Patch to fix Serial Link power monitor problem.

I'm sorry to report that the current patch to fix the problem with 
the Serial Link recording a high current useage after the link has 
been closed has shown up an (otherwise harmless) bug in the built in
serial driver.

The effect of the bug is for an open such as IoOpen("TTY:A") to hang 
if no device is present. If the hanging program is then terminated 
with spy or Psion+Shift+K from the shell then subsequent call to open
would forever return "Device in use error".

The problem shows up when there are two PDDs for the Serial driver
with the same name. The fix is simply to change the name of the PDD 
installed by the patch program. This we have done.

This is the reason for some of the problems reported just recently on 
Cix and Compuserve.  Thanks to all reports, especially to ANDYSC @
CIX for a precise description of circumstances when things went wrong.

As the patch is a permanent patch it will be necessary to soft-reset 
the S3a before applying the updated patch. The dates on the updated 
patch are both 15th November 1993. The patch program itself claims to 
be V1.01F.

As a matter of interest the patch program will not apply the patch to 
a version of the OS that does'nt need it. In EPOC terms this is any 
version greater than V318F. In terms of the ROM version number this 
is any version greater than V320F.
--------------------------------
Instructions from patch 1


Files in this zip
-----------------
    s3apat1.txt         This documentation
    s3apat1.img         The patch program
    s3auar1.pdd         Used by the patch program

Description of problem
----------------------
In some circumstances, the S3a "Usage monitor" dialog can
over-estimate, by up to a factor of two, the amount of current being
used by the S3a.  Eg an average current of around 60mA can be shown,
whereas the actual figure should be around 30mA.

These circumstances are when Remote Link has been turned on, and then
turned off again BEFORE the 3-link cable has been removed from the
expansion port.  (Or if you make any other use of the serial port,
such as the Comms program, and close down that program before pulling
out the cable.)

Note that the ACTUAL current used in this case is correct, ie the
same as before turning Remote Link on.  It is only the ESTIMATE of
the current consumption that is incorrect.

Note also that, as it happens, this over-estimate does not occur if
users pull out the 3-link cable before turning Remote Link off (nor
does it happen if they leave Remote Link on all the time, regardless
of whether the cable is plugged in).

The patch
---------
A simple patch is available, with the effect that the current used is
correctly estimated in all cases.  Anyone who wishes to have a more
accurate value displayed in the "Usage monitor" dialog should apply
the patch as follows:
    1. Copy both the files S3aPAT1.IMG and S3aUAR1.PDD onto the \IMG
       directory of an SSD (or on internal memory)
    2. Select the entry S3aPAT1 under the RunImg icon in the System
       screen, and press ENTER.  (The program S3aPAT1.IMG exits
       almost at once.)
    3. That's all!

Once the patch is applied, there is no need to keep these two files
in place.  However, the patch will need to be reapplied if the S3a
is ever reset.

Trying to apply the patch twice is harmless.  So is trying to apply
the patch to an S3a with an operating system that doesn't need the
patch.

Note again that the patch has no other effect on the operation of the
S3a, and that there is no need to apply it, other than for more
accurate information purposes.