Tuesday, November 29, 2016

How one tweet can ruin your life | Jon Ronson

Think before you post anything online. How one tweet can destroy your life.




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Wednesday, November 16, 2016

Babbage's Analytical Engine - Computerphile


Babbage's Analytical Engine



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Tuesday, November 8, 2016

Illegal Numbers - Numberphile


Illegal Numbers - Numberphile



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Wednesday, November 2, 2016

The Josephus Problem - Numberphile


In computer science and mathematics, the Josephus problem (or Josephus permutation) is a theoretical problem related to a certain counting-out game.
People are standing in a circle waiting to be executed. Counting begins at a specified point in the circle and proceeds around the circle in a specified direction. After a specified number of people are skipped, the next person is executed. The procedure is repeated with the remaining people, starting with the next person, going in the same direction and skipping the same number of people, until only one person remains, and is freed.
The problem — given the number of people, starting point, direction, and number to be skipped — is to choose the position in the initial circle to avoid execution.








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The Seven Bridges of Königsberg - Numberphile

The Seven Bridges of Königsberg








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Tuesday, October 25, 2016

Fermat's Little Theorem

Pierre de Fermat  was a French lawyer at the Parlement of ToulouseFrance, and a mathematician who is given credit for early developments that led to infinitesimal calculus, including his technique of adequality.




Khan Academy video explaining Fermat's Little Theorem

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Monday, October 10, 2016

Monday, October 3, 2016

666 - Numberphile

666
Here is wisdom. Let him that hath understanding count the number of the beast: for it is the number of a man; and his number is Six hundred threescore and six. - 
Revelation 13:18 KJV



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Infinity is bigger than you think - Numberphile

Infinity is bigger than you think - Numberphile


Sometimes infinity is even bigger than you think... Dr James Grime explains with a little help from Georg Cantor.

Website: http://www.numberphile.com/




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Professor Messer's Security+ Study Group - September 2016


Professor Messer's Security+ Study Group

September 2016



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Friday, September 30, 2016

Subnetting Made Easier

The below charts will help in subnetting your network. There are a lot  of ways to teach how to subnet. I have my videos here:

Basics of Binary

Subnetting the 4th Octet




Binary to Decimal conversion using addition and subtraction



Subnetting ANDing


Advanced Subnetting




Class address ranges:
  • Class A = 1.0.0.0 to 126.0.0.0
  • Class B = 128.0.0.0 to 191.255.0.0
  • Class C = 192.0.1.0 to 223.255.255.0
Reserved address ranges for private (non-routed) use (see RFC 1918):
  • 10.0.0.0 -> 10.255.255.255
  • 172.16.0.0 -> 172.31.255.255
  • 192.168.0.0 -> 192.168.255.255
Other reserved addresses:
  • 127.0.0.0 is reserved for loopback and IPC on the local host
  • 224.0.0.0 -> 239.255.255.255 is reserved for multicast addresses
Chart notes:
  • Number of Subnets - "( )" Refers to the number of effective subnets, since the use of subnet numbers of all 0s or all 1s is highly frowned upon and RFC non-compliant.
  • Number of Hosts - Refers to the number of effective hosts, excluding the network and broadcast address.

Class A
Network Bits Subnet Mask Number of Subnets Number of Hosts
/8 255.0.0.0 0 16777214
/9 255.128.0.0 2 (0) 8388606
/10 255.192.0.0 4 (2) 4194302
/11 255.224.0.0 8 (6) 2097150
/12 255.240.0.0 16 (14) 1048574
/13 255.248.0.0 32 (30) 524286
/14 255.252.0.0 64 (62) 262142
/15 255.254.0.0 128 (126) 131070
/16 255.255.0.0 256 (254) 65534
/17 255.255.128.0 512 (510) 32766
/18 255.255.192.0 1024 (1022) 16382
/19 255.255.224.0 2048 (2046) 8190
/20 255.255.240.0 4096 (4094) 4094
/21 255.255.248.0 8192 (8190) 2046
/22 255.255.252.0 16384 (16382) 1022
/23 255.255.254.0 32768 (32766) 510
/24 255.255.255.0 65536 (65534) 254
/25 255.255.255.128 131072 (131070) 126
/26 255.255.255.192 262144 (262142) 62
/27 255.255.255.224 524288 (524286) 30
/28 255.255.255.240 1048576 (1048574) 14
/29 255.255.255.248 2097152 (2097150) 6
/30 255.255.255.252 4194304 (4194302) 2



Class B
Network Bits Subnet Mask Number of Subnets Number of Hosts
/16 255.255.0.0 0 65534
/17 255.255.128.0 2 (0) 32766
/18 255.255.192.0 4 (2) 16382
/19 255.255.224.0 8 (6) 8190
/20 255.255.240.0 16 (14) 4094
/21 255.255.248.0 32 (30) 2046
/22 255.255.252.0 64 (62) 1022
/23 255.255.254.0 128 (126) 510
/24 255.255.255.0 256 (254) 254
/25 255.255.255.128 512 (510) 126
/26 255.255.255.192 1024 (1022) 62
/27 255.255.255.224 2048 (2046) 30
/28 255.255.255.240 4096 (4094) 14
/29 255.255.255.248 8192 (8190) 6
/30 255.255.255.252 16384 (16382) 2


Class C
Network Bits Subnet Mask Number of Subnets Number of Hosts
/24 255.255.255.0 0 254
/25 255.255.255.128 2 (0) 126
/26 255.255.255.192 4 (2) 62
/27 255.255.255.224 8 (6) 30
/28 255.255.255.240 16 (14) 14
/29 255.255.255.248 32 (30) 6
/30 255.255.255.252 64 (62) 2


For more information on subnetting, see RFC 1817 and RFC 1812.

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Thursday, September 29, 2016

CompTIA: Let’s Make Tech Her Story


Today, 47% of middle and high school boys have considered pursuing a tech career, compared to 23% of girls. Girls' interest in tech jobs also decreases 30% after they enter high school. Some pin the tech workforce gender divide on the simple fact that women are less interested in technology than men – but we think there’s more to the story.

CompTIA, the voice of the technology industry, launched #MakeTechHerStory: a campaign created to shed light on the real reasons that drive, or detract from, girls’ interest in IT and tech careers. Through commissioned research that brought the conversation directly to girls and boys between the ages of 10 and 17, CompTIA hopes to inspire tech industry leaders, parents, educators and girls themselves to make the industry more inclusive.

Visit www.comptia.org/MakeTechHerStory to learn more about how you can help us #MakeTechHerStory

Facebook - https://www.facebook.com/CompTIA 
Twitter - https://twitter.com/CompTIA 
Instagram - https://www.instagram.com/comptiaphotos








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Wednesday, September 28, 2016

IBM PC - Computerphile

The IBM PC running DOS set a new standard for Personal Computing but IBM lost control, Dr Steve Bagley explains where it started. 



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Monday, September 26, 2016

Elon Musk elaborates on his AI concerns (2016.9.15)

Do you want robot overlords?  Because AI is how you get robot overlords. 








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Satellite Navigation - Computerphile

From Computerphile:  We all rely on sat nav systems, but how do they work? Here to discuss is Steve Fuller of GRACE (Geospatial Research and Applications Centre of Excellence) at Nottingham Geospatial Institute





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