Today I came across this useful trick, which allows me to have lot of space on my screen, even though my screen supports only very low resolution.

First, lets see how to get to know the list of displays attached to Ubuntu

~$ xrandr
Screen 0: minimum 8 x 8, current 2881 x 1280, maximum 16384 x 16384
VGA-0 connected 1600x1280+1281+0 (normal left inverted right x axis y axis) 376mm x 301mm
   1280x1024      60.0*+   75.0  
   1152x864       75.0  
   1024x768       75.0     60.0  
   800x600        75.0     60.3  
   640x480        75.0     59.9  
LVDS-0 connected (normal left inverted right x axis y axis)
   1600x900       60.0 +   40.0  
DP-0 connected 1280x1024+0+0 (normal left inverted right x axis y axis) 376mm x 301mm
   1280x1024      60.0*+   75.0  
   1152x864       75.0  
   1024x768       75.0     60.0  
   800x600        75.0     60.3  
   640x480        75.0     59.9  
DP-1 disconnected (normal left inverted right x axis y axis)
HDMI-0 disconnected (normal left inverted right x axis y axis)
DP-2 disconnected (normal left inverted right x axis y axis)
DP-3 disconnected (normal left inverted right x axis y axis)
~$ 

This is what I got on my machine. And following are the display names as per Ubuntu.

VGA-0 
LVDS-0
DP-0 

This command has listed out other useful information as well. I could only understand the resolutions supported. Following are the resolutions supported by VGA-0 and DP-0.

1280x1024
1152x864
1024x768
 800x600
 640x480

So the maximum resolution allowed is 1280x1024. But that doesnot allow me to have more space on screen. After long searching, I got this.

xrandr --output VGA-0 --mode 1280x1024 --scale 1.25x1.25

This command sets the resolution of VGA-0, to 1280x1024 but it scales it by the factor of 1.25x1.25. Voila :) Now I have much bigger screen.