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Making My Own Desktop Manager: Starting at the Beginning

The hardest part of this whole project is the lack of people talking about X Window Managers. There are countless forums post for people asking how to start learning about Window Managers and either get no response or someone just says "read the source code of {insert open-source window manager here}".

While, as a programmer, I probably agree with learning from others' source code; but I also think there is a big gap of information missing from this equation. There are plenty of high-level explanations of the roles of Window Managers and there is source-code. That's about it.

So just to clarify, here are the roles my Window Manager will be responsible for:
  • Listening for events on the root window and all child windows
  • Size and placement of windows when they are first created
  • Show the difference between the focused/active window and all other windows
  • Iconified/Hidden states of windows
  • Resizing windows
  • Moving floating windows
  • Window decoration (If I choose to go down this route?)
  • Launching programs

I decided the next phase would be to write the simplest possible Window Manager. This window manager would allow programs to accept the programs preferred location & size and would also draw a white border around the focused/active window.

The code for this example can also be found in 'simple-wm' in my GitHub project-sandbox. (Including the MakeFile)

#include <X11/Xlib.h>
#include <stdio.h>

#include <stdlib.h>

static Window focused_win;

int handle_xerror(Display *dpy, XErrorEvent *ee) {
   int i=0, alen = sizeof(ee) / sizeof(XErrorEvent);
  for (i=0; i
<alen; i++) {
    fprintf(stderr, "An error occurred: %d\n", ee[i].error_code);
  return 0;

int main()
  printf("opening display\n");
  Display *d = XOpenDisplay(NULL);

   printf("grabbing default screen\n");
  int screen = DefaultScreen(d);
  printf("default screen = %d\n", screen);

  printf("grabbing root window\n");
  Window root = DefaultRootWindow(d);

  // tell root window you'll be capturing it's events
  XSetWindowAttributes a;
  a.event_mask =   StructureNotifyMask|SubstructureNotifyMask|EnterWindowMask|LeaveWindowMask;   // root + child (sub) windows created, window-in, window-out
  XSelectInput(d, root, a.event_mask);

  // handle errors

  // capture those events
  XEvent e;

  // main event loop
  for (;;) {
    XNextEvent(d, &e);

    if (e.type == CreateNotify) {
      printf("Event: create\n");
      XSelectInput(e.xcreatewindow.display, e.xcreatewindow.window, a.event_mask);
      XSetWindowBorderWidth(e.xcreatewindow.display, e.xcreatewindow.window, 1); // always set border to 1px

    else if (e.type == ConfigureNotify) {
      printf("EVENT: configure\n");

    else if (e.type == EnterNotify) {
      printf("EVENT: focus-in\n");
      focused_win = e.xcrossing.window;
      a.border_pixel = WhitePixel(e.xcrossing.display, screen);
      XChangeWindowAttributes(e.xcrossing.display, focused_win, CWBorderPixel, &a);

    else if (e.type == LeaveNotify) {
      printf("EVENT: focus-out\n");
      a.border_pixel = BlackPixel(e.xcrossing.display, screen);
      XChangeWindowAttributes(e.xcrossing.display, e.xcrossing.window, CWBorderPixel, &a);
   return 0;

To see this window manager in action you will need to edit your .xinitrc file to launch and wait for an xterm and run the window manager form here. I realise I could launch the window manager from .xinitrc as a background process, but I want to watch the events as they happen from my logging in the host xterm shell.

So I:

  • Edited the .xinitrc file for my wmtest user (click here for my .xinitrc file)
  • Logged in as that user via SLiM
  • Started simple-wm:
    • $ /path/to/simple-wm/program&
  • Then launched another terminal window on the other side of the screen:
    • $ xterm -geometry 50x50+500+500

Notice how I didn't need to do anything in the code for the xterm window to position correctly at x=500,y=500 and size of 50charsx50chars? If you don't change the values on the ConfigureNotify event, the client window's hints are accepted! Now when I hover over the xterm window, I get a white border! Hover out and the border goes black! :)

To exit the session just type exit on the xterm shell.


mysqldump: error 29 - TEMP SOLUTION

On MYSQL DB with LOTS of tables, you might run into an error with 'mysqldump':

    mysqldump: Got error: 29: File .....


    Add --skip-lock-tables to your command

System: CentOS 64bit with MySQL 5.0.45-log

Malware found on brand new Windows netbook ...

Security vendor Kaspersky Labs found malware on new Windows XP netbook, just out from the factory. The firm is warning users to take extra precautions, and ensure virgin systems are malware free before connecting them to the Internet.

 If You is owner a netbook - be attention ...

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nmap: checking port listening in one subnet

nmap -vv -p 23

 example above is checking any listening port for telnet in subnet


Config NIS Server/Client on CentOS 5

I created two VMs via VirtualBox, named CentOS_Srv and CentOS_Cli with the IPs and, networking type is bridged.

 1. ENV

OS: CentOS 5.3

Software: ypserv, yp-tools, ypbind, etc

NIS Server:

NIS Client:

2.  Steps

1) Config NFS in the NFS server (use the NIS Server here)

[root@glynnsrv]vi /etc/exports, add the following line:

/home  *(rw,sync)

this allow  all host to mount /home as writable.

2)Make effective

[root@glynnsrv] exportfs -a

3)Start NFS server

[root@glynnsrv]service nfs start

4)Let nfs start when boot

[root@glynnsrv]chkconfig nfs on

 5)Config the firewall


select firewall settings and add NFS service.

6)Config the NFS client

[root@glynn]mv /home /home.bak

[root@glynn]mkdir /home

[root@glynn]vi /etc/hosts localhost localhost glynn glynnsrv

[root@glynn]mount -t nfs glynnsrv:/home /home

Let autofs mount the nfs at boot time:

[root@glynn]vi /etc/auto.master # add the following line:

 /home      /etc/auto.home  --timeout 600

[root@glynn]vi /etc/auto.home # add the following line:

  *    -fstype=nfs,r2

 [root@glynn]chkconfig autofs on

 7) Config NIS Server

a) install needed softwares:

[root@glynnsrv] yum -y install ypserv ypbind yp-tools

b)vi /etc/sysconfig/network




PSA: Warning, Phishers have arrived!

Two nights ago, I checked my inbox. I had a message from a user named "Izzy". Upon opening I discovered its noting but an evil phishing plot. Here is the contents of the message:

Dear Friend, I know that this is an unusual platform for us to be discussing this Kind of business but the situation has necessitated me to use this Medium to communicate you for now. But let me introduce myself to you. I am Miss. Elizabeth Mark, the manager of bill and exchange at the foreign remittance department of my Bank. In my department I discovered an abandoned sum of US$14.5M, (Fourteen Million, and Five Hundred Thousand US Dollars) at our head office Accra Ghana, that belongs to one of our foreign customers, who died along with his wife and only son in a plane crash of Alaska Airlines Flight number 261 which crashed on 31 January, 2000. The owner of this account is Mr. Morris Thompson an American and great industrialist and a resident of Alaska. It is therefore upon this discovery that I now decided to make this Business proposal to you and for our bank to release the money to You, for more detail send me an email in my private email address( This e-mail address is being protected from spambots. You need JavaScript enabled to view it or This e-mail address is being protected from spambots. You need JavaScript enabled to view it ) Yours truly, Miss. Elizabeth Mark.

 If you see something like this in your Inbox or Email please discard it. It's a scam. 


On Being a Female Computer Nerd

Sometimes when attempting to explain Linux to friends or family members who are not computer or tech-savvy, I find myself "dumbing down," as much as I'm able to, the explanations I give. Look, I say patiently. There's no green start button. Linux computers don't get infected by viruses. Our systems are inherently more secure than Windows, and don't require you to surrender personal information to use. The reason Internet Explorer on Windows is so slow and insecure is because it tracks all of your personal information, all the time. Linux doesn't do that.

Being a female computer nerd is tough

Being a female Linux nerd is even tougher.

 First and foremost, when asked to explain something technical about an operating system, I'm almost always handed the most incompetent people. A couple of months in a "tech support" position answering telephones proved that. For the short while I was an employee of an ISP, some fairly friendly customers always requested to speak to me directly: old ladies, on-site "engineers" of rival providers and even co-workers would request my input about specific technical problems. The problem with my job (which I loved, minus the telephone part) was that it was in Utah, a place that historically treats women as "less than" men.

As a female techie, I can honestly say that our pay is less commiserate.  Our hours are more demanding. Our challenges are all in all, tougher.

Being in the land of Utah, the questions I received were always all about the Microsoft operating system. Yet. . . Microsoft has never paid me a dime for all of their dollars of profit.  Even after I applied to work there (dear Linux community, please forgive me; it was a long time ago).

And to this day, I still don't have an official employer. Along this path which has been riddled with frustration, I actually now choose to consciously shun employers who require "Microsoft" competence as part of a job description. As in "Microsoft ____" AKA Microsoft (Anything). Especially Excel. It's just not necessary. Being a female computer nerd is tough. Somewhere and some how, we need to erase this stereotype, and open up the idea of computing as being something *more* than Microsoft-based or hyped Apple marketing. 


Synchronizing console sessions

Some time ago i found `screen` utility.  With it you can synchronize input and output from two or more console sessions, e.g. for remote illustrations of something.

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Hello, I'm a Linux cheerleader

On another site I write for I was recently called "nothing more than a Linux cheerleader". To that I had to respond with a "You bet I am!" How can you not call me that? I am currently wearing a Ubuntu tee shirt. I have the following tattoos on my right arm:

  • Tux penguin
  • Ubuntu Logo
  • Red hat logo

I will soon be adding to that the Enlightenment logo which will be followed by even more Linux logos.  I make no bones about it, I am proud of my operating system. I am proud of the fact that, for the last ten years I have served the Linux community as a voice and cheerleader from the side of the media. Why? The media has always been a fickle beast. Half of the media see themselves as destroyers of those they write about. They love to criticize so to pump up their own egos. The other half of the media vacillate from one side of the fence to another. Not me. My stance on Linux has only grown more fire over the years. 

Does that mean I am not critical? No. When necessary I am. I am not blind. I have come across my fair share of worthless open source software. But for the most part Linux has always worked for me - not against me.

But this isn't about's really about YOU. 

How many times have you read anything about "market share" and just rolled your eyes? I can't even tell you how many times this has happened to me. Microsoft (and members of the media inside of MS's pockets) is really keen on shoving it  down the throats of the open source community that they own the market. I have a different view of this.

Microsoft owns the consumer market. This is simple math. Proportionally, very few users pay for Linux. Because of this it's impossible to keep track of the numbers. How do I count for only 1 user when I download a single ISO and load it on five PCs and then hand that disk over to someone else who will do the same? 

If I had to make a guess I would say the realistic view of per-machine installations is probably more equal than not. I am staring five machines right now that all have Linux. In my household there are 7 machines running Linux, two machines running OS X, and one running Vista (only because I have to cover Vista for another site.) I bet if we polled the whole of the numbers would be staggering how many Linux installations there are.

To that end there needs to be some sort of system put into place to count Linux machines. I don't know the answer to this but it could look something like this:

Every time Linux is installed the final step is for the OS to send a simple packet to a centralized machine that keeps track...say the Linux counter. Instead of needing user intervention just have it happen automatically. I'm sure every distribution would be more than happy to implement this because it would give a more realistic view of what is happening with regards to installation numbers.

What do you say? Is this possible? Should this be implemented? I say GO TEAM GO! But then I am nothing more than a Linux cheerleader. ;-)


The beginning

Hello everyone!

Let me introduce myself. My name is Matt, and I enjoy learning and having fun. I will use this blog to tell everyone about my first-hand experiences with Linux as an end-user. I will try to be in-depth and informative at all times, also I would very much appreciate any comments you have. :) 


Feel free to contact me at anytime about anything via any method in my profile.




Hello Everyone!

Hey Everyone! I'm Thomas. Uhh...yeah read my about me section if you want to know more about me haha.
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