ZipUp v1.01
===========

(c) Garry Lancaster, 1999


Introduction
------------
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.


Options
-------
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).


Delete
------
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).


Compress
--------
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.


Paths
-----
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.


History
-------
v1.01	Bugfix: ZIP file could be added to itself with some 
	wildcards.
	Default extension of ".zip" now used if none given.
v1.00	Initial release.


Comments
--------
If you encounter any problems using the software, or you have any 
comments or suggestions, please contact me via the Z88 Forever! 
Website.

Garry Lancaster, 4th September 1999
