Thursday, January 31, 2013

802.11ac standard


802.11ac: A Survival Guide (PDF)
Wi-Fi Above 1 Gbps

By Matthew Gast


Publisher: O'Reilly Media
Released: August 2013
Pages: 129





The 5G chips use the in-development 802.11ac standard.

Broadcom

  • BCM4360 supports the PCIe interface and implements 3-stream 802.11ac specifications, and reaches speeds up to 1.3 Gbps.
  • BCM4352 and BCM43526 implement 2-stream 802.11ac specification to reach up to 867 Mbps. BCM4352 supports PCIe interface; BCM43526 supports the USB interface.
  • BCM43516 supports USB and reaches speeds of up to 433 Mbps with its single stream 802.11ac implementation.

All four models use the 80 MHz channel and a technology called beamforming, which uses specific receivers to increase the operational range.

Atheros



Reference:
http://www.wikidevi.com/wiki/List_of_802.11ac_Hardware

Tuesday, January 22, 2013

802.11n standard



802.11n: A Survival Guide (PDF)
Wi-Fi Above 100 Mbps


By Matthew Gast

Publisher: O'Reilly Media
Released: April 2012
Pages: 146




IEEE Standard
IEEE 802.11n-2009—Amendment 5: Enhancements for Higher Throughput. (PDF)

Reference:
1. IEEE 802.11 working group
2. 802.11ac: http://scottshulinux.blogspot.tw/2013/01/80211ac-standard.html

Friday, January 11, 2013

HOWTO: recover deleted files from an ext3 or ext4 partition

extundelete

extundelete is a utility that can recover deleted files from an ext3 or ext4 partition. extundelete uses information stored in the partition's journal to attempt to recover a file that has been deleted from the partition.

But, there is no guarantee that the deleted file will be able to be undeleted!

For example:
[ ]# extundelete /dev/sdc1 --restore-all

extundelete will restore any files it finds to a subdirectory of the current directory named “RECOVERED_FILES”.

Wednesday, January 2, 2013

Freescale iMX6


Description: i.MX6Q SABRE LITE BOARD
Silicon Manufacturer:Freescale
Core Architecture:ARM
Core Sub-Architecture:Cortex - A9
Silicon Core Number:i.MX6
Silicon Family Name:i.MX6 Quad