Friday, January 06, 2012

DBus Root Cause, iPad Testing

In my last blog I mentioned we were having dbus problems. Right around 96-98 users it would stop allowing additional people into the server and dbus would begin chewing lots of CPU. At first I thought it was hitting a limit and denying additional requests. It turns out that it was hitting a 1024 open file limit, which is clearly seen by going into /proc/process_number/fd and watching the number grow. When it hits 1024 the server goes bad. The ever wonderful Vincent Untz found the git entry in dbus that fixed this issue. These patches had not been merged into OpenSuse 11.4. He is going to generate a new RPM for us. I'll test and we'll try and get it into the update channels. The OpenSuse bug is here.

It's been a disappointment that NX 4 hasn't been far enough along to deploy iPads using NX technology. We have been testing other ideas and only found them to be good enough for IT staff, and they are not ready for consumption by regular users. The various techniques under testing:

VNC: Fast over Wifi; doesn't work over EVDO from iPad; resume not working well; no rotary of ports
RDP: We tested RDP/iPad -- Windows/NX Client -- GNOME/Linux; the hop in the middle produces lag, applications like Xournal are too slow.
Citrix: We are going to test Citrix/iPad - -Windows/NX Client -- GNOME/Linux to see how it works. This is not yet working.
NX4/Safari: The alpha release allows you to connect to GNOME with the Safari browser. It's way too slow on a tablet for regular use. We're hopeful a native client will fix this.

Because of increasing requests for this technology to move in beta testing, we are going to move ahead with an approach that is more "client/server". We will continue working on host based solutions as we move into the new year. Document records retention is paramount in Government, we need solutions that will comply with the law.

The tablet solution as it's shaping up now:

For email we have been looking over Groupwise 2012 and it's wonderful on the tablets. Using just Safari, one gets the UI below. Unlike the older Groupwise version, a single touch of the message list instantly opens the message in a preview pane.

The calendar also is designed well for the real estate of at tablet

Dragon Naturally Speaking works well, and allows you to easily email the text generated by your spoken word:

So being that the NX upgrades are not yet ready, how do we allow people to transfer and read their documents on tablets? There are many middle-ware type applications for this function. But we always have to consider cost and more importantly staff size. At a certain point your infrastructure is so complicated that you almost get to the point that no single can take a day of vacation. We found an application for the iPad that seems elegant in simplicity and are going to begin testing. It's called FileApp. This software is very suited for integration into a GNOME (and even mentions it!) desktop, and supports OpenDocument (OpenOffice/LibreOffice) files. It gives you a very simple interface that shows you all documents you have downloaded from your GNOME desktop, and a single tap of the UI starts an FTP server on the tablet. You are then able to gain access to it the desktop and transfer files. Once the connection is closed, your document list refreshes and you can view them "offline".

From FileApp tap the WiFi symbol and the drop down appears. When this is displaying, FTP is running on the tablet. The UI gives the end users their FTP address which is based on their IP address at the time.

From the GNOME desktop, simply type in the FTP address into Nautilus and it displays all of the documents stored on the tablet:

Once the drop window is removed,FTP closes and your document list refreshes and all available documents appear. You can view them by date or file type.

And further firming up the fact that OpenDocument files are not second class citizens, they open directly on the tablet and won't have to be converted to PDF before their viewing.

This software is moving through our Infrastructure group for testing and then will move to the IT Director. Once that's done, we'll move this to a limit number of testers.

1 comment:

Anonymous said...

Is there a reason you can't just use something like xrdp to do rdp directly to a session running the GNOME/Linux app?

I think xrdp just uses a Xvnc like setup on the server side but you'd still remove a lot of latency without a middle man.