Data Representation 大学计算机基础教学资源库
Data Representation
Basic concepts A bit is the most basic unit of information in a computer. ·It is a state of“on”or“off,in a digital circuit. Sometimes they represent high or low voltage A byte is a group of eight bits..It is the smallest possible addressable unit of computer storage. 大学计算机基础教学资源库
Basic concepts 2 A bit is the most basic unit of information in a computer. • It is a state of “on” or “off” in a digital circuit. • Sometimes they represent high or low voltage A byte is a group of eight bits.. It is the smallest possible addressable unit of computer storage
A word is a contiguous group of bytes. Words can be any number of bits or bytes. Word sizes of 16,32,or 64 bits are most common. 大学计算机基础教学资源库
3 ⚫ A word is a contiguous group of bytes. ⚫ Words can be any number of bits or bytes. ⚫ Word sizes of 16, 32, or 64 bits are most common
1KB(Kilobyte)=1024B 1MB(Megabyte)=1024KB, 1GB(Gigabyte)=1024MB, 1TB(Trillionbyte)=1024GB,1024=2^10 大学计算机基础教学资源库
• 1KB(Kilobyte)=1024B • 1MB (Megabyte)=1024KB， • 1GB (Gigabyte)=1024MB， • 1TB(Trillionbyte)=1024GB，1024=2^10
Number Systems Base or Radix r system uses distinct symbols for r digits Most common number system Decimal, Binary,Octal,Hexadecimal Positional-value(weight)System r2 r 1r.r1 r2r3 -Multiply each digit by an integer power of r and then form he sum of all weighted digits 大学计算机基础教学资源库
Number Systems • Base or Radix r system : uses distinct symbols for r digits • Most common number system :Decimal, Binary, Octal, Hexadecimal • Positional-value(weight) System : r 2 r 1 r 0 .r-1 r -2 r -3 – Multiply each digit by an integer power of r and then form he sum of all weighted digits 5