Raspberry Pi 3 disable bluetooth and wifi

To completely disable WiFi and Bluetooth by disabling kernel modules in Raspbian / OSMC add following lines to
/etc/modprobe.d/raspi-blacklist.conf

#wifi
blacklist brcmfmac
blacklist brcmutil
#bt
blacklist btbcm
blacklist hci_uart

Kodi video buffer cache location

When you disable RAM caching by setting “cachemembuffersize = 0” in .kodi/userdata/advancedsettings.xml Kodi will write video cache to disk.
Video cache will be written to kodi temporary folder:

~/.kodi/userdata/temp

with filename:

filecache000.cache

Raspberry pi best heatsink comparison benchmark

raspberry_pi_3_heatsinks

Raspberry Pi manufacturer has stated that you don’t need heatsink for the normal operation of the Raspberry Pi device, however overclocked or heavily stressed devices will benefit from heatsink installation.
I decided to compare available heatsinks on the market and have found the best heatsink for Raspberry Pi 3.

First tested heatsink is small – 14x14x6mm, priced 1$ on Ebay
It has an adhesive layer for mounting on CPU.

raspberry_pi_small_heatsink

Second heatsink – is larger 50x25x10mm, also priced 1$

raspberry_pi_large_heatsink

Mounting was done with Arctic Silver thermal compound and super-glue 🙂 Thermal compound was applied to the center and glue – to the corners of the chip.
Please note that this will be a permanent solution, and you will not be able to remove the heatsink.

For loading the CPU I used stress software (apt-get install stress).
Only 1 core of Raspberry Pi 3 was loaded – frequencies: arm_freq=1290 core_freq=430

Here are the temperature graphs:

raspberry_pi_temperature_heatsink

Red line – no heatsink.
Blue – small heatsink 14х14
Green – large heatsink 50х25

For a price of 1$ you can greatly improve temperature of Raspberry Pi 3 – by 8 degrees in idle state and by 13 degrees under moderate load.

transaction check error – mysql-community-libs-compat conflicts with file from package compat-mysql51

While upgrading MySQL server on centos 6 from 5.5 to 5.7 you may encounter following error:

Transaction Check Error:
  file /usr/lib64/mysql/libmysqlclient.so.16.0.0 from install of mysql-community-libs-compat-5.7.11-1.el6.x86_64 conflicts with file from package compat-mysql51-5.1.54-1.el6.remi.x86_64
  file /usr/lib64/mysql/libmysqlclient_r.so.16.0.0 from install of mysql-community-libs-compat-5.7.11-1.el6.x86_64 conflicts with file from package compat-mysql51-5.1.54-1.el6.remi.x86_64

It can be resolved by running following yum transaction:

$ yum shell
> remove compat-mysql51
> install mysql-community-libs-compat
> run

This will update affected mysql libraries to newer version without breaking any dependencies.