Thursday, July 26, 2012

How to Create a Secretly Disguised Folder Without Extra Software


Almost anyone knows how to make a “hidden” folder in Windows, most people also know how to make Explorer show hidden folders. Instead, if your folder looked like an innocent shortcut no one would know you have data in there.

Using Command Prompt to Disguise a Folder

In this example I have an ordinary folder on the root of my drive called How-To-Geek.
To disguise it, I need to open a command prompt and navigate to the directory where its resides, since it is on the root of my drive I can use:
CD C:\
Now all I need to do is rename it and include the CLSID for Computer:
ren How-To-Geek How-To-Geek.{20d04fe0-3aea-1069-a2d8-08002b30309d}
Now if I go back to my folder it looks like a link to Computer, and if I click on it, it even opens Computer. No one can get inside this folder now without knowing the CLSID you used to hide it.

Using Command Prompt to Reveal Your Folder

You will need to navigate to the directory where the disguised folder resides.
CD C:\
Then all you need to do to unhide a folder is rename the folder back to what it was before:
ren How-To-Geek.{20d04fe0-3aea-1069-a2d8-08002b30309d} How-To-Geek
If you go look at your folder now you will see it’s back to normal.

Using Batch Files

If you want to go even one step further you can create batch files. The following one hides my folder.
Then to unhide it i use the following batch file.
All that you would need to do now is run one of the batch files.
You should also take note that although this is a geeky way of hiding your data nothing is stopping the person from deleting the folder which would delete everything you have inside as well.

Wednesday, July 25, 2012

What is a Zombie Process on Linux?

zombie processes on linux
If you’re a Linux user, you may have seen zombie processes shambling around your processes list. You can’t kill a zombie process because it’s already dead – like an actual zombie.
Zombies are basically the leftover bits of dead processes that haven’t been cleaned up properly. A program that creates zombie processes isn’t programmed properly – programs aren’t supposed to let zombie processes stick around.
Image Credit: Daniel Hollister on Flickr (Remixed)

What’s a Zombie Process?

To understand what a zombie process is and what causes zombie processes to appear, you’ll need to understand a bit about how processes work on Linux.
When a process dies on Linux, it isn’t all removed from memory immediately — its process descriptor stays in memory (the process descriptor only takes a tiny amount of memory). The process’s status becomes EXIT_ZOMBIE and the process’s parent is notified that its child process has died with the SIGCHLD signal. The parent process is then supposed to execute the wait() system call to read the dead process’s exit status and other information. This allows the parent process to get information from the dead process. After wait() is called, the zombie process is completely removed from memory.
This normally happens very quickly, so you won’t see zombie processes accumulating on your system. However, if a parent process isn’t programmed properly and never calls wait(), its zombie children will stick around in memory until they’re cleaned up.
Utilities like GNOME System Monitor, the top command, and the ps command display zombie processes.

Dangers of Zombie Processes

Zombie processes don’t use up any system resources. (Actually, each one uses a very tiny amount of system memory to store its process descriptor.) However, each zombie process retains its process ID (PID). Linux systems have a finite number of process IDs – 32767 by default on 32-bit systems. If zombies are accumulating at a very quick rate – for example, if improperly programmed server software is creating zombie processes under load — the entire pool of available PIDs will eventually become assigned to zombie processes, preventing other processes from launching.
However, a few zombie processes hanging around are no problem – although they do indicate a bug with their parent process on your system.

Getting Rid of Zombie Processes

You can’t kill zombie processes as you can kill normal processes with the SIGKILL signal — zombie processes are already dead. Bear in mind that you don’t need to get rid of zombie processes unless you have a large amount on your system – a few zombies are harmless. However, there are a few ways you can get rid of zombie processes.
One way is by sending the SIGCHLD signal to the parent process. This signal tells the parent process to execute the wait() system call and clean up its zombie children. Send the signal with the kill command, replacing pid in the command below with the parent process’s PID:
kill -s SIGCHLD pid
However, if the parent process isn’t programmed properly and is ignoring SIGCHLD signals, this won’t help. You’ll have to kill or close the zombies’ parent process. When the process that created the zombies ends, init inherits the zombie processes and becomes their new parent. (init is the first process started on Linux at boot and is assigned PID 1.) init periodically executes the wait() system call to clean up its zombie children, so init will make short work of the zombies. You can restart the parent process after closing it.
If a parent process continues to create zombies, it should be fixed so that it properly calls wait() to reap its zombie children. File a bug report if a program on your system keeps creating zombies.

Sunday, July 22, 2012

Why The Internet Is Running Out of IPv4 Addresses and Why IPv6 Is Important

IPv4 addresses on the public Internet are running low. Microsoft paid $7.5 million for Nortel’s 666,624 IP addresses when Nortel went bankrupt in 2011 – that’s over $8 an IP address. IPv4 has technical problems, and IPv6 is the solution.
Unfortunately, deployment of IPv6 has been put off for too long. Had IPv6 been implemented years ago, the transition from the older standard to the newer one would have gone much more smoothly.
Image Credit: Bob Mical on Flickr

Technical Problems with IPv4

In 1980, Internet Protocol version 4 addresses were defined as 32-bit numbers. This provided a total of 232 IPv4 addresses – that’s 4 294 967 296, or 4.2 billion, addresses. This may have seemed like a lot of addresses back in 1980, but today there are many more than 4.2 billion network-connected devices on the planet. Of course, the number of devices connected to the Internet will only continue to grow. To make matters worse, some of these IPv4 addresses are reserved for special cases, so the Internet has fewer than 4.2 billion publically routable IPv4 addresses available to it.
There aren’t anywhere near enough publically routable addresses available for every device on the Internet to have a unique one. One thing that’s helped is network-address translation (NAT), which most home networks use. If you have a router in your home, it takes a single publically routable IP address from your Internet service provider and shares it amongst the networked devices in your home. To share the single IPv4 address, it creates a local area network, and each networked device behind the router has its own local IP address. This creates problems when running server software and requires more complicated port forwarding.
Carrier-grade NAT is one solution – essentially, every computer using an Internet service provider would be on a local network specific to that ISP. The ISP itself would implement network-address translation, just like a home router. Individuals wouldn’t have publically routable IP addresses and running some forms of server software that requires incoming connections wouldn’t be possible.
Image Credit: Jemimus on Flickr

How IPv6 Solves the Problems

To avoid the future exhaustion of IPv4 addresses, IPv6 was developed in 1995. IPv6 addresses are defined as 128-bit numbers, which means there are a maximum of 2128possible IPv6 addresses. In other words, there are over 3.402 × 1038 IPv6 addresses – a much larger number.
In addition to solving the IPv4 address depletion problem by providing more than enough addresses, this large number offers additional advantages – every device could have a globally routable public IP address on the Internet, eliminating the complexity of configuring NAT.
Image Credit: Justin Marty on Flickr

So What’s the Hold Up?

IPv6 was finalized in 1998, 14 years ago. You might assume that this problem should have been solved long ago – but this isn’t the case. Deployment has been going very slowly, in spite of how long IPv6 has been around. Some software is still not IPv6 compatible, although much software has been updated. Some network hardware may also not be IPv6 compatible – while manufacturers could release firmware updates, many of them would rather sell new, IPv6-ready hardware instead. Some websites still do not have IPv6 addresses or DNS records, and are only reachable at IPv4 addresses.
Given the need to test and update software and replace hardware, IPv6 deployment has not been a priority for many organizations. With enough IPv4 address space available, it’s been easy to put IPv6 deployment off until the future. With the imminent exhaustion of available IPv4 addresses, this concern has become more pressing. Deployment is ongoing, with “dual-stack” deployment easing the transition – modern operating systems can have both IPv4 and IPv6 addresses at the same time, making deployment smoother.

The Best Websites for Watching Free Documentaries


If you’re a fan of documentaries, there are many sites where you can watch them for free. The following is a list of sites we found, some of which allow you add comments about the films and even allow you to download the films.

Top Documentary Films

Top Documentary Films offers full documentaries and information on documentaries by quoting reviews from trusted sources. The documentaries are classified in categories, making it easy to find films about your favorite topics. You can also add comments about documentaries you’ve watched, providing opinions other viewers can read about the films to see if they want to watch them.
If you find documentary films you really like, you can decide to buy them from the Top Documentary Films store. streams full-length, thought-provoking, educational, and entertaining documentary films for free, with no registration required. They have searched the web for well-produced videos and gather them onto one site. For some films, you can even watch trailers or download the film. Some films on the site have widespread distribution, but others are created by independent filmmakers, who depend on sites like to get their information out to the public.

Documentary Heaven

Documentary Heaven offers a vast collection of documentaries spanning across many genres. They continuously update the site daily to provide the very best in documentary films.


DocumentaryWIRE offers a large collection of free, interesting, and educational documentaries for you to watch online. The films cover many genres. Watch what catches your interest and share your thoughts.

Open Documentaries

Open Documentaries maintains a documentary database with a lot of documentaries for you to view for free in a lot of categories. There are no costs involved and you don’t need to register. However, you can register if you want to create your own playlist and receive email updates when new documentaries are added. There is also an option for automatically adding new documentaries to your playlist. offers a large catalog of full length, free documentaries on a wide range of topics, such as nature, politics, science, and history. You can browse by category, sort by top films, by length (short, mid, and long, which are less than 10, 11-30, and 30+ minutes, respectively), and even watch mini-documentaries about the making of the documentaries themselves. The documentaries are available worldwide, without any territory restrictions.


DocumentaryStorm offers free, full-length documentaries gathered from around the web. Their main goal is to share knowledge, spread ideas, and have fun. DocumentaryStorm adds a new documentary to their site every day. collects the best documentary films available on the web. Watch quality documentaries streaming directly in the browser without having to register.

Full Documentaries

Full Documentaries offers some of the most informative, free documentaries available online, organized into categories. You can also post comments about the films and rate them. was founded by fans of documentaries who gather the very best films from around the web. They focus on science documentaries, because this seemed to the most underrepresented genre on the web, but they also offer films covering other genres. Feel free to add comments about films you watch on their site and to rate the films, as well.

Documentary Tube

Documentary Tube offers a wide variety of full-length documentaries covering twenty-two categories, such as art, health, science, travel, and history. You can search by subject or name of documentary to see if it’s available on the site.
Documentary Tube also features the top 100 documentaries being viewed each week. There is also a section of the site that allows you to submit documentaries you produce and make yourself. These submissions are reviewed by the website’s editors to see if they would be appropriate for the site.
You can easily register for free on Documentary Tube to stay updated about new releases featured on the website. Another option is to have new documentaries sent to your feed reader via RSS feeds. You can choose to sign up for weekly email alerts, informing you weekly of new releases available on Documentary Tube. New release information is also available by liking Documentary Tube on Facebook or by following the site on Twitter. There’s also a giveaway each month for registered members.
Documentaries you’ve watched on Documentary Tube are automatically added to a playlist, so you can easily go back and watch them again, or find out what subjects and titles you have already watched. There’s also a section of the site containing articles that review some of the current documentaries, providing more information about the films. This list of articles is updated weekly.

Science Documentaries

Do you love scientific documentaries? The Science Documentaries website offers a collection of the best scientific documentaries available on the web. They focus on quality, rather than quantity. You will not find documentaries “filled with metaphysical ideas, UFOs, bio energies and other meta-sciences.” What you will find are informative, revealing, interesting, and mind-boggling scientific documentaries and lectures about such subjects as astronomy, biology, mathematics, physics, IT, and technology.

YouTube Free Documentaries

As you know, there are many videos available on YouTube, including free documentaries. These may be found on some of the other sites that collect documentaries, as well, or you can access them directly on YouTube.

IndieMovies Online

IndieMovies Online is dedicated to the free, legal distribution of independent films. In addition to watching quality independent films, IndieMovies Online also encourages you to write for them, by submitting a copy of your piece (no more than 700 words and nothing offensive). The piece will be reviewed, and, if it adheres to the basic guidelines and criteria, it will be posted in the guest writers’ section of the site. This promotes meaningful, articulate, and informed discussions about film.
They also plan to support independent film at its roots by showcasing the work of film students around the world. They have been inviting film students from all schools to submit their work to be shared on IndieMovies Online.

Documentary Guide

Documentary Guide is one of the few curated search engines on the internet and offers access to the widest collection of documentary films. They’ve researched and indexed thousands of films, hundreds of websites, and many databases from around the world. The films have been organized and tagged and sifted through for education and awareness.

Internet Archive – Moving Image Archive

Yet still another place to find documentaries is the Moving Image Archive on the Internet Archive website. This site contains thousands of digital movies uploaded by Archive users. There are probably some documentary films among the collection that might peak your interest.
Hopefully, this list helps you find free, educational, and entertaining documentary films that interest and inspire you. If you know of other good sites for finding free and legally distributed documentaries, let us know in the comments.

Sunday, July 15, 2012

How to Make Your PC Wake From Sleep Automatically


When you put your PC into sleep mode, it normally waits until you press a button before it wakes from sleep – but you can have your PC automatically wake from sleep at a specific time.
This can be particularly useful if you want your PC to wake and perform downloads in off-peak hours or start other actions before you wake up in the morning — without running all night.

Setting a Wake Time

To have the computer automatically wake up, we’ll create a scheduled task. To do so, open the Task Scheduler by typing Task Scheduler into the Start menu and pressing Enter.
In the Task Scheduler window, click the Create Task link to create a new task.
Name the task something like “Wake From Sleep.” You may also want to tell it to run whether a user is logged on or not and set it to run with highest privileges.
On the Triggers tab, create a new trigger that runs the task at your desired time. This can be a repeating schedule or a single time.
On the conditions tab, enable the Wake the computer to run this task option.
On the actions tab, you must specify at least one action for the task – for example, you could have the task launch a file-downloading program. If you want to wake the system without running a program, you can tell the task to run cmd.exe with the /c “exit”arguments – this will launch a Command Prompt window and immediately close it, effectively doing nothing.
Save your new task after configuring it.

Putting The Computer to Sleep

Put the computer to sleep using the Sleep option instead of shutting it down. The computer won’t wake up if it’s not in sleep mode. You can also change Windows’ power saving options to have the PC automatically sleep after it hasn’t been used for a while or when you press specific buttons.

Thursday, July 12, 2012

How to Map Network Drives From the Command Prompt in Windows


You most probably know how to assign a drive letter to a network share, but that’s not impressive. Why not change that by mapping your network shares from the command prompt?

Mapping a Network Drive in Windows

To map a network drive from the command prompt we have to use the net use command. If you already know the UNC path to your share, then you’re good to go–the following command will map the movies share to the S drive.
net use s: \\tower\movies
Your share will probably be protected with some sort of authentication, and the user switch allows us to specify a username and password. The following example assumes:
  • The username you authenticate with on the remote machine is HTG
  • The password for the HTG account is Pa$$word
net use s: \\tower\movies /user HTG Pa$$word
The previous commands are not persistent, this means that the minute you reboot your PC the shares will disappear from your computer. To get the shares to survive a reboot, you need to add use the persistent switch. Note that you can also just use /P instead.
net use s: \\tower\movies /P:Yes
If you ever need to delete a mapped network drive, you can use the delete switch after specifying it’s drive letter.
net use s: /Delete
Alternatively, if you ever want to get rid of all the shares on your machine, you can use the wildcard character instead of specifying a specific drive letter.
net use * /Delete
That’s all there is to it.

Tuesday, July 10, 2012

Do You Really Need to Safely Remove USB Sticks?