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Friday, April 15, 2011 review


I was hired to write a review about which purportedly blackjack practice, however I wasn't able to verify this, since the site is down (currently it is showing a default directory listing from Apache, earlier today it was showing an empty page). There is very little know about this by the usual sources, and there doesn't seem to be anything interesting on the same server (it is hard to tell if the same person owns all the domain on the server due to the "privacy protected" registration).

Now back to the idea to blackjack practice: can you really train yourself? Probably, to some extent (hey, even Kent Beck - yes, that Kent Back - has a poker training website). With regular exercise you can memorize basic strategy table (this will help you with any game, regardless if its with a live dealer or with a machine - supposing that the machine is playing fair) and then you can move to more advanced techniques like card counting or shuffle tracking. I doubt however that you can achieve a level where this would be a profitable endeavor.

Full disclosure: this is a paid review from ReviewMe. Under the terms of the understanding I was not obligated to skew my viewpoint in any way (ie. only post positive facts).

Tuesday, April 12, 2011

Booting the Linux Kernel from Grub2


Recently a good friend of mine managed to uninstall all the kernels from his Ubuntu machine (what can I say - Monday morning and no coffee is a deadly combination). Luckily he had the install CD on hand so we did the following:

  1. Boot from the CD (we had Internet connection)
  2. Mount the Linux partition and chroot into it
  3. sudo su
    cd /media/..
    chroot .
  4. Reinstall the kernel with aptitude
  5. Reboot and go into Grub2 command mode
  6. Now do the following (commands need to be adjusted to match your partition - also, tab completion works, so you don't have to guess)
    insmod part_msdos
    insmod ext2
    set root=(hd0,3)
    linux /boot/vmlinuz- root=/dev/sda3 ro
    initrd /boot/initrd.img-2.6.38-6-686

It seems that most of the examples on the 'net are for Grub 1 and little is out there for Grub 2. I found the following three: How to use Grub2 to boot Linux manually, The Grub 2 Guide, GRUB 2 bootloader - Full tutorial. Also, I didn't perform steps 4-5 because he just reinstalled Ubuntu (it was a fresh install anyway), but I tried it out separately on my laptop and it works.


Monday, April 11, 2011

The wrong time to update software...


is when the user is the busiest, for example when s/he just started your application. See for example the screenshot below with Adobe Air (click trough to see it in its full beauty).

The mistakes it makes:

  • It tries to do the update when I'm trying to start Grooveshark (it interferes with my intention)
  • It consumes 100% of a core by polling for the presence of running applications (I suppose), effectively obliging me to do the update. This is combined with frequent releases (which otherwise would be a good thing) for maximum annoyance.
  • Although you can't see it in the screenshot, the updater has (had?) a bug when it asks for your sudo password: if you misstype it at first, then it asks for the root password (which doesn't exists under Ubuntu by default) and then it just gets into some weird state until the next update is released.

To sum it up: You should download and install the updates in the background (in a separate, versioned directory, always keeping just the two most recent versions). Users shouldn't be bothered with this, especially when they are trying to get work done!

Sunday, April 10, 2011

Recovering encrypted home directory under Ubuntu


While the home-folder encryption in Ubuntu is far from a perfect solution (there is considerable data leakage from the swap file and the temp directory - for example once I've observed the flash videos from Chromium porn private browsing mode being present in the /tmp directory), it is a partial solution nevertheless and very easy to set up during installation. However what can you do if you need to recover the data because you fubard your system?

Credit where credit is due: this guide is taken mostly from the Ubuntu wiki page. Also, this is not an easy "one-click" process. You should proceed carefully, especially if you don't have much experience with the command line.

  1. Start Ubuntu (from a separate install, from the LiveCD, etc) and mount the source filesystem (this is usually as simple as going to the Places menu and selecting the partition)
  2. Start a terminal (Alt+F2 -> gnome-terminal) and navigate to the partitions home directory. Usually this will look like the following:
    cd /media/9e6325c9-1140-44b7-9d8e-614599b27e05/home/
  3. Now navigate to the users ecryptfs directory (things to note: it is ecryptfs not encryptfs and your username does not coincide with your full name - the one you click on when you log in)
    cd .ecryptfs/username
  4. The next step is to recovery your "mount password" which is different from the password you use to log in (when it asks you, type in the login password used for this account - for which you are trying to recover the data). Take note of the returned password (you can copy it by selecting it and pressing Shift+Ctrl+C if you are using the Gnome Terminal)
    ecryptfs-unwrap-passphrase .ecryptfs/wrapped-passphrase
  5. Now create a directory where you would like to mount the decrypted home directory:
    sudo mkdir /media/decrypted
  6. Execute the following and type in (or better - copy-paste) the mount password you've recovered earlier
    sudo ecryptfs-add-passphrase --fnek
    It will return something like the following. Take note of the second key (auth tok):
    Inserted auth tok with sig [9986ad986f986af7] into the user session keyring 
    Inserted auth tok with sig [76a9f69af69a86fa] into the user session keyring
  7. Now you are ready to mount the directry:
    sudo mount -t ecryptfs /media/9e6325c9-1140-44b7-9d8e-614599b27e05/home/.ecryptfs/username/.Private /media/decrypted
     Passphrase:  # mount passphrase
     Selection: aes
     Selection: 16
     Enable plaintext passthrough: n 
     Enable filename encryption: y # this is not the default!
     Filename Encryption Key (FNEK) Signature: # the second key (auth tok) noted
    You will probably get a warning about this key not being seen before (you can type yes) and asking if it should be added to your key cache (you should type no, since you won't be using it again probably).

That's it, now (assuming everything went right) you can access your decrypted folder in /media/decrypted. The biggest gotcha is that home/username/.Private is in fact a symlink, which - if you have an other partition mounted - will point you to the wrong directory, so you should use the home/.ecryptfs/username directory directly.


scentsy review take two


I've already written about Scentsy Products, so I will try not to repeat myself that much (other than reiterating that you should really think before investing in a referral system) and will focus on their special product:

Piece by Piece Full-Size Scentsy Warmer – this a usual warmer (usual for Scentsy that is – it uses a lightbulb to provide the heat, thus avoiding the open flame and smoke) with a puzzle-piece decoration. What makes this item (more) special is the fact that parts of the revenue from it go to Autism Speaks. While currently this is the only one in the Charitable Cause Warmers product line, hopefully there will be more in the future, allowing you to get something for both your body and your soul.

An other item I didn’t talk about in the last article is the gift certificate: if you consider appropriate, you could give a 25 USD Gift Certificate to the person. There are also replacement parts and individual warmer parts if your warmer breaks but you don’t want to buy a completely new one. Also, the light bulbs in the Scentsy products are standard ones (compared to something like a Philips wake-up light) so you can buy a replacement in almost any store, as long as you watch for the socket size and the wattage.

Full disclosure: this is a paid review from ReviewMe. Under the terms of the understanding I was not obligated to skew my viewpoint in any way (ie. only post positive facts). review


There isn't much I can say about this company. They seem very legitimate by all indications (domain name registered more than 10 years ago, with the physical address of the company, no complaints on the web, etc). Their goal seems also very laudable: creating playground surfacing out of recycled tire rubber. While I don’t have enough information to ascertain if this is truly more eco-friendly than getting rid of the tires in other ways (burning them for example – there are many factors here – the recycling process itself might consume a larger amount of energy – see a similar issue with the fact that placing solar panels in the Sahara desert might actually increase global warming), reusing is always a laudable goal.

The company is also relatively media-savvy: they have a (Facebook) like button on their website, they have a blog and their site is relatively nice looking (even more important: it doesn’t look like one of the stock templates from designers). The only thing you can’t do is to order online, but probably it’s better this way, since we are talking about relatively large amount of material (and automatically large amount of money) so a personal contact is a better option. Also, I didn’t see any indication that they ship outside of the USA, probably for the same reason.

Thumbs up for a small-medium business which has a good product!

Full disclosure: this is a paid review from ReviewMe. Under the terms of the understanding I was not obligated to skew my viewpoint in any way (ie. only post positive facts).

Friday, April 08, 2011 review

Today I'm reviewing a site which has the goal of comparing different private health insurance companies and giving you the cheapest one. Unfortunately I'm not familiar with the USA insurance rules (because I'm on a different continent :-)), so I can only comment on generic impressions related to this site:
  • The domain was registered in 2007, which is reassuring, however the registration information is hidden, which raises some questions, especially given the fact that you are supposed to trust this site with personal data (like address, phone number, date of birth, name)
  • The design is ok, although there are some technical glitches (like using the sitemap link to give the sitemap for the search engines, although this wouldn't be necessarry - there are other ways to point the search engines to it)
However the biggest downfall of the site is the confusing interaction model and stale data: when you request a free quote it asks you a lot of personal information (then again I don't know how much data the individual insurance companies risk model needs) in a separate popup. It presents the result in both the popup window (however both links it gave me gave me an 404 error) and also the main window, but clicking trough the main window requires to fill the form again.
In conclusion I have a low confidence level that such comparison sites would be a reliable information source and also the comparison on price alone isn't enough when making such an important decision.

Full disclosure: this is a paid review from ReviewMe. Under the terms of the understanding I was not obligated to skew my viewpoint in any way (ie. only post positive facts).