PC Plus HelpDesk - issue 247
|This month, Paul Grosse gives you more insight into
some of the topics dealt with in HelpDesk
From the pages of HelpDesk, we look at:
- Galleries in web browsers;
- Standard exposures;
- GIMP my pics;
- Custom key sequences in the GIMP;
- Density ranges;
- Internationalisation (i18n) and Localisation
- Stop the screensaver; and,
- Processor demand.
Galleries in web browsers
Programs such as Microsoft FrontPage will do a lot of
work for you if you want to produce web pages quickly and
it can be quite helpful if you are in a hurry and you are
not that bothered how your code looks and how it renders
on various web browsers.
|On the right is a web page that was created
with MS FrontPage (I have substituted the images and
otherwise bowdlerised it so that the identity of the
original pages shall remain hidden). This is how it
renders in IE6 and you can see that it is all right
(except that the HTML code is awful to look at with messy
directories and bits everywhere and, each time you click
on an image, in the thumbnail strip, it produces a
You would expect that it would
render all right in IE after all.
|This is the same page as rendered by
Firefox. If you are wondering what has happened to the
menus on the left and the right, they are still there and
the scroll bar at the bottom should give a clue as to
what has happened to them.
Firefox, it seems, looks at
the list of thumbnail images and notes correctly that
there are no spaces between the tags and therefore they
should not be wrapped at all.
|This is how it is arranged on the page. If
only they made monitors with 4:1 aspect ratios.
|This is how it renders on Konqueror. Whilst
Konqueror might seem to aim at a small market, its KHTML
rendering engine is the one that is used by Mac OS X's
Safari web browser so, if you can get your pages looking
all right on these three, you have a lot of the
Internet's browsers sown up (okay, so there are others
but so far, nobody's sent me a press copy so that I can
You might notice that the thumbnails
are rendered as a table. In the code for this page, there
are spaces within the tags that appear every block of six
thumbnails. It seems that Konqueror sees these, works out
that it ain't going to fit on the page unless it breaks
it up some way and so decides to break it there. Looking
at the code, I would say that that was the intention.
Any way, it is totally unacceptable that this page
renders in three different ways in these browsers. The IE
example is clearly how it intended to look so we have to
get a way of generating that in all three browsers, using
a single version of the page. Also, people with any sense
don't browse with scripts running so it also has to be
able to work without any scripting
|One way of doing this is to use
embedded, floating frames - these are called 'iframes'.
They are like images in that they can be placed anywhere
on a page but they are also effectively a little browser
Like normal frames, you can give them names and
as a result, get other hyperlinks to load new pages into
the iframes, using 'target="whatever"' in the
anchor tags. You will need to have a regular page that
loads the images but also you will need a web page that
contains all of the thumbnail images and one each for the
full-sized images. Whilst this might sound like a lot of
work, you can write a Perl script to do it automatically
Here, we will use two:
- One to hold a strip of images (complete with its
own scroll bar generated by the browser); and,
- One to have the image we want to view.
Note, if you only need to display full-sized images
that are all the same size, you can get away with a
second iframe window that only displays the image - if
you need to display different sized/aspect ratio images
or you need to add more coding (such as links or notes)
you will need to create a web page for each image.
So, first of all, what images and pages do we need and
what is a reasonable way to structure them?
|If we have:
- a subdirectory called 'gallery' (for want of a
better word but it will do for now) that contains
the gallery web page itself (you could have it on
the server root if you wanted as all the other
pages here refer to it and not the directory it
is in, so it is totally mobile);
- within that we have one called 'pics' that
contains all of our full-sized images and two
- one called 'pages' that has the tiny html pages
that we will need to be displayed in the main
window - note that if we are only displaying
images that are all the same size and there is no
need for any links or notes with them, you can
dispense with this one; and,
- one called thumbs.
If you wanted to run multiple galleries, you could
organise it so that you had a pics directory for each and
you could also have a sub-directory with the large
pictures in it instead of pics - this would allow you to
keep the layout simple but this will do for now...
|Here, you can see the directories with their
files in them.
Note that in 'thumbs', there is the
gallery strip page - galstrinp.html - which we will cover
First of all, iframes...
|The coding for an iframe is quite simple
and is largely like the image tag (although you needs a
tag pair for some reason and usually, there is nothing
between the start and end tags). We will organise it
using tables as this is robust in almost every browser.
of all, the page that holds the two iframes has coding
that looks like this ...
<td align="left">Click on an image ...</td>
<td><iframe hspace="0" vspace="10" width="90%" height=100
... which renders like this ...
|Click on an image ...
|and the coding for the other frame looks
<td align="center" valign="top"><iframe align="center"
hspace="0" vspace="10" width="600"
height=450 bgcolor="#ffffff" name="mainpic"
... which renders like this ...
|Note that if you click on the strip
above, the image will change in the iframe just above.
how does it work?
The code for the first frame - the galstrip.html
file - looks like this...
<body leftmargin="0" topmargin="0"><table
<td align="center" valign="middle"><a
<td align="center" valign="middle"><a
It is set out as a table so that it is robust. If you
had pictures which were a mixture of portrait and
landscape, you could use align="center" and
valign="middle" within the <td> tag
to make sure that everything was spaced nicely - use
hspace and vspace to modify this was well if you want to.
You can also (as you are coding this by hand) use the alt
tags so that each image can have a description if you
Note that each thumbnail image is a hyperlink to a
page (or it could be just an image if you wanted) that is
then targetted at the other iframe - the one called
One other thing of note is that the body tag takes
leftmargin="0" and topmargin="0" so
that there is no space at the top or left of the window.
If you left this out, you would get a gap on those sides
and it would mean that the iframe window needed to be
taller than the images. Also, note that the iframe height
for the strips needs to be tall enough to hold the scroll
bar (which is usually around 16 pixels high) so take your
maximum image height (plus twice the vspace value) and
add 16 to it to get the height of your thumbnail image
strip with scroll bar.
|The code for each of the pages that are
called by galstrip.html looks like this...
<body topmargin="0" leftmargin="0"><table
border="0" cellpadding="0" cellspacing="0"
width="100%" height="100%"><tr><td align="center"
...again, note that the image is in a page that has no
top or left margins and also, that there are no spaces
between tags within the body (this can be interpreted
differently between browsers so iron out any potential
for disagreement here).
|So, it is already to
assemble as a page and on the right, this is what it
If you click on the image on the right, the
full-sized version will open up in a new browser window
and you can play around with it.
click on the image on the left, you will open up the
directory in another browser window with the files in it
so that you can have a look.
want to do photography in an objective way, you need to
standardise the way that you do things. One element of
that is to standardise the input part of taking a
photograph. The problems is getting hold of something
that has standard densities.
On the right, you can see a shot of the Kodak
Professional Photoguide (ISBN 0-87985-100-7, first
edition, first 1981 printing). I dare say that there are
others but I have used this one for years (since 1981 in
The idea is that you take your photographs and also,
in the same lighting, a picture of this. Then, you can
modify your processing so that the final prints have
roughly the same densities as the images on the right.
Why would you want to do this? Because, if you were
taking pictures of paintings or something else that had
to be reproduced accurately, you would need to get it
right. So, what do those numbers mean?
On the left is a matt sheet of 18% grey card. This
reflects 18% of the light that falls on it and being matt
(it is a fairly good matt finish as well), it will give
you a good idea of the incident light at that point. If
you aim a light meter at this (from around 6" or
15cm but so that you don't cast a shadow on the card) you
will get the same reading as if you slide the little
white dome over the sensor. So, if you have a light meter
without a white dome, use one of these instead. 18% grey
is also the average colour of your image if it is exposed
On the right, there is a fold-out section with the
primaries and skin tones on it - along with their names
so that you can recognise which is which if they get
separated in the processing - and, a photographic print
of some standard exposures. These have the absorbencies
printed on them and that allows us to work out the values
for correction purposes.
The amount of light absorbed divided by the amount of
light illuminating the area gives us a number which is
analogous to transmission (in spectrophotometry) but if
we take -log10 of that,
we get the absorbency. So, to work out the absorbency
from a photographic perspective, we need to know what
white looks like (I0)
and what our test piece looks like (I). So...
|Absorbency = -log10(
|To work the other way, we can use a calculation that
gives us the proportion of light reflected and then - as
we are working with a system that gives us values between
0 and 255 - we can multiply that by 255 to give us our
If you remember, on the SuperDisc for PC
Plus HelpDesk issue 236, I wrote a calculator that takes
arguments in calculator order (no BODMAS), you can use
that like so (where you replace 'n' with the absorbency
value you want such as 0.7 or whatever)...
calc 10^n a-1 b/a 1-c d*255
...and that will give the proportion of reflected
light (This is not to be confused with reflectivity which
is the power and therefore (I/I0)2
) as the penultimate line and the RGB value as the last
Our absorbency test sheet has the following values;
0.1; 0.4; 0.7; 1.0; 1.3; 1.6; 1.9; and 2.2. For good
measure, I'll throw in the figures for the 18% grey as
This shows a limitation of a 0..255 system
|So, now you know what to aim at with your colour
Just in case you can't find
such a reference, if you click on the image on the right,
it will open up such a reference in a new browser window.
You can either print this out on your own printer or,
you can click on the links in that page to open a JPG or
GIF image of the page that you can then copy to an SD
card and get printed out at a chemist or photography
GIMP my pics
After a long hard holiday of taking photographs, you
will, once you have recovered from the exhausting process
of getting back into the swing of things, like to look at
your digital pictures. However, there are some
limitations to digital images and there are some features
that lead to problems that more conventional cameras tend
not to suffer from to the same degree.
- Digital cameras tend to have a large screen on
the back that allows you to see the image in a
way that is analogous to the view through the
viewfinder of an SLR camera. The main fault with
this is that it is always perfectly aligned with
the scene - if you tilt the camera, the scene
stays aligned. Whilst this is true of both
systems, with a viewfinder, you put your eye up
to the eyepiece and if the view is not straight
with the border of the finder or any structures
within it, you straighten it up. So, the first
thing that needs doing is straightening the
- Next, many people who use digital cameras will
not have used a conventional camera and then
taken their film through the developing process
themselves. So contrast reducing masks (which
would need a higher dynamic range than a normal
digital camera would give in the first place) and
other darkroom tricks are not familiar to them.
In fact, most people who process their own
digital images on their home computer will only
have used gamma correction to lighten or darken
their images. Some of them might have adjusted
the limits as well but that is about it. This is
usually the fault of the image processing
programs that come with digital cameras.
- Lastly, many places you visit
will have traces of human activity that you might
want to remove. Whilst this is best done before
you take the shot (moving chairs or bins or other
things) there are some objects that you cannot
move such as the National Grid's power
transmission cables and pylons.
So, to summarise: we need to straighten the image;
adjust its tone ranges; and then, clone out anything we
don't want. There are other steps but we are not covering
But what program can do this and the many other things
that we need to do? Fortunately, we don't need to spend
hundreds of pounds on any commercial program to get what
we need as there is a very good quality program that is
free. It is called the GIMP and if you can't get a copy
from the PC Plus SuperDisc, you can download it from http://www.gimp.org/.
In addition to running on Windows, it also runs on Mac
OS X, Linux and UNIX and, it uses the same interface in
each of these OS groups so if you learn how to use it on
one, you can use it on the others.
Custom key sequences in the GIMP
The GIMP is quite easy to use - all you do to edit
your image is to right-click on the image you want to
edit and work your way through the menus to get to the
tool you want. In later editions of the GIMP, there is
also the same menu across the top of each image. The
GIMP's menus are laid out logically and like every
program, the more you use it, the easier it is to know
where any particular tool is. However, like every GUI
program, the keyboard is quicker at menus than the mouse
and the GIMP accommodates this very well...
people like to use key sequences to get to the tools they
want quickly, instead of chasing through layers of menus.
The GIMP can be configured quite easily to accept any key
combination to any tool or other menu item. This can help
if you use two image processing programs of which the
GIMP is one. For example, on one system, I use Micrografx
Picture Publisher. To paste the contents of the clipboard
into a new image, you use the combination
[Ctrl][Shift][N]. In the GIMP, I can give this key
combination to the same process so when I want to create
a new image from the contents of the clipboard, all I
need to do is use the same key sequence as I did in
Picture Publisher. Here is how to do that...
On newer versions of the GIMP, you need to turn on
dynamic keyboard shortcuts (this allows you to program
the key combinations - you can use the existing
combinations or those that you have already programmed
whether this is on or not).
To do this, click on the 'File' menu item and select
'Preferences'. Under 'Interface', in the 'Keyboard
Shortcuts' frame, make sure that the 'Use dynamic
keyboard shortcuts' checkbox is checked then click on
'OK'. Now, you can program your own like so...
an example, we will introduce a shortcut key combination
for the 'Levels' dialogue box.
First of all,
right-click on an image (any image will do) and then work
your way through the menus until you get to where you
want - in this case 'Layers'/ 'Colours'/ 'Levels...' and
without clicking on it, make sure that 'Levels...' is
highlighted and then press [Ctrl][Alt][Shift][L] and this
key combination will appear as you can see it in the
Now, whenever you press [Ctrl][Alt][Shift][L] (it
doesn't matter which order you press the modifying keys
[Ctrl] [Alt] or [Shift] as long as you press [L] when you
have the others already pressed), you will get the
'Levels' dialogue box.
These keyboard shortcuts will be saved if you have
that box checked and you can, if you want, reset them to
the original set of shortcuts you had when the GIMP was
In addition, you can program other key combinations
for other features at the same time.
This is the image we are going to use.
As you can see, it could be from somewhere in the
American Mid-West but in reality, it was taken just a few
miles away from a Japanese car factory in the English
It was taken with a digital camera using the TFT
display on the back of the camera which will always give
a correctly aligned image. You can see from the border of
the photograph that the camera wasn't straight when it
|If we look
at the image as we would see it on the computer, we
notice that there is a distinct tilt. This ground is
flood plane and is essentially flat and horizontal so it
is not that, it is the camera.
So,click on the 'Rotate'
tool in the GIMP toolbox and then click on the image
get a grid overlaid on the image
In the middle of it,
there is a little filled grey circle that you can drag
where you like - this is the point around which the image
You can drag the grid and it will rotate around this
However, how do we know how much we need to rotate it?
Normally, when you move a grid like the one in the
screenshot on the right, it will rotate it in that
direction so the image will end up twice as rotated.
double-click on the tool icon in the tool box, you will
get the 'Tool Options' dialogue box like the one on the
Note that you can run the rotate tool in two
- Forwards, which moves the picture as far as you
have specified with the movement of the
superimposed grid; and,
- Backwards, which moves the image back to where
the grid was before you moved it.
So, select backwards and rotate the grid so that the
formerly horizontal lines now run parallel with the
clicked on the image and the grid appeared, the rotate
dialogue box also appeared. This is it on the right.
can see just how small the correction angle is as well -
only 1.56 degrees.
Note that the angle of the grid is the angle relative
to the centre of rotation and relates to where you have
the mouse in relation to that. In other words, if you
can't get the angle quite right - just a bit one way or
the other - then move the mouse further away from the
centre of rotation and you will get a finer resolution on
Once you have got it right, click on the 'Rotate'
this is what you have.
Note that if you don't like the
results, you can press [Ctrl][Z] to undo the edits, one
at a time, and [Ctrl][R] to redo them.
This is a
typical picture where the sky is fairly burnt out and the
fields are too dark.
The main control that most image editors have is
gamma. This allows you to lighten and darken things.
So, let's use gamma to darken the sky so that we can
see the clouds...
is what we get.
The sky looks reasonable but we can see
even less of the field.
So, what happens if we use gamma to lighten the
can't see anything in the sky - so much for taking that
However, not all is lost.
Let's look at the distribution of densities in the
image using the levels tool.
can see that we have a lot of dark and a lot of light
pixels but not a lot in between.
This explains why the
gamma correction didn't work because whilst we were
expanding one part of the density range, we were also
compressing the other.
So, how do we spread the densities into the gap in the
|If we use
the curves tool instead, we have much more control over
where the densities go.
In the diagram on the right,
you can see that the x axis is the input density and that
the y axis is the output density.
Just to make it clearer where things are in your
image, the graph from the levels dialogue box is
superimposed over it. Now, we can fix the image.
When you start off with this tool, the line you can
see has no points on it apart from at the beginning and
at the end and it just travels in a diagonal straight
line. You can grab one of the end points with the mouse
and move it to where you want or, you can click somewhere
on the line - introducing a new point - and drag it where
you would like the line to go. To remove a point, just
drag it out of its range.
Being a smooth curve (look at 'Curve Type' towards the
bottom right), the computer draws a smooth curve between
the points. If you want to make more of a 'corner', you
can just add another point so that the line goes where
you want it. If you want to make the curve finer, you can
click on the 'Free' curve type (the one with the jagged
line) and then, you can make the graph do what you want.
For our image here, the area on the left can be spread
over more of the density range - here, taking up around
three quarters of it and the area on the right can still
occupy the range it did before but in this case, the
brightest density in the original is not as bright as it
could be so that is moved over as well.
Normally with a graph like this, I would flatten the
bit in the middle to prevent solarisation of the
intermediate pixels which can be an unwanted effect here.
is the final result. We can now see the detail in the sky
(remember that we extended the density range up to white
so its contrast is increased) and the detail in the field
(which again has had its density range greatly extended).
The next step is to remove the National Grid and the
way of doing this is to use the clone tool. The clone
tool is like magic paint where your paint is your
When dragged across an image, the clone tool picks up
a piece of the image and translates it through a vector
to where the mouse cursor is. This has the effect of
keeping image detail (such as noise and other textures)
as well as keeping any tones that are their so that if
you are copying something across a density gradient, you
effectively 'draw' with the local colours and textures.
on this tool icon and you will be able to draw over any
area of the image with parts of the image itself.
double click on the tool icon, you will get the Tool
Options dialogue box - the important bits being that:
- you use the image as a source; and,
- that you use the aligned option.
The aligned option means that the vector (x,y offset)
that you chose originally will be used again and again
until you redefine it. If you chose non-aligned, it would
use the original source point each time you started a
'draw' tool, the size and other qualities are taken from
the current brush.
Access this by clicking on the brush
area in the main toolbox.
Note that there is an option to generate your own
brush shape and hardness.
|So, to use
the clone tool once you have configured it the way you
want it (or just used the defaults), this is what you
- hold down [Ctrl] and the mouse will change to a
cross-hairs. Click the mouse where you want your
source image to be taken from initially (or, if
you have non-aligned, each time you use the clone
tool). Release the [Ctrl] key;
- move the mouse to where you want to start drawing
and click there (this will store the vector (x, y
displacement) for the drawing you will be doing);
- move the mouse around just as you would with any
other drawing tool - releasing the mouse when you
If you have selected 'aligned', the next time you
click the mouse to clone, the vector will be the same.
If you have selected 'non-aligned', the next time you
click the mouse to clone, the starting point will be the
same and a new vector will be stored and used.
So, how good is the clone tool?
|This is the
original image with the 440,000 Volt pylon and the odd
car factory chimney.
|If you do an
'edge detect' on it, you can see the detail in the sky.
all, let's try just copying a gradient over the sky that
This is the mask we will use...
|And this is
the end effect. I took the colours (using the dropper
tool) of the sky at the top and bottom of the gradient
and used the gradient fill tool in the above mask. It
does look rather flat and featureless - rather false.
|This is what
it is like with the edge detect used in the same way as
above. You can see that the natural grain/variations in
the sky are taken out, leaving us with a gradient that is
uniform. We need to be able to copy the natural gradient
from the sky itself to make it more convincing.
|This is the
result of using the clone tool. I took a source area that
was close to where the clone tool drew so that the
density was fairly similar. It does look a lot better.
|And this is
the edge effect used in the same way as above. You can
see that the texture of the sky has remained.
|If used carefully, the clone tool can be used to
remove imperfections in images such as skin blemishes on
models' faces, birds in the sky, power lines and so on.
Internationalisation (i18n) and Localisation
Internationalisation and Localisation (or if you are
not a fluent typist; 'i18n' and 'l10n' because there are
18 characters between the 'i' and the 'n' of
'internationalisation' and 10 characters between the 'l'
and the 'n' of 'localisation') are two separate but
Internationalisation ('i18n') takes a program and
separates the words and phrases used in the user
interface, from the programming itself. These can be
stored in an external database and accessed by the
program when it needs to. So, if your program previously
displayed the word 'File' in a menu, it now looks up the
word that it needs to use in that place and displays it
-- thus 'File' appears again.
that might see totally pointless, the process of
Localisation ('l10n') can replace the default database
with one in another language. This makes it comparatively
easy to make a version of a program that works in any
language because you don't need to go through many
thousands of lines of code, looking for bits of text and
then translating them - instead, you just work through a
However, this needs to be done properly and there are
two processes to test. The first is i18n and this can be
tested by using a language to check that everything has
been caught (no menus or dialogue boxes have escaped the
The second is l10n which a local translator can do
once the i18n has been completed.
There are a number of test languages that are used for
i18n and if you look at the language section of Google,
you can see some of them - on the right, you can see the
Google interface in Klingon.
- Bork bork bork! (the Swedish chef from the
- Elmer Fudd (Bugs Bunny);
- Hacker (l33t language);
- Klingon (Star Trek); and,
- Pig(eon) Latin.
Just click on 'Language Tools' from the main search
page to see them and try them out for yourself.
Little is more annoying than something that has just
stopped working for some reason and looks as though the
only way to get rid of it is to have to kill it (with the
exception of having to reinstall Windows). If all else
fails, you will need to kill its window although I would
recommend finding out why it appears to have stopped (it
might be waiting for a resource to become available or in
the middle of a long procedure) and solving that first.
This is, in
effect, a last resort.
There is a little utility called xkill that you can
- locate on the KDE menu;
- put on a panel (once you have located the icon on
the menu, you can drag it to a panel and drop it
on a blank bit of panel real estate and it will
copy itself to there ready for future use); or,
you have a console open, just enter xkill.
When xkill is running, it will display the skull and
crossbones that you can see in the screenshot and the
next thing that you click on will be killed. Note that if
you have a multi-window application open - for example,
the GIMP - then all of that application will be closed
down. If you click on something by accident (such as
KDE), you will need to know how to restart it.
If you are going to put its icon on a panel, then as a
precaution, we would suggest that you don't have an icon
for xkill anywhere you are likely to click on it by
accident. Also, any icon you choose should look
If you do, then make sure that you can start up a
throw-away application (one that can be killed without
any consequences such as a dummy xterm session) to kill
that instead. One solution is to configure the KDE
shortcuts so that the Windows/Tux key will start the KDE
menu from which you can use the arrow keys and enter to
start a program of your choice.
Like all powerful tools, this can be a double edged
sword because you can make mistakes with it so be
Stop the screensaver
screensaver start is particularly annoying if you are in
the middle of doing something and only left the machine
for a few minutes and you know that from that point on,
you will have to use your password to get to your account
However, on KDE (and on Mac OS X, I am told), you can
configure the system so that when the screen trips into
screen saver mode, you have a configurable amount of time
to get to the computer to rescue the situation.
If you right-click on the screen and then select
properties, you get the screen on the right.
settings frame, you can configure the amount of time you
have to get to your machine - here, 20 seconds.
make this time too long though because if you are waiting
for it to become safe to leave, you will have to guess
this last time.
On a personal note, I have been using Windows (which
does not feature this) and KDE (which does) for years and
it is a lot better to know that you have a bit of time to
got back to your machine.
If you want to find out how much processor time and
other resources a program uses - effectively finding the
minimum system resources required to run a program - you
can always use 'top' but if the program you are
interested in uses all of the screen - such as a game
like Tux Racer for instance - you will have to think of
this from another angle.
'top' provides a useful, real-time display of
processes and how much resources they use. However, it
does require a console to work in so if you have a second
machine, use the first method otherwise, you will have to
look at the second way of doing this.
1. One way of hacking this is to use
your slower machine to ssh into the faster one and run
top. This way, you will be able to see how much power is
being used in real time although this needs both machines
in the same place or, you need to borrow someone to play
the game while you watch top on the other machine.
2 a. The other way of doing this is
to use top from the command line in batch mode. With this
method, you can look at other processes that were running
at the same time. Open up a shell and when you are ready
to start Tux Racer, enter...
top -b -d 3.0 -n 30 > tempfile.txt
... then run Tux racer.
switch makes top run in batch mode, the '-d'
switch specifies the duration in seconds between each
sample and the '-n' switch tells it the
number of iterations to make. The '>'
tells the system to direct the output to a file called 'tempfile.txt'
which is in the current directory. I found that with
around 80 processes running, 30 iterations gave a file
size of around 250kB.
Once you have created your file (and finished playing
Tux Racer), you want to see the lines with your process
on it. In batch mode, top outputs information on all of
the processes which is why it is such a large file. The
lines you are interested in will be dispersed amongst
these other lines so, to sift these out, we use grep (get
regular expression) to search through the file and print
out each time tuxracer is found. To do this, enter...
grep tuxracer tempfile.txt
You can do this for any of the processes that were
running at the time.
2 b. However, if you are pushed for
disc space or you are only interested in the one process,
type the following two lines instead...
top -b -d 3.0 -n 30 | grep tuxracer > tempfile.txt
This pipes the output of top, through grep which
filters it and then that output is redirected to the
file. This makes the file much smaller as we are only
interested in looking at one process this time. Being a
file that has already been filtered by grep, you then
look at using 'less' once top has finished. This way of
doing it generates a file of only around 2kB for the same
So, you know the processor speed (in
this case 1.8GHz) and you know what proportion of the
processor time is needed during normal playing (around 60
per cent) so you can work out roughly what speed
processor is needed (in this case, around 1GHz plus a bit
for other things going on that are needed).
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