May 2008
jQuery and SVG
Submitted by mmorsi on Wed, 2008-05-21 16:42Both the jQuery library (as well as javascript in general) and SVG are technologies I've really been meaning to explore as a web developer. Recently at Red Hat we've been very busy overhauling our project for an impending major demo (blog post on this in the near future) and I've been expirementing with incorporating both these technologies into the site. Both are very cool, and alot can be written about them, but I'll skip all the introduction and give simply jump into how you can utilize the jQuery SVG Plugin. Before you begin, make sure you have the jquery, jquery.svg, and jquery.svggraph plugins readily available and accessible from your web page (for those using Drupal out there, it now has built in jQuery support, so you will only have to d/l the svg and svggraph plugins and insert them into your theme template). Also make sure to note that while SVG works out of the box in Firefox, IE users will need to download a plugin to get it working.
Backups Via Dirvish
Submitted by mmorsi on Tue, 2008-05-20 02:10Dirvish is an easy to use backup system based on rsync. Having recently setup an external encrypted usb drive to store backups, mounted at /mnt/backup1, I setup backups for target directories on my local system using Dirvish (of course, if it were not in early development, I would use Snap but alas its too early to trust critical system operations to it). The entire process is fairly easy, there being two files which you need to modify, as well as creating a cron job to run dirvish daily. I'll keep it brief and simple here, use this great guide if you want more info. Before we begin, recognize a 'bank' is a directory where multiple vaults are stored. A 'vault' holds the configuration and the actual snapshots of the filesystem(s).
Accessing an encrypted partition
Submitted by mmorsi on Thu, 2008-05-15 23:55A few months back I wrote an article on how to create and access an encrypted hard drive in Linux. Recently I've been setting up a large external usb drive to store nightly backups and couldn't figure out how to load the unencrypted device /dev/mapper/enc from the encrypted device /dev/sda1 post-boot (eg the usb drive wasn't turned on until the computer was completely started up). Lo and behold the answer was right in front of me, in my very own article, eg. step 3 or running the cryptsetup command:
cryptsetup -c aes-cbc-plain -d /etc/enc-key create enc /dev/sda1
I was under the impression that this altered the drive somehow, but does not in any way, it merely loads the unencrypted partition, from which point the user can mount the filesystem. I suppose a warning should go here, because I presume its possible (tho I have not tried it) to load the encrypted partition with a different key and thus the unencrypted partition will be "illegible", eg. the computer thinking its just random data. Any reads or writes to it will most certainly destroy any stored, encrypted information.
Anywho, it took me a little while to figure this one out, so I figure it might be useful for anyone else in the same situation.