re: JFW 9 Beta Memory Issues
- From: Joseph Lee <joseph.lee22590@xxxxxxxxx>
- To: jfw@xxxxxxxxxxxxx
- Date: Sat, 06 Oct 2007 16:05:15 +1200
Hi Brian,
This kind of thing is called memory leak--a
condition where the application executable
fails to release memory that it no longer
needs. From my testing, it seems that it
does not occur to me. The process of
obtaining and releasing memory is normal
behavior for applications. This is because
of the following two reasons:
a. If an application is composed of
threads--a small application code--of
execution (known simply as thread), then it
is natural for the process to use more memory
than expected. More threads within the
executable translates to more memory usage.
Contrary to people's belief, JAWS is composed
not only of just one thread, but multiple
threads as well. The jfw executable consists
of JAWS tracking engine which gathers
information on the screen, synthesizer
controller that relays information gathered
from tracking engine and sends it to speech
synthesizer such as Eloquence, and braille
display unit which relays information on the
screen and translates to braille characters
(this works properly when a braille display
such as PAC Mate Portable is attached). JAWS
also includes Virtual Buffer which is
activated when applications that require
virtual cursor is running, such as Internet
Explorer and Anobe Reader. The application
you run, the more tracking routine is needed,
consequently leading to more memory usage.
And once the thread is no longer needed, jfw
releases memory associated with the thread.
b. If an application needs to access cevices
and software modules such as USB devices and
drivers, it needs more memory to load device
drivers and/or software modules. In order
for JAWS to run properly, it requires Mirror
Display Driver. The initial memory usage of
jfw, coupled with device driver for Mirror
driver results in more memory usage than
expected.
Hope it was not that "too techie" for you.
If you want simpler explanations, let me
know.
Cheers,
Joseph P.S.Tested using Windows Vista and
JAWS 9.0.353.
----- Original Message -----
From: "Brian Hansen" <bc.hansen23@xxxxxxxxx
To: <jfw@xxxxxxxxxxxxx
Date sent: Sat, 6 Oct 2007 16:20:06 -0500
Subject: JFW 9 Beta Memory Issues
Please forgive me if this has been recently
discussed, but I just now got back on the
list.
Have any of you noticed that even when the
screen isn't changing, JFW 9 Beta is
continuing to grow in memory? If you go into
the "Task Manager" using CTRL-ALT-DEL, and go
to the "Services" tab, hit the letter "j"
until you get to JFW, you'll get the amount
of memory JFW is currently using. Now if you
hit F5 to refresh your screen you'll find
that the amount of memory is continuing to
grow. The amount that it increases seems to
be relevant to the amount of time you let
pass before hitting the Refresh command. If
nothing but the memory usage is changing on
the screen, why is it growing in such chunks,
and why is the amount of time one waits
effecting the size of the memory growth?
Blessings,
Brian
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