## Sunday, November 30, 2014

### Binary I

To get into field of any software engineering you must know a few number systems. You guessed it right; one of them is binary!

• Binary is a numeric system which uses two numerals to represent all real numbers.: typically 0 (zero) and 1 (one).
• Binary number systems are usually represented in octets, meaning that there are 8 binary numbers per octet for example: 00000000 or 10101011
• Binary is useful in resolving IP addresses, decoding decimal values and more.

• In the binary numbering system, the radix is 2. Therefore, each position represents increasing powers of 2. In 8-bit binary numbers, the positions represent these quantities:
• 2^7 2^6 2^5 2^4 2^3 2^2 2^1 2^0 = 128 | 64 | 32 | 16 | 8 | 4 | 2 | 1

• A 1 in a certain position means we add that value to the total. A 0 means we do not add that value. For example the binary number 0110000 has a 1 in the 2^6 position (decimal value 64) and a 1 in the 2^5 position (decimal value 32). The remaining bits are all 0 so we do not add the corresponding decimal values. The result of adding 32+64 is 96, the decimal equivalent of 01100000.
• Each octet is made up of 8 bits or 8 binary numbers and each bit has a value, either 0 or 1. The four groups of 8 bits have the same set of valid values in the range of 0 to 255 inclusive.
Overview

• If there is a 0 in a position, do not add the value.
• If all 8 bits are 0s, 00000000, the value of the octet is 0.
• If all 8 bits are 1s, 11111111, the value of the octet is 255 (128+64+32+16+8+4+2+1)
• If the 8 bits are mixed, the values are added together. For example, the octet 00100111 has a value of 39 (32+4+2+1)

## Monday, November 10, 2014

Greetings, it has been a while since my last post, however, I am back!
• Since the last topic which was Deep web, we will go to the genera of networking and Cisco internet work operating system.
• There will be posts about packet tracer tutorials to set the user up for practicing with such interfaces.
• Fortunately there will be a post about CG&P in which is mainly relevant to networking applications.
• Expect posts  starting 2015, cheers!