DPSwitch - You may never need your "System" button anymore!
===========================================================

What is it?
-----------
DPSwitch is a task switcher for the Psion Series 3a.  It cannot launch
tasks, it only switches between opened tasks.  If you need a complete
task switcher + launcher, I suggest you take a look at "Finder" from
Tom Dolbilin or "Taskman" from Mark Esposito.

Why another task switcher?
--------------------------
DPSwitch was originally writen for my own specific needs:
-fast task switch hot key (control-a)
-doesn't use much memory (10k only)

The other two task switchers I mentioned were simply too big and
memory hungry for my little use...  so DPSwitch was born.

I thought the program might be useful to other people so I release it
here as FREEware.  If you like it, I would appreciate a little EMail.
If it really makes your life much easier or saved your Psion with a
broken "System" button, small tokens of appreciation are always
welcome ;-) Send them to me at:

    Daniel Pfund
  19, ch. Tirelonge
    CH-1213 Onex
    Switzerland


EMail: Pfund3@uni2a.unige.ch (until 11Oct96) or 
Pfund@mail.dotcom.fr afterwards.

You will always find the latest versions of all my programs on my
homepage at:

 http://www.geocities.com/SiliconValley/8130/


Installation
------------
Installing is very easy:

-if you have a Series 3a:  just copy the opa file (DPSwitch.opa) to any
 \APP directory on one of your disks (M A or B).  To install, press
 Psion-i from the System screen and select DPSwitch.  You'll see the
 icon appear on your System screen.

-if you have a Series 3:  copy the opo file (DPSwitch.opo) to your \OPO
 directory.  You must use RunOPL in order to run it (sorry, there is no
 icon on the Series 3 version).

If you want, you can also rename the Series 3a file to DPSwitch.opo and
put it into your \OPO directory and launch it from the RunOPL icon.
This avoids clogging up your System Screen and also saves you an icon
(for the 50 icon limit of the Psion).

Usage
-----
Leave the program open all the time for maximum efficiency.  The hot
key is shift-escape.  Apart from that, I believe it is really easy to
understand what the program does...

Just one limit though (that I haven't reached on my 512k Psion):  it
will only list the first 9 active tasks.  This is a Psion limitation
as OPL strings are only allowed 255 characters max.  I know a way
around this (see the file Longlist.zip at the Imperial College
archive) but I don't want to implement such a memory hungry method for
such a small problem!

Advice to programmers
---------------------
DPSwitch reads the process names and files used by each running app
every time it is activated.

If you run a lot of 3rd party software written in OPL, you'll see that
most of them appear under "SYS$OPO.$xx".  This is the default name
from the RunOPL interpreter.  I strongly suggest to OPL programmers to
rename their process to their program's name with the following code
example:

name$="Filename"+CHR$(0)
REM name$ must be defined with correct size! (9 max)
CALL( $0C88,CALL($88),0,0,0,UADD(ADDR(name$),1) )

The CALL($88) gets the current process' Id and the CALL($0C88...)
renames the process with the selected Id to the name name$.  Be
careful to enter the addresses correctly!

Legal section
-------------
DPSwitch is provided "as is" and I cannot be held responsible if it
crashes your Psion or of any other misbehavings it may occasion.  I
have tested the program myself and I use every day, so I would say
that such a case would be highly unlikely...  But you never know, if
you have encoutered a problem, please report it immediately to me so I
can take correct action against it in future versions.

I hope you'll like the program.  Mail me any comments you may have.

History
-------

ver Date    Comments
--------------------
1.0 13Mar96 First public release
1.1 14May96 Added System Modal call + Series 3 "Classic" version
1.2 29May96 Removed System Modal ;-) + changed hotkey to Shift-Esc