Linux & Systems on punt2cpu

Big and Little Endian

Mon, 28 Aug 2017 10:45:11 +0000

Big endian - most significant byte stored in smallest address, read from left to right.

Let’s take a 32-bit value :

0x09080706 :

09|08|07|06

byte address : x|x+1|x+2|x+3
For example 32-bit value 5 writing as 0x00000005 is a Big endian.

Little endian - least significant byte is stored in smallest address, read from right to left.

32-bit value would be stored in memory in following way :

0x09080706 :

06|07|08|09

byte address : x|x+1|x+2|x+3
For example little endian value would be 16-bit value **53 **in 0x3500

Small how to setup a WiFI device on your FreeBSD machine.

Thu, 24 Aug 2017 11:41:05 +0000

Scanning for wifi networks :
ifconfig wlan0 up scan

Setting up your wifi device :Network-Wireless

This example shows the Atheros ath0 wireless adapter.Add an entry for this network to /etc/wpa_supplicant.conf. If the file does not exist, create it. Replace myssidand mypsk with the SSID and PSK provided by the network administrator.

network={

ssid=“myssid” psk=“mypsk”

}

Add entries to /etc/rc.conf to configure the network on startup:

wlans_ath0=“wlan0”
ifconfig_wlan0=“WPA SYNCDHCP”

Restart the computer, or restart the network service to connect to the network:
# service netif restart
After 8.0v, it is necessary to create a wlan clone device of the actual wifi card :
# ifconfig wlan0 create wlandev ath0
# ifconfig wlan0 up list scan

Apt-get/Yum through proxy

Thu, 24 Aug 2017 11:28:31 +0000

**APT-GET **

In case if your access is going through proxy server you need to provide the credentials to APT.

Just create an apt.conf file in /etc/apt/ and add there the following entry :

Acquire::http::Proxy “http://proxyadd:port”;

In case if authentication is needed :

Acquire::http::Proxy “http://username:password@proxyadd:port”;

**YUM **

/etc/yum.conf

proxy=http://proxyadd:port
proxy_username=user
proxy_password=passwd