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CHMELEON.TXT
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1991-03-29
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The Chameleon Vers. 1.19
---------------------------
Karsten Isakovic
Wilmersdorferstr.82
D-1000 Berlin 12
Federal Republic of Germany
published at Markt&Technik-Verlag,
all rights by the author
Everybody knows the following problems:
---------------------------------------
- There are many, many useful DA, but one can't install them
all some at the same time. To install a new DA, you have to
reboot the system. This is the reason, why the MultiDAs came
up. They allowed to install more DAs than six. And there are
some MonsterDAs that give you everything you ever could need
under just one menu entry. These solutions often need lots
of memory, which is a rare on normal STs.
- If you programm DAs it is very bad that you have to reboot
for every test. This costs time and nerves.
Now there is a new solution to this problem:
--------------------------------------------
The CHAMELEON is an extrem short DA - about 5 KB -, that
allows to load in every DA you need and - that's the clue
of the Chameleon - can unload DA if you don't need it
any more. Not only the main memory is freed, the Chameleon
frees all resources the DA demanded from the system.
Usage
-----
Copy the CHMELEON.ACC onto the boot disc and reboot. If you
choose 'The Chameleon' from the DA-menu a file selector
appears and you can select the DA, which is then loaded and
started.
If you don't want to open the DA, hold down the left shift-
key, while selecting the name in the file selector by double-
clicking or while pressing the return key.
After the DA is started, the Chameleon menu entry is replaced
by the menu entry of the DA. An arrow on the left side of the
enty shows that this DA was loaded with 'The Chameleon'.
If the DA normaly uses 2 menu entrys the menu text is split
in the middle. The right entry is selcted if you hold down
one of the shift keys while selecting the menu entry. If the
DA normaly uses 3 menu entrys you can select the middle entry
with the left shift key and the right entry with the right
shift key.
Now you can use the DA, as if it was loaded after a reboot.
If you want to remove the DA, just hold down the shift and
alternate keys and select the menu entry. If the DA had
opened some windows, these are closed. All memory the DA
demanded is freed up and the normal 'The Chameleon' menu
entry appears in the DA menu.
If you want to remove the DA and immediatly load another DA,
hold down the right mouse button in addition to the shift and
alternate key while selecting the menu entry.After the DA is
unloaded, the file selector comes up.
Installation for GEMINI users:
------------------------------
Test with 'env' in the MUPFEL, whether the SUFFIX contains
'acc'. If not insert it with 'setenv SUFFIX "$SUFFIX;acc" '.
The best way to do this is in the file MUPFEL.MUP.
Now you can select the CHMELEON.ACC an install it as default-
application for '*.AC?'.
The next step is to rename all other DAs to ACX, because with
the SUFFIX '*.ACC', GEMINI only test whether the DA is already
laoded. If you double click onto a file with the SUFFIX '*.ACX',
'The Chameleon' gets a message from GEMINI. The Chameleon loads
the selected DA and opens it. If there was already an DA loaded,
this DA is removed first.
If you put a 'The Chameleon' icon onto the desktop of GEMINI,
you can drag DA onto the icon to load them in. If you drag
a text file onto the icon, this GEMINI message is passed to
to loaded DA.
If the DA has also an icon on the desktop, you can load the
DA by dragging the DA icon onto the Chameleon icon.
If the DA receives GEMINI messages, it does not matter whether
you drag text files onto the icon of the DA or onto the
Chameleon icon.
Default-DA:
-----------
Another speciality hides in the patch variables of Chameleon.
You can specify a default-DA that is loaded in at boot time.
So you can set up your normal configuration without loosing
the flexibility 'The Chameleon' offers to you.
The default is the ATARI control panel with the file name
CONTROL.ACX on the boot device. All preferences are set up
by the control panel. If you need another DA, just unload the
control panel and load the other DA.
Patch variables:
----------------
First: Make a copy of CHMELEON.ACC, bevor starting to
experiment! You can only change the patch variables with a
disc monitor.
It is very likely that there are collisions with the shift codes
that Chameleon uses, so you can change the combination.
Right bevor the string 'V1.19 ©K.Isakovic Berlin 09.10.90' you
find a '^', which is the delimiter between the patch variables.
It marks the longest possible space that you have to enter
path names, you should not overwrite it.
The first 2 bytes ($0A $02) in front of the ^ are the
shift combinations. The first bytes ($0A) is the combination
to remove an DA, the second ($02) is the combiantion that
tells Chameleon not to open up the DA, when you load it in.
If you set this value to $00, the DA is not opened up
automaticly, only if you press a shift key.
These values are the hexadecimal value of the sum out of the
following table:
value | key
------+--------
1 | right shift
2 | left shift
4 | control
8 | alternate
The bytes $0A stand for the value 10, which stands for left
shift - alternate.
In front of this two shift combinations you find the name of
the default DA. If the first byte after the '^' is $00 (default),
no DA is loaded in. Enter the absolute pathname of the DA
(i.e. A:\CONTROL.ACX, the drive specification is neccessary!).
If the drive 'A:\' is automaticly replaced with the boot drive.
If there is another dive letter than 'A', no modification takes
place. Don't forget to end the name with a NULL ($00) !
In front of this you find yet another field seperated with
a '^'. In this field you can fill in the path, that is used
if you first select a DA in the file selctor. This feature
is very good, if all the DAs reside in a sub directory. The
drive letter is modified (or not) in the same manner as for the
dafault DA.
The last patch variable is a byte value that tells the file
handle that Chameleon uses for output redirection. The value
$00 means no redirection at all. On the ST there is no NULL-
device that takes all input and does nothing, so Chameleon
redirects STDOUT to a file handle that is not opened. If the
DA writes to STDOUT, it only get's error-messages (and it
normaly ignores them). The GEMDOS supports 75 open files, the
default redirect handle is handle 74 ($4A). Chameleon also tests
whether this handle is in use and only redirects the STDOUT
output if not.
Some details:
-------------
'The Chameleon' is TOS indespended, it uses no illegal system-
variables. It hooks into the GEM- and GEMDOS-vector with the
XBRA-ID 'Cham'. The trap handler supports all from 68000 up
to 68030.
If you choose the menu enty, a file selector appears and you
can select an DA. This DA is now loaded and started. In the
vectors, Chameleon protocolls every demand of system resources:
Windows, VDI-workstations, resource files, memory blocks and
also the loding of GDOS-fonts, hiding of the mouse...
With this information 'The Chameleon' can restore the original
state.
If the user want's to unload the DA, all system vectors are
tested, whether they point into one of the memory blocks of
the DA. Chameleon follows XBRA chain.
If the DA hooked into the system, Chameleon can't remove it.
You get an alert with a warning. If the DA uses the XBRA
convention to hook into the traps, 'The Chameleon' can unhook
it from the vectors.
If a GEMINI-message arrives with the string '$KILL', the DA is
un