Uses of hexadecimal numbers in computing

1.1.2 Representation of numbers stored in registers and main memory as hexadecimal Hexadecimal is used as an intermediate step between binary and denary because it is easier for a computer to convert between binary and hexadecimal than between binary and denary whilst at the same time being easier for a Human to process than a binary number would be.

It is also used because a single hexadecimal numeral can store 1 nibble (4 binary digits) and we can store a whole byte using only 2 hexadecimal numerals. Depending on the application this can have benefits in both storage space and processing time.

Uses of Hexadecimal Numbers in Computing 1. Use of hexadecimal in Memory Dump 

A memory dump can be considered as a process in which the contents of memory are displayed and stored,

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in case of an application or system crash.

Memory dump is also known as core dump and Blue Screen of error / Death (BSoD).

Memory dump is a common problem mainly come across in various versions of windows operating system.

A blue Screen memory dump is an error screen that comes up just before the system gets rebooted, because the operating system is no longer able to function properly due to a variety of reasons and the content of the RAM is dumped on to a data file.

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Memory dump helps software developers and system administrators to diagnose / identify and resolve the problem that lead to application or system failure. They are used primarily for debugging purpose since

they allow software developers and system administrators to see exactly what is contained at each memory   

location in the dump.

There are few ways to format a memory dump.

Hexadecimal number system is used as shortcut notation for memory dump by computers.

Computer memory is inherently binary, but by using hexadecimal, it is no longer necessary to look at a long

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sequence of 0’s and 1’s.

4 bits are grouped together in a nibble and that nibble is printed out as a hexadecimal digit.

Use of Hexadecimal in HTML 

Hypertext Markup Language (HTML) is used to write content on webpages. HTML is not a programming

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language, it is referred to as markup language.

HTML uses tags inorder to write commands in the language. There is always a starting and ending tag,

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which will be used to display contents on the webpage.

All of the tag names are enclosed with opening and closing angle brackets. e.g. <tag> contents </tag> <b> contents</b>

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HTML code makes use of hexadecimal when representing colours on the screen. The colour is specified according to the intensity of it’s Red, Green and Blue (RGB) components, each represented by 8 bits.

Therefore, there are 24 bits used to specify a Web color.

HTML TAGS representing colors Names RED <font color="#FF0000"> RED </font> <font color="#00FF00"> GREEN (LIME) GREEN</font> <font color="#0000FF"> BLUE </font> BLUE <font color="#FFFF00"> YELLOW YELLOW </font> <font color="#FF00FF">

MAGENTA MAGENTA (FUCHSIA)

</font> <font color="#00FFFF"> CYAN </font>  

CYAN (AQUA)

RGB color values are supported in all browsers.

Each parameter (RGB) define the intensity of the color as an integer between 0 and 255. (256 colors / shades)

COLOR

RGB

COLOR

RGB(255,0,0)

Red

RGB(0,255,0)

Green

RGB(0,0,255)

Blue

HTML color codes are given in hexadecimal values rather than decimal values as…

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this uses fewer characters which therefore makes the file smaller, which in turn would allow the page to load faster over a slow network connection.

Use of Hexadecimal in MAC address 

MAC (Media Access Control) address is a unit number associated with network interface cards which

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identify a particular machine/ device.

This allows all devices to uniquely identify themselves on a computer network. eg. Internet A MAC address is 48 bits long, therefore MAC address can be assigned to 281 billion computers.

The MAC address is commonly written as a sequence of 12 hexadecimal digits as follows.

Format of a MAC address: MM – MM – MM – SS – SS – SS OR

mm : mm : mm : ss : ss : ss 

The first 6 hexadecimal digits represents the identification number of the manufacturer of the digits and the second 6 hexadecimal digits represent the serial number of the device.

e.g. :

00 – A0 – C9 – 25 – F4 – 3D Represents a device manufactured by INTEL with a serial number of 25F43D.

Use of Hexadecimal in Web Addresses   

Web browsers request pages from web servers by using “URL” (Uniform Resource Locator).

The URL is the address of a web page like: www.britishschool.lk URL’s can only be sent over the internet using the ASCII characters set. (American Standard Code for

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Information Interchange) Since URL’s often contain characters outside the ASCII set, the URL has to be converted into a ASCII format.

URL encoding replaces unsafe ASCII characters with a percentage sign ‘%’ followed by 2 hexadecimal digits.

URL encoding cannot contain spaces. URL encoding normally replaces a space with a plus (+) or (%20) e.g. Represent

www.hodder.co.uk

by using hexadecimal values.

The percentage sign (%) is used to denote that hexadecimal is being used.

ASCII (American Standard Code for Information Interchange) Conversion Table (Decimal – Binary – Hexadecimal)

Complete Activity 1.9 using the ASCII code table.

Assembly Language and Machine Code  

Memory locations can be addressed directly using assembly language or machine code.

In low- level languages such as machine code or assembly language programming, to address low level components we are using addresses with hexadecimal values.

e.g.

ADD

A7F4

ADD

1010011111110100

 Compared to binary use of hexadecimal makes it much easier, faster and less error prone to write codes.

Debugging    

Debugging allows programmers to detect, diagnose and eliminate errors in a program.

The source debugger uses the hexadecimal values of the characters.

Hexadecimal often used in error messages.

Hexadecimal number refers to the memory location of the error. This helps programmers to find and then fix problems.