Category Archives: tips

erase free space on an SSD drive

DeleteAs you probably know (because you’re reading this post) Windows doesn’t really destroy a file when it is deleted. It merely removes the references in the file table so you don’t see it in on the file system anymore. But the file is still intact sitting there on your hard drive until some other file is written over it.
If you want to truly erase those files on a HDD drive you can use a number of tools to erase the free space on the drive. What these tools do is simply overwrite all free space with random data and thus effectively overwriting and destroying those deleted files still sitting intact in your free disk space.
Free tools that can do this are the command line Secure Delete tool from System Internals and the handy CCleaner (see the tools menu).

For an SSD drive however overwriting the free space with random data is bad for your drive. SSD’s have a limited number of times you can write data to their blocks. Using a random data overwrite tool, which can even end up do this multiple times, is just a bad idea.

Luckily everything is built into your SSD drive to do this automatically. It’s called the TRIM function and from Windows 7 on this is activated by default so normally you don’t have to do a thing to take advantage of this secure-delete feature.

However if you are like me then you want to be sure if this feature is activated.
On Windows, you can do this by opening a command prompt and entering the following command:

fsutil behavior query disabledeletenotify

If you get the following, your TRIM command is already active on Windows:

NTFS DisableDeleteNotify = 0

If this would return a value of 1, you can activate the TRIM function with this command:

fsutil behavior set DisableDeleteNotify 0

You can find more detailed instructions and information about activating the TRIM function here:
How to check if TRIM is enabled on your SSD and how to enable it
Why SSD TRIM support is so important and how to enable it

And then there’s always Google of course.

disable flash and silverlight for safer surfing

Flash, Silverlight and (*gasp*) QuickTime plugins in your browser with the modern web are about as necessary as a horse whip is on a Tesla. Well I might be exaggerating a bit. There are still some useful sites out there that actually use these things. Intranet sites that run on IE only for example, or flaky game sites. But any self-respecting web developer has long ditched them in favor of fancy new HTML5 features.

So why would you still run these things in your favorite browser (Firefox right?) where they only take up extra memory and have a bunch of security problems that might end up causing you trouble. There have been enough exploits for the Flash plugin out there to be sure to actually update those plugins every time they ask for it. Which is about every week if I recall correctly.

Anyway, it’s better to turns those damn things off completely and only turn them on when you hit one of those web sites maintained by a dinosaur. That way you’re stopping that evil hacker from taking over your machine with his Flash exploit and you’re gaining some free performance along the way.

In Firefox you can turn those plugins off in your Tools menu, under Add-ons. Just select “Never activate” and you’ll be fine.
Switch it back to “Ask to Activate” if you’d need them again. That way they’ll never activate by accident either, if you forget to turn it back off.
On Chrome it’s a bit more elaborate, but the option “Let me choose when to run plugin content” sounds like a safe bet instead of having plugin code be ran willy-nilly.
IE? Ha! Who cares right?! For anything else, a properly aimed search query should find you the answer in no time.

Oh, and don’t forget to tweak your Flash security settings if you decide to keep it on after all.

The Firefox add-in screen with all plugins disabled. Just like it should be.

ip-cam considerations

Security Camera SystemsIP cams are great. They keep an infrared eye on your stuff while you’re not around and find out what keeps pooping on your driveway (a cat it turns out). But sometimes things can get a little out of hand.

So here’s a list of things that will trigger the IP cam motion detection you didn’t think of:

  • Cats parading on your driveway like they own the place.
  • Spiders shaking their arachnid booty in front of the camera while doing their webbing thing.
  • Spider webs moving in the wind, up close. All f-ing night.
  • The occasional bird.
  • The occasional insect in mid-flight. Sometimes even a mot at night caught in the infrared beams.
  • Trees and bushes shaking their leaves and branches cause it’s windy as hell.
  • Shadows of trees and bushes shaking their leaves and breanches because it’s windy as hell and sunny too.
  • Rain showers. Possibly in combination with freaky winds blowing it horizontally in places you didn’t think rain could get at.
  • The sun playing peekaboo with some clouds, causing abrupt changes in light levels.
  • Car headlights lighting up random bushes, walls and other stuff as they pass by your house.
  • Reflections of cats in the cars shiny exterior (what a great excuse for not washing your car).
  • Reflections of moving clouds in a puddle on the concrete at the right lighting conditions.

So watch out where and how you send those automated alert emails from the camera. GMail for example doesn’t like it when you send hundreds of emails a day using one account. They find it rather spammy. When this happens, they can block you from sending any more messages that day. This really blows if you have an urgent mail to send. Other mail providers have similar rules.
Uploading the images to a remote FTP server is another option. But make sure you have plenty of space there, and download those images regularly if you don’t want to run out of space.

Photo by Armend Krasniqi, cc-licensed.

warmup your site or wordpress blog with a single command line statement

mother

GNU Wget is a powerful tool when it comes to downloading files from the web or mirroring sites. It’s command line features can be daunting and not very obvious. With some experimentation, reading the (f..) manual and some Googling you can get it to do some pretty neat tricks for you.
All of that is from the command line too, which is great if you want to schedule this kind of magic or use it in a script.

For example, you might want to warm-up your site or WordPress blog so your homepage and all posts linked from it are present in your cache when a visitor arrives. I’m assuming you are using a caching on your site otherwise this is pretty pointless. For WordPress you can use a caching plugin like W3 Total Cache for example.

With Wget, it goes like this:

wget.exe http://n3wjack.net --spider --no-directories --level=1 --recursive 
         --accept-regex=n3wjack.net/20[1..9].*

The command line parameters (in order) mean something like:

  1. Crawl n3wjack.net.
  2. Crawl it like a spider (follow the links).
  3. Don’t create directories for downloads.
  4. Crawl 1 level deep (so anything linked on the homepage is OK, but don’t go deeper).
  5. Do this recursively (so it actually goes 1 level deep).
  6. Follow only links that start with "/201..." to "/209..." (it’s a regular expression).
    This one is a trick to have it only follow links to blog-posts because my URL scheme begins with the year of the post (2015, 2016, …). It’s good until 2099, which should do the trick I guess. :)
    This way I’m also avoiding it loading all tag, category or page links.

If your site has a different URL scheme you’ll have to change the accept regex pattern to fit your scheme.

You can download Wget from the GNU site. It’s Open Source and is available for Windows, Mac and various Unix systems.
For Chocolatey users, there is a wget package available to install it on your system.

verifying an md5 file hash with just powershell

Tools
You see this possibility for a lot of software downloads but if you’re like me you hardly ever end up doing it: verifying an install file’s MD5 or SHA-something hash.
For Open Source software this is however recommended if you aren’t downloaded from the official mirror (and even then) and certainly if it’s anything related to security (like Keepass for example).

But to verify that MD5 hash you probably need to install yet another piece of software you’re hardly going to need, so you end up not bothering at all.

Hold on a second.

If you have a recent Windows system with PowerShell installed, you probably have all you need to verify that MD5 hash.

Try this in the PowerShell command prompt:

Get-FileHash .\KeePass-2.30-Setup.exe -Algorithm md5

It should print out something like this:

Algorithm       Hash
---------       ----
MD5             CD430EB0F108BB192D2155C68EB7BB48

Which happens to be exactly the MD5 hash code listed on the site for that version of the Keepass installer. Yay!
Without that -Algorithm parameter it prints out the SHA-256 hash by default, but that’s longer and harder to compare visually even though it’s more precise.

That was easy and required no additional software.
Pretty damn sweet.

Photo by Julien Dumont, cc-licensed.

how to move an unreachable window on windows 7, 8 or 10

arrowsOn the “good” old XP this required some trickery and knowledge of window specific shortcuts, but on more recent version of Windows this has become really easy to do.

So if you run into a situation where an application’s window is outside your visible area, because you disconnected a second screen for example and the app doesn’t automatically snap to the only screen left, simply do this:

  • Keep the Windows key pressed and hit the cursor key left or right.

Your window will simply snap back to your current screen and all is well.
Using it with the up & down arrow will maximize or minimize the active window. Always handy to know those shortcuts if you have both hands on the keyboard anyway.

Photo by Dean Hochman, cc-licensed.

disabling Dell software without uninstalling

Yes, a cat. Cause it's the internet after all.

You know how it goes. You get this new and shiny computer from big computer company X and with it you don’t only get your OEM licensed Windows OS but also some “super handy” tools X happened to install just for you.

Dell is no different so mine come with Dell Data Vault, Dell SupportAssist and Dell Update Service. All of this is (of course) for your own benefit to update your machine to the latest drivers and blah blah blah, even though anything crucial is sent through Windows update anyway.

The downside is that these things are constantly running and using up your precious CPU and memory, while you’ll probably never need them. Ever. Oh, and they also come with some security vulnerabilities apparently, which is always a good reason to kick their butt.

I don’t know what Dell Data Vault even does and don’t care to either (it’s backup software probably). To make things worse it even causes my system to lag sometimes which I notice as my audio glitches up when that happens. I don’t always listen to breakcore you know, so I do noticed that sometimes.

I also noticed that uninstalling Dell Data Service is pointless as (I think) the Dell UpdateService will just reinstall it. Which sucks.

So I see two options.

  1. Uninstalling all Dell related software. This is kinda drastic and you might want that stuff if you need support after all.
  2. Disable the software and prevent it from starting up altogether.

So how do you stop those services from starting up automatically? Here’s how:

  1. On you desktop, press WindowsKey-R, this brings up the Run prompt.
  2. Type services.msc and hit enter. This brings up the list of services installed on your machine.
  3. Look for the Dell ones in the list.
  4. Open them, one by one, and in the General tab select the startup type “Disabled”.
  5. Hit “OK” to save.

How to disable a service from auto-starting.Note that in the screenshot I’m disabling a completely innocent service per demonstration as I don’t have a Dell machine handy with an English version of Windows on it.

From now on those pesky services won’t be wasting your resources anymore, untill the day you might need them again. All you have to do then is go back into the services console and switch the startup type back to Automatic and save.
Then right-click the services in the list and choose “Start”, or simply reboot the machine.

But we’re not quite there yet. There’s still the case of PCDoctor and the SupportAssist client. Those sneaky startups are hidden in the scheduled tasks. You can disable them using the Task Scheduler like this:

  1. Press WinKey-R and type Taskschd.msc, press enter.
  2. In the list of scheduled tasks in the root node you’ll see a “Dell SupportAssistAgent AutoUpdate” or something similar.
  3. Right click the task and choose “Disable”.
  4. Repeat for any other Dell tasks in there.

They don’t all have “Dell” in their name, but if you check the Action tab below the path to the executable will give them away (like in the screenshot). In my case I had some additional PCD (PC Doctor) tasks and one SystemToolsDailyTest task to disable.

Another good tool to disable scheduled tasks if from the CCleaner tools menu, or by using the SysInternals Autoruns tool.The name of the task doesn't tell, but the path to the executable does indicate it's a piece of Dell software.

This worked for me, but as is mostly the case with things you find on the internet… use this info wisely and at your own risk. ;)

Photo by Massimo Regonati, cc-licensed.