If the software was installed as an ubuntu (deb) package the system
knows the location of every file as well as the correct size, mode, and
md5sum of each file. You can list those file locations with the command
"dpkg -L <package name>"

If it was not a proper linux package, then you'll need to consult the
vendor documentation or ask the vendor directly, where they put the files.

BTW "locate" does not perform an exhaustive system search. You might use
the find command, but keep in mind that if you search for "comsol" that
does not match "Comsol" unless you invoke the case insensitivity option.
(find / -iname comsol)

No it is not from the deb package.
I know where the software is installed. Its in /usr/local/comsol40a. The vendor
documentation says that after installing the software, comsol command should
appear in terminal. So, in terminal I typed "com" and pressed "tab", but nothing
appeared. I tried with capital C as well, but no luck.
Is there any way to check whether comsol is really installed or not?

Check /usr/local/comsol40a - if the files are there, they have installed it.

However, that is not in the path, so the comsol installer would have to
take some further steps in order for you to find the executable in your
path.

Typically, vendors who install to non-standard locations have to fix it
up in one of two ways:

1. Edit either your personal profile or the system profile and add the
folders to the path.

2. Make a symbolic link from their binary in /usr/local/bin or other dir
in the path.

All you need to do is find the binary under /usr/local/comsol40a, and
either add to the path the directory it is in, or make a symlink to it
in /usr/local/bin, or make a script call "comsol" to place in
/usr/local/bin which does something like this:

----------------
#!/bin/bash

cd /usr/local/comsol40a/bin

./comsol
-----------------

or similar, to get it to work.

Comsol binary file is in "/usr/local/comsol40a/bin/comsol".
I can not locate path variable in my system. I went to /etc/profile. But, there
is no information about path? Can you give a bit more detail about where to find
path.

To see the path on your system, type:

echo $PATH

The path can be set in any of several places, and on my system it's:

/etc/profile
/etc/profile.d/*
/etc/bashrc
/home/jjs/.profile
/home/jjs/.bashrc

To edit your own path, edit your .bashc file and add this line to the end:

export PATH=$PATH:/usr/local/comsol40a/bin/comsol

Then log out and log in again, or simply type ". .bashrc" which will
have the same effect in that current shell session, as it will add the
location of the comsol binary to your path.

I have assumed that by ".bashc", you meant .bashrc in my home folder.
At the end of ".bashrc", I added the path line you told me. After logging out
and logging in, I typed ..bashrc in terminal. But, I am getting "..bashrc:
command not found".

Note the space between "." and ".bashrc"

Ubuntu is not listed as one of the distros that it supports. Just Debian,
Red Hat, Fedora and openSuSE. Each distribution is a bit different about
where they place some dependencies so there is no guarantee that what will
work with one will work with another. Some things are standard, but there
are enough exceptions that he may have to make some symlinks to make it
work. He should go to their website and look at their support forums. He is
more likely to find an Ubuntu user who has done this there than he is to
find anyone who has used this application on a generic Ubuntu forum. It is
fairly specialised; I had to look it up to find out what it was.

Yeah you are right. Its not directly supported. But, when I searched on google,
it seemed to me that quite a number of people are using this on ubuntu. I guess
I have to contact the tech support.
What I find strange that ubuntu can not locate anything with comsol. I would
have happily accepted if after running "comsol" command, I had received an
error.

I am finding more often the need for a re-boot
after installing a fresh app/program.
(or logout/login)

I recently installed amarok,
and had to re-boot to see my new app
in the GUI. (gnome)

I've never had to reboot in order to run a new app on linux. If I ever
did, I'd be horrified that linux was turning into microsoft windows. In
the case you mentioned, installing amarok, which is a kde app and you
were looking for it to be in the gnome menu, who knows?

But, I'll bet dollars to doughnuts that if you'd simply logged out and
logged in again, you'd have seen the app in the menu.

Finally the path variable worked. I am at least able to see comsol binary file
in the terminal. But, when I run it, it gives me xorg error.
"The program 'SWT' received an X Window System error. This probably reflects a
bug in the program. The error was 'BadDrawable (invalid Pixmap or Window
parameter)'. (Details: serial 1235 error_code 9 request_code 136 minor_code 3)
(Note to programmers: normally, X errors are reported asynchronously; that is,
you will receive the error a while after causing it. To debug your program, run
it with the --sync command line option to change this behavior. You can then get
a meaningful backtrace from your debugger if you break on the gdk_x_error()
function.)"
I searched on internet forums and the most popular (but not recommended)
solution was to downgrade xorg version. I was wondering that do you know how can
I do downgrade xorg version?

Downgrading an X server is not trivial to do - This comsol is obviously
older software, or at least it's built against older X libraries. If
you're running the latest and greatest ubuntu and like it, then you
might want to try running an older ubuntu, or debian, in virtualbox. If
you've no great investment in this system yet, then you might just
downgrade to ubuntu 8.04 or whatever version it needs to be for that
software to work

I was wondering that have you got any link through which I can have a go at
downgrading xserver?
Virtual box apparently kills my pc, as it is not that high specs. And, if
possible, I do not really want to downgrade my system.

Oh, I thought you were running ubuntu on the bare metal - but actually
you're running a pc OS? Are you ubuntu in vmware inside microsoft
windows? That would explain a lot of the performance problems.

Or, if you're using "pc" in the sense of "pc-class hardware", I think I
remember your machine is low spec. I don't know of anyone else
downgrading X on ubuntu 10.04, especially since the version is not at
all the newest, but a rather conservative, older version.

Back in the days of ubuntu 9.04. which performed disastrously with intel
graphics and killed netbook performance, there were repositories set up
to downgrade to the older version of the intel X driver, which was much
better performance wise. Later, there were repositories available frm
which to upgrade to the newer version of the intel drivers, which was
even better.

But there have really been no such problems with the 10.04 X drivers, so
there has been no system set up to fix any such problems.

There may be some info on that, but I'd have to google for it. Chances
are it would be more trouble than doing a clean install of 8.04

I am running ubuntu as a single os (i think that's what you mean by bare metal).
No microsoft at all.

Thank you so much for your help and replies.
I tested that software on Ubuntu 9.04. And it worked!!! Its just xorg problem
with 10.04. Do you know what is so different in 10.04 and 9.04 xorg (just out of
curiosity)?

xorg in 10.04 is a newer version than 9.04 - that's it. I cringe to hear
that you had to go to 9.04 to get it to run. I hope you have an nvidia
card. Intel or ATI graphics performance on 9.04 was disastrous.

Yeah, my experience with 9.04 was horrendous. I was starting to doubt my pc
specs (this is not to say my laptop specs are high). I dont think I have nvidia
card. But, now I am burning ubuntu 8.04 image, because performance is really bad
in 9.04.
Hope the software works in 8.04.

There is actually a fix for the intel drivers in 9.04 - when i was
running 9.04, it was unusable, but I found the fix in the ubuntu forums,
and upgraded the intel drivers. The difference was like night and day.

If you haven't deleted 9.04 yet, I'll look for those 9.04 repositories
for the video performance fix.

But, I mainly use 10.04 and I absolutely love it. 9.04 is on my external hard
drive and it comes handy only if something might go wrong to my current
installation. It came handy yesterday because I tried to downgrade xorg and I
was not able to reboot my system again...

I have been following this thread a little, and I too have some problem with
Xorg setup.
I remember someone telling my that on 9.10 and 10.04 Xorg has been replaced
by
something else, but I can't remember what that was now. I do know that I
can't
configure my touch pad to not be on, so I have to tie my thumbs from the
ceiling to
keep from moving the cursor all over the document while typing. I would like
to find
out what replaced it.

Have you check Comsol forums?
www.comsol.dk/community/forums/general/thread/467/