to finish creating the archive file.

Note that if for any reason you press ESC before the archive has been properly completed (or if any other error occurs), then an important part of the file (known as the central directory) will not be appended. This is vital for most unzip programs, although Z88 Unzip will usually be able to extract files even if it is missing.


During creation of an archive, the three options (shown on the window to the right of the screen) govern the behaviour of the program.

Each of these options can be cycled through their possible settings using the standard menu system (or the shortcut keys shown on the menu).


If you set this option off (the default), then files will be added to the archive and left in their original locations.

If you set this option on, then each file will be automatically deleted after adding it to the archive.

If you set this option to ask, you will be prompted whether you wish to delete each file: press Y (yes), N (no) or A (delete all files without asking again).


If you set this option off, then files are added to the archive without any attempt to compress them. This can increase the speed of operation considerably if you are archiving several incompressible files (such as other ZIP files, for example).

If you set this option on (the default), then files will be compressed before adding to the archive. Occasionally, files cannot be compressed - in this case they will simply be stored in the archive.


If you set this option off (the default), then only the names of files are included in the archive, with no information as to their original location.

If you set this option on, then the full path (excluding device name) of each file will be stored in the archive. This means that a full directory structure can be easily backed up with ZipUp, and later restored with Unzip.

The compression process

A file is added to the ZIP archive in two stages. In the first stage, the CRC checksum of the file is calculated. Then the program attempts to deflate the file - if this is not successful (resulting in a larger size than the original), then it is simply stored in the archive without compression.

During each stage, the progress meter at the bottom right of the screen indicates how much of the file has been processed so far. You can abort at any time by pressing ESC.


Initial release.

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