Dropbox: online folder to easily sync your data across different computers

Like many users, I regularly use more than one computer: one at home (a Mac) and one at work (Linux workstation). This kind of situation creates some challenges regarding how to keep your data synchronized between the different computers/operating systems.

That's where the free online service Dropbox comes handy. It creates a local folder called Dropbox in your "home". Everything that you dump in that folder is automatically synced with the online folder, and immediately made available to all your computers. You just need to install a dropbox client in each computer, and that's it. Thanks to Dropbox, I almost don't need to use USB flash drives anymore to sync data between different computers. Sweet!

Dropbox has a cool feature: it lets you share a folder among a group of people. Let me give an example of how that can be useful. Suppose you have coworkers/collaborators and you are working together on some code, paper or data. Suppose that you are constantly updating your code/paper/data and your collaborator wants to always have the latest version of it. When you share a dropbox folder with your collaborators, every change that you or your coworker make to any file in that folder is automatically made available to all the people sharing the folder. See how the sharing feature can be useful?

Dropbox gives you a free 2 GB account. For paid accounts, they provide more space (up to 100 GB).

Link to join Dropbox (includes a tour of the features).

Changelog:

• May 31 2010: Added "sharing" feature.
  

Recovering deleted pictures from a memory card

A friend of mine recently deleted by accident around 700 pictures from a memory card in her Sony digital camera. She asked for my help and I thought that it would be an easy task to recover the pictures. I played with different programs aimed at data recovery, some of them tuned specifically for photo recovery. Here is a description of the different programs that I used and the results.

I've got several suggestions from colleagues of recovery software to try in linux and windows. I also found that this list of free data recovery programs at lifehacker was very useful.

This tutorial assumes that the memory card is formatted with the filesystem FAT16 (default filesystem in memory cards). The first thing you need to avoid is to write any data to the device where the deleted files were stored.

You should create an image of the device as soon as possible, in case anything goes wrong. In Linux that is pretty easy. Assuming that the memory card is mounted as /dev/sdb1, you need to issue the command
sudo dd if=/dev/sdb1 of=backupcard.img

I tried the following free software (ordered according to my taste): Recuva (win), recoverjpeg (linux/mac) and PhotoRec (win/linux/mac) (recoverjpeg and PhotoRec are available in Ubuntu via Synaptic). I also tried the commercial alternatives Stellar Phoenix Recovery (win) and Nucleus Kernel FAT (win). The latter two programs gave the same results as the three free programs listed above, so no need to pay for them.

The first program I tried was Recuva. It immediately recovered all the deleted files. Unfortunately most of the recovered pictures were corrupted or broken. By corrupted I mean that the pictures have one or more of the following "features":

• Pictures split in two or more parts
• In between a picture there is part of another photo
• Colors changed

I would say that only 1/7 of the deleted pictures were successfully restored, and the rest had the problems specified above. I tried to fix these problems using JPEG Recovery (win), which allegedly would fix the corrupted pictures but got no success.

recoverjpeg gave the same results as Recuva: restored all the photos, but only ~1/7 of the original files were successfully recovered with no problems.

PhotoRec only recovered the ~1/7 pictures that had no problems, ignoring the other corrupted files.

My conclusion: if you use windows try Recuva. If you are a Linux user, try recoverjpeg. And please check this list of Five best free data recovery tools.

Liberar espaço desperdiçado pelo Windows Vista

Galera, descobri que o Windows Vista usa um monte de espaço do seu HD para armazenar cópias de arquivos (shadow copies na terminologia deles) e pontos de restauração, potencialmente 20% do tamanho do HD. No meu caso, o meu laptop tem uma partição de 130 GB de espaço separada para o Vista, e descobri que o vista estava reservando 21 GB (!!!) para gravar pontos de restauração e shadow copies. Exagero.

Para remediar isto, acesse este link. O comando
vssadmin list shadowstorage
lista o espaço que o system restore está usando. O comando
vssadmin Resize ShadowStorage /For=C: /On=C: /Maxsize=3GB
reajusta o tamanho alocado para o system restore. No meu caso, eu separo um espaço de 3 GB para os pontos de restauração. Dá até pra desativar os pontos de restauração automáticos, mas eu não recomendo isto.

Pronto, espaço milagrosamente liberado no HD!