linux and windows tips, mathematics, and some recipes

Monday, July 24, 2006

How to log in to your Motorola WR850G wireless router


Dear Sir/Madam,

I can't access the control panel on my WR850G. I bought the unit in March and managed to set it up just fine. I enabled WPA-PSK and MAC-based authentication and disabled DHCP (as I was using another device as a router). I've had no problems with it since then, until just now when I bought a new laptop.

Naturally, I needed to access the control panel in order to enter the MAC address of my new wireless adapter. Unfortuately, nothing happens when I try accessing on my web browser (even using the machine which can get a wireless service from the router). I get a ping response from if I change my IP address to

I've tried resetting the router (by holding the reset button for 30 seconds while the power is on). This seems to have no effect and the router continues to transmit the old SSID.

I've also tried running the installation utility which came with the router. This works OK until it gets to the "detecting router" stage, and then stops.

Basically, I can use the router fine as a wired switch, and I can use it as a wireless access point with exactly one wireless adapter (the one whose MAC address I'd entered into the router using the control panel). I cannot access the control panel, hence cannot add the MAC address of my new laptop.

I would very much appreciate any help you can provide me with in solving this problem.


Hello Gihan
try this hook the router to the xp computer remove the modem from the router so just 1 eithernet cable going from one of the 4 lan ports on the back of the router and the other end to the back of the pc now go to start , then click on control panell
now click on internet and network connection then click on net work connection
or you may just see network connection now right click the local area connection and go and left click properties
now high light internet protocal tcp/ip and then click on properties
now put the dot in use the following ip address Then type each of the next but subnet mask should auto populate
subnet mask
default gateway=
Then click on ok then close
now open up internet exploror or mozilla and in the address bar type and see if you can get to the log in screen if you cant you will need to call the # below and talk to our tech support team there incase the router is faulty
let them know what we already did so they dont have to redo what weve already done
Thank you for chooseing motorola
If you need further assitant please respond to this email or contact us by 1877 466 8646
Thank you for choseing motorola you have a great day

Sunday, July 23, 2006

Using Xfig with LaTeX

Xfig is a program used to create drawings with lines, arcs, and splines. LaTeX is a document preparation tool. How do you use them together? I'll discuss a technique which allows you to use LaTeX strings within your figures (for mathematics, Greek text, etc). The first thing you'll need is the following entries in your LaTeX preamble:
The first package is essential for working with graphics in LaTeX, the second is needed because Xfig enters colouring commands into its LaTeX output (even if all the output is black). Fire up Xfig with the following options:
xfig -specialtext -latexfonts -startlatexFont default
If you don't want to do this every time, just add the following entries to your .Xresources file:
Fig.latexfonts: true
Fig.specialtext: true
Go ahead and make your figure. You can enter LaTeX strings as text, these will later be converted by LaTeX into beautiful mathematics.

When you're done with the figure, save it in the same directory as your LaTeX file, let's suppose you name the figure myfig.fig. Export the file as "Combined PS/LaTeX (both parts)". This will make two new files, myfig.pstex and myfig.pstex_t. When you need to use the file in your LaTeX document, enter something like:
\begin{figure} [ht]
\caption{My figure}
You might not be able to see the effects in the dvi file, but you should be able to see your figure if you run dvips mytexfile.dvi to create a PostScript file.

Working with PDFLaTeX

Similar principles apply if you want to end up with a pdf. Of course one simple solution is to run ps2pdf on your ps file from the previous section, but you may end up losing some pdf-specific features, such as hyperlinks. The recommended alternative is to run pdflatex instead of LaTeX. You'll need some changes to the preamble:
You use Xfig much as before, but this time you export the figure to "Combined PDF/LaTeX". This will produce files myfig.pdftex and myfig.pdftex_t. The latter file replaces myfile.pstex_t in the body of your LaTeX document. When using pdflatex, make sure that your Xfig is in the correct orientation (usually portrait).

Most of the information is this post was gleaned from the Xfig website, which contains much more information on using LaTeX with Xfig.

Saturday, July 15, 2006

Creating a Bootable Windows XP Setup CD

There are a number of reasons why you may need such a CD:
  • Your copy of Windows came preinstalled, and you'd like to have a backup in case something goes wrong.
  • You want a 'slipstreamed' setup disk, i.e. a setup disk which will install XP Service Pack 2 as part of a full install.
  • You want access to the Windows Recovery Console.
I actually fall into the last category — having decided to remove Debian Linux from my computer, I also wanted to remove its boot loader, GRUB, and replace it with the Windows boot loader. Unfortunately, this can only be done using the fixmbr program which comes with the Windows Recovery Console!

If you already have a Windows Setup CD, then all you need to do is to follow the instructions given in Paul Thurrott's web site. However, if you have a preinstalled version of Windows, you may find that the contents of the Setup CD are located somewhere on your hard drive. In my case, (with an Acer TravelMate 4151LMi) the Setup files are in C:\i386. You need to follow the instructions in Bart Lagerweij's web site to create a bootable CD from the Setup files.

If you have SP2 then you'll also need to 'slipstream' the Service Pack. Unless you already have the Service Pack file, you'll need to download it from Microsoft. Instructions for downloading and slipstreaming are given as Steps 2 and 3 in Paul Thurrott's web site (you need to modify the instructions a little to work with Bart's procedure).