Wednesday, May 30, 2012

Happy 5th, Firefox And USB Progress

We were working on future budgets and were reminded again about the great savings obtained with running thin clients.  It was just about 5 years ago that our thin clients arrived and they are still working great.  We only have been losing maybe about 5 or so a year due to hardware failure since the 3 year warranty expired.   Right now it appears we can get another 5 years of duty.  $400 / 10 years for around a $40 dollar a year physical hardware desktop cost; and they still are very rarely touched by IT staff.  This architecture really does work and really does save lots of money.

We had a very odd situation where HTML 5 videos were only working for my user account and root.  I knew at that point it must have been some kind of file permissions issue.  After some poking around with strace, I found it in /tmp

drwx------    2 drichard drichard       4096 May 29 15:56 mozilla-media-cache

Out of the box, Firefox does not support multi-users with this cache.  The 'fix' is to do this in the script:

mkdir /tmp/$USER.mozilla 2> /dev/null
export TMPDIR=/tmp/$USER.mozilla

and this gives everyone their own private temporary folder and everything works now as expected.

I'm still working on the new thin client upgrade, and my area of focus right now is making the USB experience better for our users.  We have a situation where some users have full access to the USB sticks, but for many others we just want to give them upload capability only for pictures they have taken with cameras; there is no reason for them to be moving files off the server.   If I open the photo manager automatically, that forces people with full USB access to have another unwanted UI.  So now when users insert a USB device they are given a dialog which describes the two paths they can take and lets them pick (below).

Remember too that the files and USB stick are running locally on the thin client.  The GNOME desktop is not aware of the insert; so there are some nuances in that regard.  As the user performs the various functions, the files are moved to the server via the clipboard (copy/paste) or via FTP file transfer and Nautilus.

So the next improvement area is when to do a sync to the stick.  Those users using the photo manger and clipboard won't need it, but those using drop and drag will.  So I wrote quick little tray/notification applet that when activated does a sync and flushes the files.  When they pick "Full File Manager" they are given a dialog which indicates that the applet is going into the panel.

Nautilus does a great job of hiding the complexities of FTP; and generates nice thumbnails.  When they are finished they right-mouse on the applet and select "Save All Files And Prepare For Eject" and a sync is done.

One of the beautiful things about X/GTK and Linux is the transparency of where the software is running.  GNOME and avant-window-navigator are on the server in our computer room.  The USB notification applet is running on the thin client itself and it properly detects that it should sit into the panel.  If one of our users is performing this USB interaction and running Evolution, LibreOffice and Firefox they very well could be running software from 3 or 4 unique servers along with software running on their workstation and it's completely integrated together.   Next up will be improvements to the simple photo manager and clipboard application for those users that do not have full USB access rights.  This is building on the feedback of those that used the last iteration.

Other Projects: Trying to get some NX issues worked out, installing patches and testing.  LibreOffice 3.5.4 is out, will install that tonight from home and it contains 2 patches that affect us -- very nice to see how fast this software is advancing.


Anonymous said...

I am curious about the Libreoffice bugs you mention - are you able to share any further information?

Dave Richards said...

@anonymous: The two issues that affected us so far

1) Fake XLS files that are really HTML. Lots of download sites and software use this technique to fool MS Office into opening with Excel. The files were opening as a CSV/TXT (regression) and was fixed in the last update.

2) We have some RTF files generated by internal software and they are opening black background with black letters. I entered a bug report and it was replicated. Hopefully it will fixed in the next patch level.