PC Plus HelpDesk - issue 263
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This month, Paul Grosse gives you more
insight into some of the topics dealt with in HelpDesk.
From the pages of HelpDesk, I look at:
- Beryl on Windows?
- Vista - How much RAM?
- Load files from anywhere;
- MAC addresses;
- Converting PDF to ASCII;
- WEP Keys; and,
- Memorable Hex Keys.
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HelpDesk
Beryl on Windows?
Occasionally, you see on YouTube, the comments from
people who have just seen Beryl for the first time and
they think that it is a Windows plug-in that runs on XP.
However, the bad news for Windows users is that it is
not - it is a windows manager that runs over X-Windows on
UNIX systems such as Solaris, BSD, Linux and so on.
On a UNIX-like system, you have the OS, then the next
layer above has the graphics server (X-Windows in this
case) and then you have the window manager (the bits that
go around the edges of windows such as the title bars and
the edges) and the contents of the windows. On MS
Windows, the distinction between them is not so obvious.
If you lose any part of the GUI, you usually lose the OS
as well. On a UNIX-like system, you just restart the
windows manager or X Windows.
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However, it is not all bad news for Windows
users. There are some 3D cube-style plug-ins for
Windows (these are plug-ins) and the one featured in the
screenshot is "Yod'm 3D". It works similarly to
Beryl - you can configure the shortcut keys in a similar
way - but because it runs as a different layer to the
Aero interface, as opposed to instead of it, it is rather
sluggish in some instances (this is on the same machine
that runs Beryl smoothly).
However, if multiple desktop organisation on Windows
is your aim, this is just what you need. At the moment,
it is free (there are plenty of mirrors listed on Google)
but OTAKU software has taken it over and the new version,
called 'DeskSpace', will lighten your wallet.
One advantage of this program is that it is a
stand-alone that does not need to be installed - you just
run it from the directory you expanded the .ZIP file
into.
There are others - 'cube desktop' (http://www.cubedesktop.com/)
for example - use the one you feel happiest with.
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Vista - How much RAM?
People were shocked when they found out just how much
RAM was recommended to run Vista (as opposed to XP) but
just how much RAM does Vista need in order just to run
itself?
Reports do vary somewhat. Taking a basic installation
of a 64-bit copy of Vista, I booted it up on a machine
with 2GB of RAM and ran Task Manager ([Ctrl][Alt][Del]
and select Task Manager from the list) to see what it
did.
With an uptime of around 2 minutes - just long enough
to boot up and log on - it had consumed just over 700MB
of RAM.
After a further ten minutes or so, it had fallen to
600MB (remember that it uses a page file to dump parts of
memory that haven't been used for a while). However,
opening up a few programs soon pushed it above the 700MB
mark again.
Just how much memory you need depends upon the
programs you run and even different programs that do the
same job can take up different amounts of RAM according
to how they are written.
Image editors are one example of programs that can
take up a lot of memory but how much?
- Photoshop CS3 Extended - 161MB
- Paintshop Pro XI - 71MB
- The Gimp 2.2 - 28MB
Each editor then had the same image - a jpeg image
from a 4M pixel camera - loaded by dragging and dropping
it onto the editor. In Paintshop Pro, it averaged around
27MB but in The GIMP and Photoshop, it was around 34MB.
Editing adds to these figures but the extent to which
this occurs depends upon the options you have chosen for
backtracking your errors with any particular package.
So, with Vista, you can just about get away with 1GB
but you would be advised to have 2GB.
If you do decide to increase the amount of RAM, one
problem you might encounter is that many manufacturers
will fill all of the slots on your mother board with
cheaper RAM so if you have 1GB and two slots, you will
probably find two, half GB sticks. If you want to have
2GB in total, you will end up buying two, one GB sticks.
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Load files from anywhere
If you
want to load a flat text file such as plain text, HTML,
XML, SGML and so on, from a server, you can do it
directly into the text editor itself.
The screenshot shows Notepad running on Windows Vista
but the same applies with text editors running under
various flavours of UNIX as well.
If you are running the KDE window manager, you have
the luxury of many different kioslaves to do the work as
well.
All you need to do is click on 'File', 'Open' and then
type in the protocol ('http://', 'ftp://', 'smb://')
along with the rest of the URI, exactly the same as you
would in a browser address bar.
In the screenshot, you can see the BBC's site's
robots.txt file - this tells spiders where not to look.
The only difference you might find between doing this
on Windows and UNIX is that often, web files are stored
in UNIX format which NotePad does not understand - you
end up with a single line of text instead of separate
lines.
Remember though that one thing you cannot do - unless
you have the appropriate rights - is save the files back
to the server that supplied the file.
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MAC addresses
If you have
a half-decent firewall, you will get emails telling you
about IP-Spoof attacks from certain MAC addresses (such
as the one on the right). The MAC address (six
hexadecimal pairs identifying the Network Interface Card
or 'NIC') is only really of any importance if you have
access to the same physical subnet as that interface
(which is why it is important with IP spoofing).
Network communications rely upon MAC addresses being
unique and they appear to be random. However, that is not
the case at all.
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The first six nybbles (a nybble is: 4 bits;
half a byte; or, a hex digit. Also note that 'nybble' can
also be spelled 'nibble') of the MAC address (the
'Organizationally Unique Identifier' or 'OUI') identifies
the organisation that produced the NIC. These are large
organisations that produce thousands such as Xerox and
Cisco ('00-03-FD-' amongst others). However, not every
producer needs such a large address block.The smaller
companies have a special block called an 'Individual
Address Block' or 'IAB' which allows up to 4096 devices.
These start off with six nybbles ('00-50-C2-') and then
the assigned range, for example, Microsoft's IAB range is
'00-50-C2-00-30-00' to '00-50-C2-00-3F-FF'.
You can use a MAC address to identify the manufacturer
by typing it into http://standards.ieee.org/regauth/oui/index.shtml
. Remember that if it starts off with '00-50-C2-', it is
an IAB.
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On Windows, you can find your own MAC
addresses by opening a console and typing 'ipconfig
/all'. On UNIX, you have to log on as (or su to) root,
then type 'ifconfig -a' -this is because ifconfig
requires privileges as it is a powerful command that can
affect other system users.
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Converting PDF to ASCII
We all know that you can create PDF documents directly
from all of the best word processors but this seems to be
a bit of a one-way journey. Suppose you have exported
your file to PDF and then your machine has crashed or
there is some other reason why you only have a PDF
version and no version that your word processor can
import.
This task
isn't as difficult as you might expect it to be.
On Linux, there is a utility called 'ps2ascii' that
uses the Ghostscript (PostScript and PDF language
interpreter and previewer) engine.
It will convert PostScript ('.PS') or Portable
Document Format ('.PDF') files into ASCII.
It ignores formatting so, as you can see in the
screenshot, the tiny text - 'This is small text...' - is
converted just the same as the larger text.
All you need to do is pass the name of the PDF file to
the program and it will output the text as ASCII to
STDOUT - usually the console. If you specify the name of
a text file, it will save it as that.
With a lot of PDF files, you could easily write a
shell or Perl script that globs the relevant file names
and then saves each file's ASCII content as a separate
file with the same name but with the '.TXT' extension,
ready to parse and catalogue.
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WEP Keys
You might find that that wireless router you've just
bought only uses a 26-hex character code for encryption.
Whilst you can type in a hex number for it, it is not
always that obvious how you should do it on the computer.
The 26 hex-character code is for WEP - you should use
something stronger if you can get it but there are still
many routers around that only have WEP which is better
than nothing.
In your system tray, you should see the wireless
connections icon. Click on that and the Wireless Network
Connection dialogue box opens. Click on the 'Change
advanced settings' link in the 'Related Tasks' box and
the 'Wireless Network Connections Properties' dialogue
box opens. Click on the 'Wireless Networks' tab. Make
sure that the 'Use Windows to configure ... settings' box
is checked and click on your router's network name.
In the properties dialogue that appears, choose 'Open'
or 'Shared' for network authentication and 'WEP' for data
encryption. Enter the 'Network key' and confirm it. The
key index should be set to the same as the one on your
router when you entered the key there. Click on 'OK' and
you should be able to join your network now.
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Memorable Hex Keys
If you have a number of computers to input WEP keys
for, don't want to do anything other than type them in
manually (most secure) but don't want to write them down
(even more secure) there are ways of producing keys that
you can remember. However, you must also remember that by
doing so, you can make them a little less secure because
they become vulnerable to a modified dictionary attack.
Still, here is how to do it if you are interested in
trying it out, or are morbidly curious.
Hex digits represent nybbles so, for a 104-bit WEP
key, we need 26 values between '0' and 'F'. Choosing
randomly produces fairly secure keys but you need to
write them down if typing them in manually - pieces of
paper get lost or copied.
So, how can we make 26 nibbles more memorable? One
solution uses words from existing letters and
substitutions - look at the Perl program by clicking here (both a
UNIX version and a Windows (.PL) version, together with a
dictionary from words consisting of the letters
'oizwhysglpabcdef' that you can play around with. All
good operating systems come with Perl by default. For the
rest, you can get it from 'ActiveState').
Hex uses the letters 'a' to 'f' which is rather
limiting - 77 words including some dodgy ones. If we
substitute numbers with letters, we can go further.
Using a '1' as an 'i' and a '0' as an 'o' gives 264
words and, adding a '2' and a '5' as a 'z' and an 's'
gives us 871 words.
A '6' looks a little like a 'G' giving 1,185 words but
there are still gaps.
If you
type '71077345' into a calculator and invert it (when I
did my A-Levels we were about the first year that were
allowed to use calculators - no memory or even a per cent
button), you get 'SHELLOIL' so we'll use a '7' and a '4'
as an 'L' and a 'h' (optionally a 'y'), giving us 3,757
words from which we can make sentences such as; 'diseased
dodo seizes cafe food' which translates to
'd15ea5edd0d05e12e5cafef00d'.
Rotating '3' gives a 'w' (we already have an 'E' so
making that from a '3' is redundant) and mirroring '9'
produces a 'P' giving 6,188 words, leaving just '8'
unused - make up your own.
Also included below are possible calculator words...
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| Characters used |
Words |
0123456789ABCDEF
abcdef
|
77 |
0123456789ABCDEF
OI abcdef
|
264 |
0123456789ABCDEF
OIZ S abcdef
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871 |
0123456789ABCDEF
OIZ Sg abcdef
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1,185 |
0123456789ABCDEF
OIZ hSgL abcdef
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3,757 |
0123456789ABCDEF
OIZ ySgL abcdef
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3,597 |
0123456789ABCDEF
OIZwhSgL Pabcdef
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6,188 |
0123456789ABCDEF
OIZwySgL Pabcdef
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5,829 |
0123456789
OIZEhS LBg
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525 |
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There are no fixed substitution rules.
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deadly spiced wasps age slowly
deadLySPIcedwaSPSageSLOwLy
dead74591ced3a595a6e570374
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diseased dodo seizes cafe food
diSeaSeddOdOSeIZeScafefOOd
d15ea5edd0d05e12e5cafef00d
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However, remember your security and the
simple rule 'big polysyllables disallowed' or
'b1690745477ab7e5d15a77o3ed' because it makes it too easy
to crack. Using words that are too long allows for
dictionary attacks on your keys (instead of gazillions of
unrelated hex character combinations to choose from
(taking many times the life of the Universe to break),
they have a relatively extremely limited selection of
words to choose from).
| If you chose
six words from a list of 6,188, you would have |
6,1886 |
combinations |
(56,143,803,408,867,444,035,584) |
| instead of |
1626 |
|
(20,282,409,603,651,670,423,947,251,286,016) |
| which,
as you can see, is |
1/361,258,204th
of the strength. |
Have fun.
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