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Computer startup aid using a LEGO train January 6, 2012

Posted by Florian in Devices, kernel concepts.

Some times it happens that I have to dig out some old piece of hardware and try to get it running again… I recently got a very geek present for my birthday – one that requires a working SGI Indigo next to it. Luckily nothing gets lost at kernel concepts and I was able to select from several Indigo gathering dust at the attic of our office. It looks like the machines survived quite some years not being used pretty well – including most of the harddisks. Unluckily all batteries which are supposed to supply the real-time clock chip were flat and these batteries are hard to get and soldered to the board. I did not have a replacement for the 3.6V Lithium battery but it was pretty easy to replace the battery with some cables to supply the board with 3.6V. The first thing to supply 3.6V I found was the electric LEGO locomotive the kids left lying around…

Indigo Lego Train

Indigo Lego Train

This one was powered by three 1.2V AA rechargeable batteries – perfect for some startup aid for this old machine. After applying power I was able to boot into IRIX 6.2 installed on this historic piece of hardware (100MHz MIPS R4000 CPU, 192MB of RAM, 2GB SCSI hard disk, ELAN graphics). I have to admit I somehow enjoyed the “time travel” experience playing around with such an old system for a while. Someone here still remembers the Netscape browser? Or Electropaint? One really scary experience was the network setup: IRIX 6.2 has the ability to configure a static IP through the GUI but obviously you have to edit the network startup script in order to set a default route on boot.

A lot more of information about these machines can be found here.

Android Lessions Part 1: Bluetooth Crash January 4, 2012

Posted by Florian in Android, Source.
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Finally – some free days for family and friends and to write a few lines which might be useful for someone else. Since Android started to become more and more interesting for industrial and business applications I got involved in some projects porting Android to several devices. It turned out that the documentation of the lower layers (hardware and driver adaptation) is very thin in contrast to the SDK and NDK documentation. But I took some notes working on these projects… this one might be useful for other people porting Android 2.3.x and experiencing issues with Bluetooth.

I ran into the issue that activating Bluetooth in the settings application resulted in a crash of the whole GUI. It seems that only ARMv5 core based devices are affected so that only a few people ran into this so far. (Not that it would be correct on more common cores used for Android devices such as ARMv7A, but it does not seem to cause the same effect.) The solution I found in the Android 4 commit log is quite simple for a problem causing that much of hassle:

--- a/core/jni/android_server_BluetoothEventLoop.cpp
+++ b/core/jni/android_server_BluetoothEventLoop.cpp
@@ -311,7 +311,7 @@ static int register_agent(native_data_t *nat,
DBusMessage *msg, *reply;
DBusError err;
- bool oob = TRUE;
+ dbus_bool_t oob = TRUE;