Jun 20, 2012

Caboooo! Cabooooo! Acabooooo!



Assim que fiquei sabendo a última nota que faltava, me lembrei do Galvão bueno comemorando alucinadamente a final da copa de 1994.

Finalmente me formei!

Caboooo! Caboooo! Acabooo!

Jun 9, 2012

Enable power button on minimal install of Fedora 17

After fresh Fedora 17 minimal install, pressing the physical power button has no effect. This is valid for both virtual machines and physical servers. To fix it, just:

# yum install acpid
# reboot

Jun 3, 2012

Communication between two MSP430

I like the LauchPad kit due its price under USD 5. But I also like it due its simplicity.

The Lauchpad kit includes two MSP-430 chips. It is very easy to make the second chip to work with just a few components.

Schematic used for the second MSP430

This schematic is from: http://www.msp430launchpad.com/2010/07/schematic-images-and-explanation.html

I made two simple programs that communicate with each other. The source code is at:
https://github.com/petersenna/msp430/blob/master/rx-device.c
https://github.com/petersenna/msp430/blob/master/tx-device.c


Lightning fast boot with Fedora17

See Harald Hoyer article: Fedora 17 Boot Optimization (from 15 to 2.5 seconds).

One of the boot steps that consumes about 3 seconds is the decompression and running of initrd. If you do not use LVM, software RAID or partition encryption you may not need initrd.

But Grub2 is configured to always use initrd for booting. If you modify by hand the file /etc/grub2.cfg, it will last until your next Kernel update. To avoid this, I made a grub configuration file that will generate entries without initrd even for new Kernels. Check it out at:

https://github.com/petersenna/Fedora17-fastboot


[peter@ace Fedora17-fastboot]$ systemd-analyze
Startup finished in 1433ms (kernel) + 2150ms (userspace) = 3584ms

3.5 seconds is good for me and I still have a fully operational Fedora 17. :-D