LPAK

	Brief documentation for LPAK 0.5(beta)
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				WARNING
				-------

This is a beta release meaning that it has not been widely tested on a
variety of systems.  If you find it doesn't work for you the most likely
reason is that your machine is more modern than mine and this software
is not yet aware of it.

The author cannot be held responsible for any damage that occurs to your
system as a result of using this software (although every effort has been
made to make it useful rather than harmful).

All I can say is that it works for me (but your mileage may vary).

Full sources (apart from the GENST2 libraries) have been provided so you
can see what it does and fix it if necessary.

			     END OF WARNING
			     --------------


What is LPAK?

	LPAK is a little utility that allows you to compress data files
	and will then decompress these files without user intervention
	whenever they are used.

	The user compresses selected files using the supplied packer
	(LZSS.PRG) and accesses them as normal when LPAK is installed
	and active.

	At present LPAK only works on data files - i.e. don't use it
	on program files (use a program packer on those instead).

	LPAK is meant to be helpful disk doubler (along the lines of
	stacker on the PC) - there is still some way to go towards that
	aim.


What will it do to my system?

	LPAK will install itself into the TRAP #1 vector chain and
	check each Fopen(...) call.  If the file being opened was
	compressed using LZSS.PRG (i.e. has a suitable header) then
	LPAK will decompress that file to a temporary file area
	(specified in LPAK.INF) and connect the user to that file
	instead on the compressed file.

	If you copy a compressed file it will be the decompressed
	version that gets copied (unless you deactivate LPAK by using
	the supplied desk accessory).

	It does some horrible stack fixing things which are the most likely
	to prevent it working on your computer (it was developed and tested on
	a 68000 based system which will differ from a 68020 or 68030 system
	for example).


Will I notice LPAK working?

	Yes and No.  All that will happen is that if you open a compressed
	file there will be a short delay while that file is decompressed
	to the temporary area.  Other than that you shouldn't notice the
	difference.


Installation:

	1) copy LPAK.PRG into the \AUTO folder on your boot disk

	2) copy LPAK.ACC and LPAK.INF into the root directory on
	   the same disk

	3) edit LPAK.INF so that it contains the path name of the area
	   where you want LPAK to store the temporary files.

	reset your machine - LPAK will hopefully now install itself into
	memory as your machine boots.

	It is recommended that you do not place LPAK into your hard disk
	auto folder until you are sure that it will boot correctly on your
	machine.  Test LPAK on a floppy disk first just to be sure (it may well
	save you a lot of trouble later).


Testing

	To see if your set-up works try reading the file LZSS.CMP in the test
	folder of this distribution.  If this file looks a lot like C code and
	in fact turns out to be exactly the same as LZSS.C once you have copied
	it to another directory then everthing works as well for you as it does
	for me.


BUGS

	At present you may need to tidy up the temporary area every now and
	then as any unclosed files or files that were left over from just
	before the machine was reset will not be destroyed (as far as I
	know - perhaps even I will be surprised).

	LPAK doesn't change the file size to show the size of the compressed
	file.  This may cause problems if you attempt to archive/zoo/lharc
	a compressed file while LPAK is active.  The archiver will probably
	get the file size and then read the file only to find the file is
	longer than it thought.  LPAK.ACC has been provided to allow
	you to turn off LPAK so that compressed files can be archived and
	copied without decompression occurring


Things waiting to happen

	Automatic Compression would be nice.

	Automatic tidy-up of the temporary area would also be nice.

	Knowing it works on a variety of systems would be really nice.


Other Information & Contacting the Author

	Written and tested on a 2.5Mb 520ST(M) flopy disk system in
	monochrome only using a 1Mb RAM disk to store LPAK temporary
	files (although disk A was tested as well).

	This software is not public domain (it remains the copyright of
	A.D.Webber) but you may use and distribute this as much as you like
	as long as no profit results from that distribution.  No distribution
	on a magazine coverdisk is allowed without the authors permission.
	(Not that you'd want to anyway as it might not work!).

	If you find any bugs, or have any comments, or you have improved the
	source code supplied in this distribution please let me know.


	Lloyd.

	otherwise known as:

	Andrew D. Webber,

	available via e-mail as: adw@ukc.ac.uk 
 

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