Google Gears users can now read and browse our blog even while not connected to network. The Gears is an extension to Browser that stores the contents of website locally on a machine where the browser is used. Then even the network connection is lost, the browser can access the parts of the page from locally stored copy (architecture) and the user is able to use the website as usual.

To enable offline access we used wp-offline plug-in with WordPress. The setup procedure was very easy and straightforward. However, as the Gears uses same origin security policy, we had to do small reconfigurations to our website. We mapped everything under delaytolerant.com to appear under domain www.delaytolerant.com. The mapping was easily done by manipulating .htaccess file according to good instructions for web redirecting.

This far, it is only possible to read the blog but we are looking forward to future where the users are able to also write posts while not online, and synchronize them after they become connected. If you have Gears installed, you should see a link to start with just above the search box on the right-hand side.

UPDATE: With new OS (with skype and everything!) the slow ssh server functionality has disappeared.

Some time ago we installed an ssh server on Nokia N800. It was quite a surprise how long tie it took to establish an ssh session from laptop to N800. Some google searches revealed that the problem lies in the power-save properties of the device. When not used for some time the wireless goes into power-save mode and it takes some time to get the network up and running. The issue does not really exists when you are browsing the net with the gadget since the network interface is kept in ready state when user input is given. However, if no user input is given and the network goes into sleep, the server applications are not terribly rapid on responding on the connections. In the following we measure response time by looking on how the N800 responds to pings.

The figure shows how the first ping is always slower than the consecutive ones. We started series of 10 pings (each with one second intervall) after one minute was elapsed from last series. This results in from network interfaces power-save properties. Once the network is woken and under constant communication the working is much faster. We plotted the average of ten runs with the standard deviation which shows that in addition to slowness the response for one ping is more un-predictable.

Well, this gives just a small example on one device. Still, it illustrates nicely how the mobile devices have their own particularities which should be taken into account when applications are developed.

Google has released a beta version of Google Gears which is a toolkit for developing offline applications. The client part of Gears is a web browser plug-in which installs with simple single click install (so simple that is definitely worth trying). Then user is able to store web sites locally for later offline access. One could e.g. store travel information to a laptop and then later while on the road access the site without network connection.

The Google Gears architecture uses local data storage to store the website data locally on the machine which runs web browser. When the network connection cannot be used to access the server, the Gears may provide the web resource from local data base in the user’s own machine.

Dojo Offline Toolkit is an extension on top of Google Gears that advertises to make the using of the Gears more easier, worth checking out.

UPDATE: We followed (maemo instructions) which are given for older PPC based Macs, the OSX flasher worked perfectly well also with new Intel based MacBook. After all, it’s the version of the firmware that counts in the end, not the version of of the flasher itself.

Here we also explain how we succesfully managed to flash the N800 firmware by using the freely available beta version of VMware Fusion. The installation process of VMware on Intel based MacBook was a straightforward procedure. Then one can use his favorite Linux distribution as a VM guest operating system, we used the Ubuntu 7.04 distribution, which worked nicely (except for minor difficulties in mounting the USB but booting the guest OS with USB attached helped). The advantage on working with distribution which used .deb packages is that the same packet manager is used in N800 and one has to learn the tricks only for one packet management system.

The procedure of installing a Linux distribution causes perhaps a bit more overhead than necessary, but one also gets a nice introduction to virtualization for free. The beta version of WMware Fusion downloads for free without registering and the quality product was a pleasure to use. The virtualization approach helps to use also other Linux based development tools on Mac.

OpenC is a set of POSIX libraries for s60 on Symbian. These libraries can be used by developers to easily start writing software on s60 platform without steep learning curve.