Hexadecimal, Binary and Denary number system

Binary data is two-state, 0 or 1, on or off.
1 bit = 1 binary digit of data
4 bits = a nibble
8 bits = byte
Kilobyte (Kb)
This is 1024 bytes
It is npt 100 bytes because computers work with binary numbers, so it is 2 to the power of 10 to be 1024 and the closest to 1000.
How many bits in a Kilobyte
1024*8 8192
Units start on the right like this : 128|64|32|16|8|4|2|1
132 = 10000100
96 = 01100000
10 = 00001010
254 = 11110100
67 = 01000011
102 = 01100110
59 = 00111011

00101010 = 42
00101111 = 47
01111110 = 126
11111111 = 255
11011101 = 221
11001000 = 200
10111011 = 187
10101001 = 169
BINARY ADDITION
8 4 2 1
-------
1 0 1 0
0 0 1 0 CARRY THE ONE
-------
1 1 0 0

5 + 6
-------
0 1 0 1
0 1 1 0 CARRY THE ONE
-------
1 0 1 1
-------
11

10 + 4
------
1 0 1 0
0 1 0 0 CARRY THE ONE
-------
1 1 1 0
-------
14

2 + 3
-----
0 0 1 0
0 0 1 1 CARRY THE ONE
-------
0 1 0 1
-------
5

12 + 1
-------
1 1 0 0
0 0 0 1 CARRY THE ONE
--------
1 1 0 1
-------
13

14 + 2
-------
1 1 1 0
0 0 1 0 CARRY THE OVERFLOW
-------
OVER FLOW

8 BIT ADDITION
128 64 32 16 8 4 2 1
--------------------
10000000
00100000
--------------------
10100000
160

00111110
00110010 CARRY THE ONE
--------
01110000
112

01100010
00000100
--------
01100110
102

00010101
10101000
--------
10111101
189

11110000
10000010
--------
OVERFLOW

Hex
Programmers often write numbers down in hexadecimal form. Hexadecimal numbers are based on the number 16, they have 16 different digits:
0,1,2,3,4,5,6,7,8,9,A,B,C,D,E,F

BINARY TO HEX
01101010 = 6A
It makes it a lot easier if you break it up into 2 4 digit numbers rather than 1 8 digit number, for example:
01101010
[0110][1010]
11111110 = FE
00100000 = 20
00100010 = 22

HEX TO DENARY
A1 = 10*16 + 1 = 161
DF = 223
79 = 121
33 = 51
C4 = 196
7B = 123

How many Kilobytes in a megabyte?
1024
How many Kilobytes in a gigabyte?
1048576
How many megabytes in 4 terabytes?
4194304 Mb
How many bits in a petabyte?
1.1102230246252E-16
How many bits in a Yottabyte?
1.0339757656913E-25 No jokes here.
Tell me what base 10, Base 2 and base 16 are
base 10 is the denary number system
base 2 is the binary number system
base 16 is the hexadecimal number system
Tell me where hexadicmal is used and why?


Keywords

A Video about keywords

A few of the many keywords that are used in coding/programming.

Networks

LAN (Local Area Network)

LAN or Local Area Network is most commonly used as Ethernet LAN, Ethernet LAN is used with two or more Nodes (Nodes are devices connected to the network), LAN commonly used for things like: Sharing Files,  Multiplayer Video Games or other tasks.

Advantages

• They are often faster than wireless network connections
• Anyone who wants a file can join the network and access it.

 Disadvantages

• Anyone who can access the network can access everyone who is on the network
• Networks are difficult to maintain and require specialised technicians.
• The ability to expand the network is difficult compared to a wireless networks and Either cables have to be strung underfoot, or walls and floors ripped out and jacks added in to allow users to connect to the network.
  

  DNS servers

  Advantages of a DNS Server:

  An advantage of using DNS to redirect clients is that it is a natural way of informing the clients about the service addresses. It is used by many existing network services, and is very likely to be used by those to come as well.
  Moreover, DNS is supported by a huge infrastructure of millions of DNS servers, capable of caching the answers our redirector generates. Once we make this infrastructure work for us, both efficiency and availability of our redirector considerably increase. 
  One more important advantage of DNS is that it allows multiple replica addresses to be returned, enabling the client to choose one from them.
  Disadvantages of a DNS Server:

  On the other hand, using DNS-based redirection leads to a few difficulties. The first of them is caused by the fact that DNS queries carry no information about the client that triggered the name resolution.
  All that the service-side DNS server knows is the network address of the DNS server that asks about the service location.
  Therefore, we have to assume that clients always use a DNS server that is close to them, and approximate a client's location to that of its DNS server. Whether we consider it to be a drawback or not depends on the accuracy we want to achieve.

  Studies show that 64% of clients are located in the same network as their DNS servers. Thus, as long as we do not need strict per-client redirection, the location of the client DNS server approximates the client well enough.

  How a DNS server accesses a website

  DNS is a protocol within the set of standards for how computers exchange data on the Internet and on many private networks, known as the TCP/IP protocol suite. Its basic job is to turn a user-friendly domain name like "Google.com" into a IP address like 70.42.251.42 that computers use to identify each other on the network.

Hardware

NIC

An NIC or network interface controller, is a component of hardware that connects a computer to a computer network

Hub

A hub or network hub is used to connect multi Ethernet devices making them act as a single network segment.

Router

A Router is a device that forwards Data Packs between computer networks, creating an overlay internetwork.

Switch

A Network hub is a computer networking device that is used to connect devices together on a computer network by performing form of packet switching.

Servers

There are many requests that the server can provide for the client such as: The server component provides a function or service to one or many clients, which initiate requests for such services. For example, a web server serves web pages and a file server serves computer files. A shared resource may be any of the server computer's software and electronic components, from programs and data to processors and storage devices.

What is the Internet?

 The Internet is a massive public spiderweb of connections from different devices. It connects personal computers, mainframes, cell phones, GPS units, music players etc. All of these computer connections exist for the sake of free information sharing. All these devices together create the network of networks. The Internet is a system that changes in little ways as elements join and leave networks around the world. Some of those elements may stay fairly static and make up the backbone of the Internet.

What is WWW?

The World Wide Web is a network of computers that serve webpages. The World Wide Web is a major component of the Internet, along with email, ftp, and some other minor protocols. Documents on the World Wide Web are traditionally written in HTML, a major component of the web. HTML defines the appearance and content of what the website wants to be.

TCP/IP

TCP/IP (Transmission Control Protocol/Internet Protocol) is the basic communication language or protocol of the Internet. It can also be used as a communications protocol in a private network .When you are set up with direct access to the Internet, your computer is provided with a copy of the TCP/IP program just as every other computer that you may send messages to or get information from also has a copy of TCP/IP.

 Network Topology

There are three main Network Topology's and they are:

Bus Network

A Bus Network is a network of computers which has one common linking cable and nodes that are connected of the cable, another reason why this is often used is because it is cheap and easy to setup. Although it is easy to setup and cheap it doesn't work to well if you have high activity between devices as this would cause a lot of data collisions.

Star Network

A Star Network is a network of devices with a central hub system acting as a go between for all of the devices on the network, the advantages of the network work would be that it wouldn't cause many data collisions and would be a fast, reliable network. The main disadvantage and it is a big disadvantage is that if the central hub were to go down that would cause the network to be inoperable and the Network wouldn't be able to function while the central hub was down. Another disadvantage would be that all information travels through the main central hub so if the central hub was compromised that would mean that the whole networks information would be available.

Ring Network

A network topology that is set up in a circular fashion in which data travels around the ring in one direction and each device on the ring acts as a repeater to keep the signal strong as it travels. Each device incorporates a receiver for the incoming signal and a transmitter to send the data on to the next device in the ring. The network is dependent on the ability of the signal to travel around the ring. When a device sends data, it must travel through each device on the ring until it reaches its destination.



 

System Software

The 3 different types of software:

• System Software:

• Operating System
• Device Drivers
• Maintenance

• Developing Software

• Programming Languages
• Utilities

Developing software use Compilers, Compilers translate the high-level code used by the programmer into machine instructions required by the computer. They also use Interpreters, interpreters also translate high-level code but they translate it and execute it one instruction line at a time instead of translating the whole code. Assemblers are also used to translate assembly language but they translate it into Mnemonics instead of binary code, Mnemonics are a type of aid to help a person understand something. Linkers are used to connect sub programs using different language or tools the linker combines all these bits of code to make them work together. Developing software can also use a number of languages such as: C#, JavaScript, HTML, Python etc.

• Applications

• Steam
• Google Chrome

Multi-Tasking

A Multi-tasking operating System allows several processes at once to be in the RAM at the same.

• Running: The CPU is currently dealing with process and others must wait
• Runnable: The current programs are ready to go and are waiting for the to be completed
• Waiting: These programs are waiting to get into the Queue to become runnable

 

 Operating Systems:

Windows: Windows is the most well known operating system for computers and has be used since 1983

 

MacOS: The second most known Operating software is only available for Apple Computers since

1984 and is run on closed source software

 



Unix: Unix is not known about well and uses a command line interface.







 

 

 Security and Maintenance

 Security and Maintenance is used on all computers using things like backups, Defraggers and Anti-Virus used to protect the used information and protect from unwanted software or software that will slow down your computer. What Defraggers do is when you have some unorganised files and what a disk defragger does is sort them out and stores them. Disk Cleaners are also used to get rid of unused files or software that hasn't been used. Backup software makes a complete copy of selected data onto a second hard drive or external hard drive. 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 



Devolpment Software

Development Software

 Editors

To write any programs, you need an Editor. Text Editors are usually provided by the operating system; for example Windows provides notepad and Linux provides Gedit. Although you can use any text editor to write a program you can get some advanced and added features for a programs like "Pretty Printing".

 

Compilers

Compilers turn High-level languages like Python into Machine Instructions so it is easier for the CPU to execute. They do not often come supplied with an operating system, but they are still regarded by some as system software because they are not applications designed to do a specific task for the user.

 

Interpreters

Interpreters also translate High-Level code into machine code ,but they do so a line at a time and execute the code as they go. They are useful for debugging programs because they give an instant result.

Bits and Bytes

The following will go up in order of File Sizes from Bit to Terabyte.
A bit is the basic unit of information in computing and digital communications. A bit can have only one of two values, and may therefore be physically implemented with a two-state device. The most common representation of these values are 0and1 or off and on. The term bit is a contraction of binary digit.
A Nibble (often nybble or even nyble to match the vowels of byte) is a four-bit aggregation,or half an octet. As a nibble contains 4 bits, there are sixteen  possible values, so a nibble corresponds to a single hexadecimal digit.
A byte is a unit of digital information in computing and telecommunications that most commonly consists of eight bits. Historically, the byte was the number of bits used to encode a single character of text in a computer and for this reason it is the smallest addressable unit of memory in many computer architectures. The size of the byte has historically been hardware dependent and no definitive standards existed that mandated the size. The de facto standard of eight bits is a convenient power of two permitting the values 0 through 255 for one byte. The popularity of major commercial computing architectures has aided in the ubiquitous acceptance of the 8-bit size.
The kilobyte for 1000 bytes (symbol: kB) or Kilobyte (kibibyte) for 1024 bytes (symbol: KB or KiB or informally KBytes) are two definitions for multiples of the unit byte for digital information. The term kilobyte and the symbol KB have historically been used to refer to 1024 (2¹⁰) bytes, in the fields of computer science and information technology.
The megabyte (symbol MB, sometimes abbreviated as Mbyte) is a multiple of the unit byte for digital information storage or transmission with three different values depending on context: 1000000 bytes (10⁶, see prefix mega-) generally for computer storage or transmission rates;^[ 1048576 bytes (2²⁰, or a mebibyte) generally for computer memory; and in rare cases 1000×1024 (1024000) bytes.
The term "gigabyte" is commonly used to mean either 1000³ bytes or 1024³ bytes. This originated as compromise technical jargon for the byte multiples that needed to be expressed by the powers of 2 but lacked a convenient name. As 1024 (2¹⁰) approximates 1000 (10³), roughly corresponding SI multiples, it was used for binary multiples as well. In 1998 the International Electrotechnical Commission (IEC) proposed standards for binary prefixes and requiring the use of gigabyte to strictly denote 1000³ bytes and gibibyte to denote 1024³ bytes. By the end of 2007, the IEC Standard had been adopted by the IEEE, EU, and NIST.
 The terabyte is a multiple of the unit byte for digital information. The prefix tera represents the fourth power of 1000, and means 10¹² in the International System of Units (SI), and therefore one terabyte is one trillion (short scale) bytes. The unit symbol for the terabyte is TB.
1 TB = 1000000000000bytes = 10¹²bytes = 1000gigabytes. A related unit, the tebibyte (TiB), using a binary prefix, is the corresponding 4th power of 1024. One terabyte expressed using binary prefixes is about 0.910 tebibytes, or 931 gibibytes.

Programs Instructions

Programs instructions and data are stored by the computer in binary in the same place. When a Computer starts a program it directs itself to the start address for the instructions. The CPU fetches the instructions from the program location and Decodes it to find out what the next instruction is. In the meantime it has already updated a Register, the Program counter, to point at the next memory location so that it is ready to fetch the next instruction if necessary.
Operand may be literals, such as the number "3," or strings, such as "Hello." Or they may be variable names such as "x" or "speed".
Operator represent actions that can be performed on the operands. The most obvious operators are the symbols for the four common arithmetical operations: "+," "-," "*" (multiplication), and "/" (division). However, most computer languages also define other operators.

The Video below will help explain.