http://wiki.chkuo.name/ 2012-02-05T06:57:00-05:00 http://wiki.chkuo.name/ http://wiki.chkuo.name/lib/images/favicon.ico text/html 2011-01-10T12:01:49-05:00 chkuo http://wiki.chkuo.name/doku.php/start?rev=1294678909&do=diff This site is an experimental wiki. I plan to use this site to organize my notes. Please see my website for contact info. Moving notice: Starting from July 2010, I will move work-related pages (i.e., bioinformatics, biology, etc) to my lab wiki. Computer * backup: My automatic backup scheme using rsync and cron * firefox_extensions: List of useful Firefox extensions * mac_os_x_applications: List of useful Mac OS X applications * mac_os_x_tips: Mac OS X tips * iphone_applications: L… text/html 2010-12-25T04:46:26-05:00 chkuo http://wiki.chkuo.name/doku.php/computer/lossless_jpeg?rev=1293270386&do=diff JPEG, or JPG, is a popular image compression format used by entry-level digital cameras. I often need to transform (e.g., rotate 90-degree) JPEG files downloaded from my camera. However, because JPEG is a 'lossy' compression format, each additional round of decompression and recompression leads to further degradation of image quality. One solution to prevent this problem is to use image manipulation programs that are capable of lossless transformation. Here are some of the programs that I use: text/html 2010-09-28T05:16:53-05:00 chkuo http://wiki.chkuo.name/doku.php/computer/backup?rev=1285665413&do=diff This is how I use rsync and crontab with some simple shell scripts to set up an automatic rotating backup system for my files. Notes References Many thanks to those people who shared their knowledge and experience on the web. * <http://www.mikerubel.org/computers/rsync_snapshots/> * <http://www.sanitarium.net/golug/rsync_backups_2010.html> * <http://blog.interlinked.org/tutorials/rsync_time_machine.html>