Computer Basics

Introduction to computer basics

• Computer processing is designed around binary  and we should have some familiarity with binary if we will be working computers.

• The process for the conversion of decimal  numbers to binary  and hexadecimal  is a straightforward and practical.

Key Topics

Electrical pulses One’s and zero’s Size Definition Reasons for Conversion

Working in base 10 Working in base 2 Converting to Binary Converting to Hexadecimal ASCII

Electrical Pulses

• Since computers use electrical pulses to communicate then a pulse = yes = 1 and no pulse =No = 0.

• Therefore computers work by using ones and zeros which is in reality using the binary  numbering system.

Ones and Zeros

• Each one or zero defines a bit of data.

• 8 bits of data is equivalent to one byte of data.

• 10101101 = 1byte of data.

• Information  is usually defined in bytes.

Size definitions

• The quantities of space within the different devices  such as the hard drive  or the memory  are measured in proportions of bytes.

• 8 bits = 1 byte

• 1024 bytes = 1KB (Kilobyte)

• 1024 KB = 1MB (Megabyte)

• 1024 MG = 1GB (Gigabyte)

• 1024 GB  = 1 TB (Terabyte)

• 1024 TB = 1 EB (Exobytes)

Reasons For Conversions

• Although binary  defines how computers work, humans work in decimal  and find it difficult to understand binary.

• Hexadecimal numbers are used because

• When we deal with numbers larger then 8 bits in modern computers that are 32/64 bits it becomes difficult to keep a tab on all the ones and zero’s for human beings.

• They provide an easy conversion route to binary

Reasons For Conversions

• You will need to be able convert  decimal  numbers into binary  and hexadecimal  and vise versa as part of your job.

• The situations where conversion is useful include: -

• Defining the IRQ , DMA  and IO address .

• When dealing with TCP /IP  addresses 

• When dealing with jumper  setting and SCSI

Working In Base 10

• We are familiar with base 10

• Within base 10 the largest single digit number we can have is 9

• To calculate the value of a number

 

 

 

 

 

 

 

 

	Is equivalent to: - (5x1000)+(3x100)+(2x10)+(1x8) = 5328

 

Working with base 2

• Within base 2 the largest single digit number is 1

• To calculate the decimal  value of a binary  number we look at the example below

10011000 is equivalent to: - (1x128) +(0x64) +(0x32)+(1x16)

                                    +(1x8)+(0x4)+(0x2)+(0x1)

                        = 128+16+8=152 in decimal

 

Converting to Binary Example1

• When converting a decimal  number to binary ,

 

 

 

 

Converting to Binary Example 2

• When converting a decimal  number to binary ,