Security-001

feng . Neumann theory

• The computer is binary
• The computer executes in sequence
• Computers include arithmetic units 、 controller 、 Memory 、 input device 、 Five components of output equipment

Kernel state and user state

• Kernel mode ： operating system , Can operate computer hardware
• User mode ： Applications , Do not operate computer hardware

Unix Philosophical thought

• Everything is a document
• small 、 Single purpose
• Link program , Work together
• Avoid confusing interfaces
• The configuration data is stored in a file

Noun

PAE：PAE Technology can make 32 Bit system supports more memory
U： Cabinet height unit ,1u=4.5 centimeter

bc The calculator uses

obase=10（ The base of the output digit ）
ibase=2（ Enter the base of the number ）

Log in and copy

[19:14:31 [email protected][ ~]#echo "ibase=2; 110"|bc
6
[19:14:37 [email protected][ ~]#echo "obase=2; 6"|bc
110

     

      
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