Raspberry pi best heatsink comparison benchmark

raspberry_pi_3_heatsinks

Raspberry Pi manufacturer have stated 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 и 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
Gren – 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.

Remove all store apps windows 10

windows_modern_apps_bloatware

If you don’t use new (modern / metro) style application in windows you can delete all of them with a single PowerShell command.
To open PowerShell: Right click on Windows logo -> Command Prompt (Administrator – type powershell and press Enter.

This command removes all store apps for currently logged in user.

Get-AppxPackage | Remove-AppxPackage

To delete installation packages from disk and prevent installation for new users:
WARNING! This cannot be undone, you will lose ability to install new apps from Windows Store.

Get-AppXProvisionedPackage -Online | Remove-AppxProvisionedPackage -Online

Automating tasks with cron on CheckPoint Gaia

To use cron on CheckPoint Gaia firewall you need to create a separate user, as “admin” user crontab file is overwritten on every reboot by /bin/cron_xlate.

Instead of using default command :
> crontab -e
It will warn you as follows:

#  This file was AUTOMATICALLY GENERATED
#  Generated by /bin/cron_xlate on Wed Jan 14 13:33:33 2015
#
#  DO NOT EDIT
#
SHELL=/bin/bash
MAILTO=""
#
# mins  hrs     daysinm months  daysinw command
#

You will also need to specify the user:

> crontab -u cron_user -e

To create a new user for cron, use following commands:

add user cron_user uid 0 homedir /home/cron_user
set user cron_user  gid 100 shell /bin/bash
add rba user cron_user roles adminRole
set user cron_user password <ENTER>

Make sure you use new user’s home folder for output in your scripts, to avoid issues with permissions.

SSHd server not starting at boot RHEL / CentOS 7

By default sshd server does not start in CentOS 7.
chkconfig command does not control ssh daemon any more.

Solution is to use systemctl:

> systemctl enable sshd

It produces following awkward result:
ln -s ‘/usr/lib/systemd/system/sshd.service’ ‘/etc/systemd/system/multi-user.target.wants/sshd.service’

To check if SSH server is staring on boot (and if it is running):

> systemctl status sshd

sshd.service - OpenSSH server daemon
   Loaded: loaded (/usr/lib/systemd/system/sshd.service; <strong>enabled</strong>)
   Active: active (running) since Mon 2014-11-03 18:43:56 GMT; 20min ago

Enabled – means it will start at boot time automatically.
Welcome to systemd world..