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_______ _______ _____________________ ___________

S L I M F i l e C o m p r e s s i o n S y s t e m
_______ _______ _____________________ ___________

U s e r M a n u a l

Version 1.01

SLIM User Manual V1.01 Copyright (C) Dominic Herity 1988. Pg 1

This software and manual are sold "as is" and without warranties
as to performance or merchantability. This software is sold
without any expressed or implied warranties whatsoever. No
warranty of fitness for a particular purpose is offered. Any
liability of seller or manufacturer will be limited exclusively
to product replacement or refund of the purchase price. Dominic
Herity1further reserves the right to alter the specifications of
the software and contents of the manual without obligation to
notify any person or organization of such alterations.

SLIM User Manual V1.01 Copyright (C) Dominic Herity 1988. Pg 2

A U T H O R ' S N O T E

SLIM was born from a conviction that there has to be a better
way. A better way to store data and a better way to get at it
once it is stored. It was nurtured by hours of frustration trying
to cram all the files I needed onto my disk, while at the same
time knowing that the files I was struggling with were larger
than necessary.

I went with confidence to the marketplace, looking for a package
that would reduce my files. But I was disappointed with what I
found there. One package offered good compression with the major
hang-up that compressed files are stored in an archive and that
you have to manually take them out before using them. Good for
backup, but little else. Other packages promised wonders in
glossy advertisements, transparent access among them. Sadly,
though they delivered transparent access, they were lousy at
compression, concerning themselves with such specialties as
English text or spreadsheets in a particular format.

I was also disappointed by the algorithms in available packages.
They were too inflexible. They looked for patterns that were too
restrictive to cover the types of files found on most PCs. So I
devised my own algorithm and found to my surprise that it
compressed files I did not expect to compress and that it
compressed English text and spreadsheets better than English text
and spreadsheet compressors (not bad, considering that it doesn't
know a thing about English or spreadsheets).

So I had at last found a package that would do worthwhile
compression on lots of computer files. But it only existed in my
head. So an interesting experiment became a development project.
Thousands of solitary hours were spent at this keyboard, hours of
frustration and elation, boredom and excitement, doubt and
conviction.

Many thanks to Brian Doody, Kevin McGoldrick, Imelda Herity and
Michael Feehily, each of whom contributed to this product.

Now it is finished, at least for now. It works, it works well
and it does all I hoped it would do. It could do more ... But I
must submit to judgment. You, the user, must decide if my time
has been well spent. The product is before you and I believe that
it will be of considerable use to you. Your registration is your
vote of confidence in this work and your reservation of future
upgrades, which should not be long in coming.

Dominic Herity
27th November 1988

SLIM User Manual V1.01 Copyright (C) Dominic Herity 1988. Pg 3

C O N T E N T S

Section Subject Page

1.0 Introduction 4

2.0 Getting Started 5

3.0 Compressing Files 8

4.0 Accessing Compressed Files 12

5.0 De-compressing Files 15

6.0 Files used by SLIM 16

7.0 Error and other Messages 17

8.0 Version History 19

9.0 Registration 20

SLIM User Manual V1.01 Copyright (C) Dominic Herity 1988. Pg 4

1.0 I N T R O D U C T I O N

SLIM is a powerful file compressor with RAM resident transparent
expander, which gives painless access to compressed files. This
is done by intercepting file access DOS calls, allowing
applications to read compressed files just as before. Effective
doubling of disk space is common, without worrying about
technicalities like archives. Just put a command to load SLIM
into the AUTOEXEC.BAT file and forget it.

A powerful proprietary compression algorithm yields a compression
ratio substantially better than commercial file compressors,
without depending on restricted file types. SLIM replaces several
products which compress a limited range of data types, like
spreadsheets in a particular format or English text. Compression
depends on file type and contents, but files are typically
compressed to about the following percentages of original size.
Word processing documents : 50% (including non-English),
Spreadsheets : 30%, database : 20%, program source code 50%, COM
and EXE files 75%.

Also included is a report facility to see which of a group of
files are compressed, by how much and with what total savings.

Compressed files have checksums to protect against corruption.
SLIM's compact size (less than 32KB) makes it practical for
floppy as well as hard disk machines. The shareware version of
SLIM won't compress files over 64KB, but an unlimited version is
received on registration.

The RAM resident part of SLIM uses 72KB of main memory.

System Requirements: IBM PC or MSDOS machine, MSDOS Ver 2.00+,
256K+ RAM

SLIM User Manual V1.01 Copyright (C) Dominic Herity 1988. Pg 5

2.0 G E T T I N G S T A R T E D

To get SLIM up and running, you need only one file, SLIM.EXE.
This contains all the functions of a working system. Copy
SLIM.EXE from your distribution diskette onto your hard disk. The
root directory is recommended.

C>COPY A:SLIM.EXE

If you do not have a hard disk, copy SLIM.EXE onto any system
(boot) disks you will use to boot your machine before accessing
compressed files. It is not necessary to have SLIM.EXE on all
disks with compressed files, if you only need to read the files.

If your system disk has a file AUTOEXEC.BAT, add a line to the
file, with the text : "SLIM ON". This ensures that every time
your computer is powered on, compressed files can be accessed
normally. If you do not have a file AUTOEXEC.BAT, create one with
the same line.

C>TYPE AUTOEXEC.BAT
SLIM ON
C>

Re-boot your system (Ctrl-Alt-Del). The following message will
appear when AUTOEXEC.BAT runs.

C>SLIM ON
S L I M F i l e C o m p r e s s i o n S y s t e m V1.01

Loading SLIM de-compressor
C>

This indicates that the RAM resident part of SLIM is now loaded.
This is needed to allow you to access compressed files. It is
also needed to de-compress compressed files (see section 5). As
SLIM now occupies 72KB of RAM which was previously available for
programs, some larger programs may not run with SLIM loaded. This
is more of a problem with systems containing 256K RAM, but if
your machine has 512K or more, you should have no difficulty.

Now your system is ready to handle compressed files. All you have
to do now is compress some, and start saving disk space (or
expanding your disk, if you prefer to see it that way).

SLIM User Manual V1.01 Copyright (C) Dominic Herity 1988. Pg 6

Pick one or more files for compression. As this is a
familiarization exercise, take a small one (say, between 5000 and
30000 bytes), since compressing large files takes a lot of time.
The file selected should also be one that you read often, but
write to seldom or never. An EXE or COM file is a good candidate
on this basis, but these don't compress as well as text or
program source code. Spreadsheets and database files compress
best, but they tend to be too large for our present purposes.
DON'T select a file that you need before SLIM is turned on, e.g.
COMMAND.COM or SLIM.EXE, as SLIM will refuse to compress these.
(See section 3 for more details.) Also, ensure that you have at
least twice as many bytes free on your disk as the file you wish
to compress, because SLIM needs workspace to compress a file.

Let's assume you chose to compress the DOS utility program
FIND.EXE. (I suggest this because it gives unusually good results,
at least in PC-DOS Version 3.00.) Type :

C>SLIM FIND.EXE

SLIM displays a byte counter when compressing the file and
reports the saving when it is finished.

C>SLIM FIND.EXE

S L I M F i l e C o m p r e s s i o n S y s t e m V1.01

Original Compressed Save
Bytes Bytes (%) File (Press any key to abort)

6363 1019 83% C:FIND.EXE

6363 bytes reduced to 1019 in 1 files saving 5344 (83%)

360448 bytes free out of 20971520. SLIM is RESIDENT and ACTIVE.

In the unlikely event that SLIM cannot compress the file, pick
another one. Most files are compressible.

So you have liberated some disk space from FIND.EXE. Now try to
use the compressed file.

C>FIND "SLIM" <AUTOEXEC.BAT
SLIM ON
C>

As you can see, FIND.EXE works just as before. SLIM works on all
sorts of files just as easily, word processor documents,
spreadsheets, ASCII files, and peculiar unique files used by
various software packages.

SLIM User Manual V1.01 Copyright (C) Dominic Herity 1988. Pg 7

To see if a file or set of files is compressed, and by how much,
use the SLIM R command. For example :

C>SLIM R DOS\*.*

S L I M F i l e C o m p r e s s i o n S y s t e m V1.01

Original Compressed Save
Bytes Bytes (%) File (Press any key to abort)

6363 1019 83% DOS\FIND.EXE
8544 4044 52% DOS\SHARE.EXE
15123 9882 34% DOS\ATTRIB.EXE
3629 2539 30% DOS\SYS.COM

33659 bytes reduced to 17484 in 4 files saving 16175 (48%)

96256 bytes free out of 20971520. SLIM is RESIDENT and ACTIVE.

But before you get carried away, glance through the rest of this
manual. You could read it while SLIM crunches up some of those
monstrous files that have been hogging your disk.

SLIM User Manual V1.01 Copyright (C) Dominic Herity 1988. Pg 8

3.0 C O M P R E S S I N G F I L E S

3.1 BASIC OPERATION
_______________

Before files can be compressed, SLIM must have been loaded by the
SLIM ON command. This is because the compression process performs
a check using the RAM resident de-compressor, to guard against
internal bugs which might prevent later access to a compressed
file.

Files can be compressed by entering :

C>SLIM [n] filespec

where 'filespec' is a filename including optional path. More than
one file can be compressed if wildcards ('*' or '?') are included
in the filespec. SLIM will take each file matching the filespec
and attempt to compress it. '[n]' is an optional number 0 to 9
which alters the 'thoroughness' of the attempt to compress the
file(s). This will not normally be used, but see section 3.3
below for more information.

As SLIM compresses each file, it displays a byte count indicating
the progress of compression. If you want SLIM to skip a file,
press any key and SLIM will abandon the file on the next counter
update and proceed to the next file.

When a file has been compressed, the original and compressed
sizes are displayed on screen, as in the SLIM R command.

If SLIM encounters a file which is already compressed, it will
bypass it.

When all files have been processed, SLIM displays a summary of
bytes saved and total bytes and bytes free on the disk. See
example below.

C>SLIM DOS\*.*

S L I M F i l e C o m p r e s s i o n S y s t e m V1.01

Original Compressed Save
Bytes Bytes (%) File (Press any key to abort)

6363 1019 83% DOS\FIND.EXE
8544 4044 52% DOS\SHARE.EXE
15123 9882 34% DOS\ATTRIB.EXE
3629 2539 30% DOS\SYS.COM

33659 bytes reduced to 17484 in 4 files saving 16175 (48%)

96256 bytes free out of 20971520. SLIM is RESIDENT and ACTIVE.

SLIM User Manual V1.01 Copyright (C) Dominic Herity 1988. Pg 9

3.2 DISK SPACE REQUIRED
___________________

SLIM needs some workspace on disk to compress files. When
compressing, it reads the original file and writes to a temporary
file. It then reads the temporary file and produces the
compressed file, before deleting the original file and temporary
file. To do all this, SLIM needs up to twice as much free disk
space as the largest file to be compressed. If SLIM runs out of
disk space while compressing a file, it will output an error
message, leave the file uncompressed and proceed to the next
file. If you are short of free disk space and wish to compress a
number of files, some small and some large, compressing the small
files first may free enough disk space to allow the large files
to be compressed.

3.3 COMPRESSION THOROUGHNESS
________________________

When compressing files, SLIM can be instructed to 'try harder' or
'hurry up' by specifying a compression thoroughness parameter.
This is done by inserting a number between 0 and 9 before the
filespec. For example :

C>SLIM 7 *.EXE

will compress all .EXE files in the current directory with a
thoroughness parameter of 7. The parameter defaults to 5 if not
specified. A higher value means a longer runtime and (possibly)
better compression performance. A lower value means shorter
runtime and (possibly) worse compression. These results are not
guaranteed, however, and it may happen that a file compressed
with a parameter of 6 is actually larger than one compressed with
a parameter of 5. In addition for larger parameter values,
runtime tends to double for each increment in parameter value,
with little or no improvement in compression. For these reasons,
it is usually best to leave this parameter alone. It should be
reserved for when you badly need better compression on a
particular file, or use a low value to quickly squash a few files
to give you some temporary disk space.

3.4 INCOMPRESSIBLE FILES
____________________

Occasionally, SLIM will encounter a file whose 'compressed'
size is actually larger than the original. When this happens,
SLIM leaves the file uncompressed and outputs a message saying
that it cannot compress the file.

SLIM User Manual V1.01 Copyright (C) Dominic Herity 1988. Pg 10

3.5 RUNTIME
_______

File compression take a long time compared to the small delay on
access. On an original IBM PC/XT, compressing 20MB of files could
take two days! Of course, most machines today are at least 66%
faster and some are 10 to 20 times faster. But compressing
megabytes is still something to be done when the machine is idle,
rather than when you are using it. Fortunately, compression is
largely a once off task and only needs to be repeated when new
files are added to the disk or when files have been written to.

A further consequence of the long compression runtime is that
files which are frequently written to should not be compressed.
The short term gain of disk space is outweighed by the time taken
to re-compress the file and the inconveniencd∩╧Ç╧╧╧äÇÇéêO≡p╧╧╧╧╧╧╧╧îäê╧Çüê└≡p≡p╧╧╧╧╧╧╧╧æÄrge quantities of files can be compressed overnight using a
batch file. If the batch file is still running when you need the
machine again, it can be safely interrupted by pressing Ctrl-
Break. The batch file can be re-started later and SLIM will
quickly skip over files already compressed. Here are some example
batch files for compressing large numbers of files.

C>TYPE SLIM1.BAT
REM COMPRESS ALL FILES IN WS DIRECTORY
C:\SLIM C:\WS\*.*

C>TYPE SLIM2.BAT
REM COMPRESS ALL FILES IN :
REM WS, WS\DATA, SYMPH, SYMPH\DATA, DBASE, DOS ETC.
C:\SLIM \WS\*.*
C:\SLIM \WS\DATA\*.*
C:\SLIM \SYMPH\*.*
C:\SLIM \SYMPH\DATA\*.*
C:\SLIM \WS\*.*
C:\SLIM \DBASE\*.*
C:\SLIM \DOS\*.*
C:\SLIM \XTREE\*.*

C>TYPE SLIM3.BAT
REM COMPRESS ALL FILES IN :
REM WS, WS\DATA, SYMPH, SYMPH\DATA, ETC.
FOR %%X IN ( WS WS\DATA SYMPH ) DO C:\SLIM \%%X\*.*
FOR %%X IN ( SYMPH\DATA DBASE DOS XTREE ) DO C:\SLIM \%%X\*.*

The last of these examples is the most useful. By customizing
SLIM3.BAT to your own machine's directory structure, you can
compress all the files in some or all of your directories. The
batch file can be re-run at intervals to catch any new or
rewritten files. When you change your directory structure, edit
the batch file accordingly.

SLIM User Manual V1.01 Copyright (C) Dominic Herity 1988. Pg 11

3.6 FORBIDDEN FILES
_______________

Compressed files can only be correctly read when SLIM is
activated, using the SLIM ON command. This command would
typically be in the AUTOEXEC.BAT file. However, certain files
must be read before SLIM is activated. Examples are COMMAND.COM,
CONFIG.SYS and of course, SLIM.EXE. If any of these files were
compressed, the computer could not power up properly. For this
reason, SLIM will refuse to compress any files with a ".SYS"
extension and any files called COMMAND.COM, IBMBIO.COM,
IBMDOS.COM, AUTOEXEC.BAT or SLIM.EXE. When SLIM encounters any of
these files during compression, it leaves it uncompressed and
outputs a message saying the file should not be compressed.

SLIM User Manual V1.01 Copyright (C) Dominic Herity 1988. Pg 12

4.0 A C C E S S I N G C O M P R E S S E D F I L E S

4.1 CONFIGURING YOUR SYSTEM WITH SLIM
_________________________________

To ensure access to compressed files, enter the command 'SLIM ON'
in your AUTOEXEC.BAT file. Make sure that this command occurs
before any commands that access compressed files. For example, if
you compress SK.COM, and you have the command SK in AUTOEXEC.BAT,
you must place the 'SLIM ON' command before the 'SK' command.

If you do not wish to have SLIM permanently loaded, which may be
the case if you have an application that needs lots of memory,
make sure to enter the SLIM ON command before attempting access
to any compressed files. Once SLIM is loaded into memory by the
SLIM ON command, it cannot be removed, except by restarting your
computer (Ctrl-Alt-Del).

4.2 HOW COMPRESSED FILES ARE ACCESSED
_________________________________

Once loaded, SLIM gives automatic access on demand to compressed
files. It does this by intercepting any calls a program
(including COMMAND.COM) makes to DOS. Normally, SLIM passes these
calls straight on to DOS, but when a call is detected which opens
a compressed file, SLIM reads the file and makes a full size copy
on disk for the program to use. It then changes the name of the
compressed file to a name it recognizes itself and renames the
new full size file to the original file name. Only then does it
pass the call on to DOS. Neither DOS nor the program know that
this is happening, so operation is completely automatic. When an
expanded file is closed without being modified, SLIM (equally
quietly) deletes the expanded copy and renames the original
compressed file to its original name. If a program modifies an
expanded copy of a file, SLIM deletes the compressed original and
leaves the expanded new file on disk.

Compressed files may be renamed without affecting access.
Compressed files can also be deleted. If a compressed file is
copied to another file with SLIM ON, the new file will be a full
size, not a compressed, copy of the original.

4.3 COPYING AND BACKING UP COMPRESSED FILES
_______________________________________

In some circumstances, you may wish to manipulate files without
expanding them. Copying and backing up files are such
circumstances. The command SLIM OFF is provided for this reason.
It prevents SLIM from expanding files when opened, but does not
remove SLIM from memory or prevent it expanding a COM or EXE file
when it is run.

SLIM User Manual V1.01 Copyright (C) Dominic Herity 1988. Pg 13

Do not forget to turn SLIM ON again when the copying or backup is
complete. If in doubt, an extra SLIM ON command will not hurt. To
see if SLIM is ON or OFF enter the command SLIM and the status
will displayed, INACTIVE meaning OFF and ACTIVE meaning ON.

If you mistakenly access a file with SLIM OFF or not loaded, the
file will not make sense, but the error will be obvious. Most
programs report in a fairly civilized manner when a file is not
what they expect. If the compressed file is accessed as an ASCII
or text file, the file will seem to contain the message '= sLiM'
and nothing else. If a program in a compressed COM file is
mistakenly run without SLIM loaded, the program will stop
immediately.

4.4 DISK SPACE
__________

Because SLIM makes a full size copy of each file that is
accessed, there must be enough disk space free to accommodate all
the full size copies that will be need at any one time. This does
not, however, include full size copies of COM or EXE files that
are being run, as these are deleted immediately when their
contents are loaded into memory.

This can be illustrated by the following example.

C>SLIM R *.*

S L I M F i l e C o m p r e s s i o n S y s t e m V1.01

Original Compressed Save
Bytes Bytes (%) File

46080 39720 13% WSOVLY1.OVR
25600 19563 23% WS.COM
32256 18004 44% WSMSGS.OVR
19840 8473 57% DOCUMENT.TXT

123776 bytes reduced to 85760 in 4 files saving 38016 (30%)

106596 bytes free out of 20971520. SLIM is RESIDENT and ACTIVE.

I will run WS.COM (a well known word processor) to edit the file
DOCUMENT.TXT. The files WS.COM, WSOVLY1.OVR and WSMSGS.OVR are
compressed, as is DOCUMENT.TXT. WS.COM uses data in WSOVLY1.OVR
and WSMSGS.OVR, so it accesses these. So my disk must have at
least 46080 + 32256 + 19840 = 98176 bytes free. (More accurately,
it must have 48K + 32K + 20K = 100K bytes free, since data is
stored on the disk in units no smaller then 2K.) I don't need
25600 bytes for WS.COM as this is only expanded transiently,
until loaded into memory. But I do need to have 25600 bytes free
just to run WS.COM.

SLIM User Manual V1.01 Copyright (C) Dominic Herity 1988. Pg 14

Don't panic! You do NOT need a calculator to use SLIM. The above
information is provided so that you will know (a) what is
happening, if it happens, and (b) what must be done to stop it
happening. If you prefer, do what you did last time you ran out
of disk space - start deleting files.

When SLIM runs out of disk space on expansion, it returns an
'Access denied' error as a response to the DOS call, but the
message on screen may not make this obvious. For example, if you
try to execute a compressed .EXE file, and SLIM fails to expand
it, the message that appears on screen is 'Bad command or file
name'.

Do not put a write protect tab on a floppy disk if you want to
access compressed files on that disk, as this prevents generation
of an expanded copy. This is not a problem, however, if you only
use the disk for file storage. The file may be copied from the
write protected disk with SLIM turned OFF, and then accessed on
an unprotected disk, with SLIM turned ON.

SLIM User Manual V1.01 Copyright (C) Dominic Herity 1988. Pg 15

5.0 D E - C O M P R E S S I N G F I L E S

5.1 BASIC OPERATION
_______________

The SLIM X (eXpand) command de-compresses a file or set of files.
This command can only be used if SLIM has been made RAM resident
with the SLIM ON command. Example :

C>SLIM X DOCUMENT.TXT

S L I M F i l e C o m p r e s s i o n S y s t e m V1.01

Original Compressed Save
Bytes Bytes (%) File

19840 8473 57% DOCUMENT.TXT

19840 bytes were reduced to 8473 in 1 files saving 11367 (57%)

83968 bytes free out of 20971520. SLIM is RESIDENT and INACTIVE.

5.2 DISK SPACE REQUIRED
___________________

For SLIM X to execute correctly, enough free disk space must be
available to store an expanded file as well as the compressed
file, because the compressed file is only deleted after the de-
compressed file is produced.

SLIM User Manual V1.01 Copyright (C) Dominic Herity 1988. Pg 16

6.0 F I L E S U S E D B Y S L I M

Using SLIM, you will occasionally glimpse files with strange
names lurking on your disk. SLIM uses files called
'SLIMTMP0.$$$', 'SLIMTMP1.$$$' and 'SLIMnnnn.TMP' where nnnn is a
four digit decimal number. The first two of these should be
deleted if seen, as they are evidence of power loss or other
disaster during file compression. The other files are the
compressed originals of open files (See Section 4.2). These will
be seen if, for example, you call up a directory display in a
word processor whose working files are compressed.

If you see any files of the type 'SLIMnnnn.TMP' when you are SURE
that you do not have any compressed files open (for example, on
power up), this indicates power loss or other failure when the
file was being accessed. Rename the file to something else (e.g.
WHATISIT.FOR) and use the SLIM R command to see the original file
size. If that size is the same as that of another file in the
same directory, then WHATISIT.FOR is probably the compressed
original of that file. If you are sure that WHATISIT.FOR is not
an older version of a revised file, rename it to the filename of
your choice and continue to use it. Otherwise, delete it.

SLIM User Manual V1.01 Copyright (C) Dominic Herity 1988. Pg 17

7.0 E R R O R A N D O T H E R M E S S A G E S

There follows an alphabetically sorted list of error messages
produced by SLIM, with (as appropriate) some information on
probable cause and references to this manual for further
information.

MESSAGE : aborted
CONTEXT : After failed compression of a file
CAUSE : User hit a key, abandoning compression
FURTHER INFORMATION : Section 3.1

MESSAGE : Can't compress this file
CONTEXT : After failed compression of a file
CAUSE : File size can't be reduced
FURTHER INFORMATION : Section 3.4

MESSAGE : Can't expand this file
CONTEXT : Failed expansion of compressed file
CAUSE : Not enough free disk space to make expanded copy.
FURTHER INFORMATION :

MESSAGE : Can't open (filename)
CONTEXT : During compression, expansion or reporting
CAUSE : File was found but could not be opened.
FURTHER INFORMATION :

MESSAGE : Can't open new file
CONTEXT : At start of file compression
CAUSE : Full disk or directory
FURTHER INFORMATION : Section 3.2

MESSAGE : Can't open temporary
CONTEXT : At start of file compression
CAUSE : Full disk or directory
FURTHER INFORMATION : Section 3.2

MESSAGE : Can't write to output file
CONTEXT : During file compression
CAUSE : Disk full
FURTHER INFORMATION : Section 3.2

MESSAGE : Insufficient Memory
CONTEXT : At SLIM startup
CAUSE : Not enough memory available for SLIM to run
FURTHER INFORMATION : Section 1

MESSAGE : Internal Error : Can't compress this file
CONTEXT : At end of file compression
CAUSE : SLIM internal error. Should not occur
FURTHER INFORMATION : Contact the author

MESSAGE : Loading SLIM de-compressor
FURTHER INFORMATION : Section 4.1

SLIM User Manual V1.01 Copyright (C) Dominic Herity 1988. Pg 18

MESSAGE : No files
CONTEXT : At SLIM startup, compressing, expanding
or reporting on files.
CAUSE : No files were specified for processing.
FURTHER INFORMATION : Section 2.0, 3.1, 5.1

MESSAGE : Should not compress this file
CONTEXT : At start of file compression.
CAUSE : SLIM refuses to compress file.
FURTHER INFORMATION : Section 3.6

MESSAGE : SLIM de-compressor already off
FURTHER INFORMATION : Section 4.3

MESSAGE : SLIM de-compressor already on
FURTHER INFORMATION : Section 3.1, 4.3

MESSAGE : SLIM de-compressor not loaded
FURTHER INFORMATION : Section 4.3

MESSAGE : SLIM de-compressor turned off.
FURTHER INFORMATION : Section 4.3

MESSAGE : SLIM de-compressor turned on
FURTHER INFORMATION : Section 3.1, 4.3

MESSAGE : SLIM must be loaded to do compression or expansion.
CONTEXT : Attempt to expand or compress files.
CAUSE : For these commands to be used, it is necessary for
SLIM to be resident first. (SLIM ON command.)
FURTHER INFORMATION : Sections 3.1, 5.1

MESSAGE : PC-DOS or MS-DOS Version 2.00 or greater required
CONTEXT : SLIM startup.
CAUSE : You are using an old version of DOS (Ver1.xx).
FURTHER INFORMATION : Section 1

MESSAGE : Write error on output
CONTEXT : After file compression.
CAUSE : Disk full.
FURTHER INFORMATION : Section 3.1

MESSAGE : Write error on temporary
CONTEXT : After file compression.
CAUSE : Disk full
FURTHER INFORMATION : Section 3.1

8.0 V E R S I O N H I S T O R Y

Version : 1.00 Released : November 1988

This is the initial release of SLIM.

Version : 1.01 Released : April 1989

The shareware version previously demonstrated compressibility of
files larger than 64K. Since this can be time-consuming, large
files are now skipped over. Licenced version behaves as before.

9.0 R E G I S T R A T I O N

9.1 THE PITCH
_________

Legitimate readers of PC PLUS may use this version of SLIM for
non-commercial purposes without obligation. If you intend to use
it commercially, however, you are morally obliged to register
with the author. Registration of SLIM will entitle you to :

* A licensed copy of the current version which compresses
files of unlimited size (See sections 1,3)

* A printed W▄ƒ ƒαßαßƒƒƒƒƒƒƒƒƒƒƒƒƒüƒ<ƒrt from the author

* Notification of future upgrades

* The chance to order these upgrades at a large discount

SLIM is at the beginning of its life. Even while developing this
initial release, I have envisaged improvements in compression, in
speed and in features offered, some with major potential.
However, these improvements will take time and money to achieve.
So if you believe that SLIM enhances your computer, or if you
want the latest update handling files of unlimited size, or if
you would like first refusal of future enhancements at a special
price, please register now. The next page contains an order form
and optional questionnaire which you should print out, fill in
and mail to me.

I rely on your support.

9.2 SLIM ORDER FORM
_______________

(PLEASE USE BLOCK CAPITALS)

Title (Mr/Ms) : ____

Surname : __________________

Christian Name : __________________

Company : __________________
(Please include if licence required for company, rather than
personal use.)

Address : _________________________________________

_________________________________________

Number of licenced copies of SLIM required at $45.00 each : ____

Method of payment (please tick one) :

Access/Mastercard____ American Express____

Cheque____ Bank Draft____

If payment by Access or American Express, please supply following
information :

Card number____________________ Expiry Date______________

Each copy includes a printed manual and 5.25 inch floppy disk
containing a licenced, full function copy of SLIM. Charge per
copy is 45 U.S. dollars or equivalent. This includes registration
and upgrade fees, materials, postage and packing. Unless payment
is by credit card, please enclose a cheque or US dollar bank
draft for the required amount. If you send a cheque in a currency
other than US dollars, please allow for exchange rate variation
and for the difference in bank buying and selling rates. An order
may not be filled if payment offered falls short.
This order should be sent to :
Mr Dominic Herity, Dunfore, Ballinfull, Co. Sligo, Ireland.

Cheques and bank drafts should be crossed and made payable to :
Mr Dominic Herity

Thank you. Please see questionnaire on next page.

9.3 QUESTIONNAIRE
_____________

This questionnaire is entirely optional. You may ignore it or
fill it in partially or fully and return it with your order. But
I would be obliged if you would take a few minutes over it to
help me improve SLIM to meet your needs better.

9.3.1 YOU
What is your profession ? ___________________

How often do you use your computer ? (Please tick one)

Occasionally____ Daily____ Much of time____

9.3.2 YOUR COMPUTER
Manufacturer ___________________ Model ___________________
CPU (Circle one) 8088 8086 80286 80386 V20 V30
Other (please specify) ___________________

Speed(MHz) ___________________ RAM(KB) ___________________

Hard Disk Capacity (MB) ___________________

Floppy drives : Number ____ Capacity (KB) ____
Form Factor (Circle one) 5.25" 3.5"

9.3.3 YOUR APPLICATION
What do you mainly use your computer for ?
(Circle one or more) Word processing Spreadsheets CAD
Database Accounts Software Dev't Desktop Publishing
Games Other (please specify) ___________________

List the software packages that you use most often

1 ___________________ 4 ___________________

2 ___________________ 5 ___________________

3 ___________________ 6 ___________________

9.3.4 YOUR USE OF SLIM
How did you acquire your shareware copy of SLIM ?
e.g. friend, shareware company (please specify)

___________________

Approximately how much disk space do you expect to save ?

___________________bytes reduced to ___________________

What types of files do you expect to make the savings on ?
(Circle one or more) Word processor ASCII text
EXE and COM files Database Spreadsheets Graphics

Other (please specify) ___________________

Approximately what range of file sizes do you wish to
compress ?
From ___________________ to ___________________ bytes

Please rank these potential improvements for SLIM in your
order of choice

__ Faster compression

__ Faster expansion/access

__ Automatic re-compression of files written to

__ More compression/smaller compressed files

__ Less disk workspace used by SLIM when compressed
files are being accessed.

__ Other (please specify) ___________________

How do you rate this manual (Circle one)
Very Bad Bad Fair Good Excellent

Please Indicate any parts of this manual which are unclear
or difficult :

__________________________________________________________

Has SLIM enabled you to postpone or cancel upgrading your
hard disk ? (Circle one) Yes No

Please list any other file compression utilities you know,
whether you have used them, and any comments you have on
them.

__________________________________________________________

9.3.5 YOUR COMMENTS
Any suggestions for product improvement, complaints about
shortcomings, etc. would be much appreciated, however
small you may consider them. Attach a separate sheet if
necessary.

__________________________________________________________