①X86 refers to the 32-bit system (bit: the maximum number of bits that can be processed once cpu .... so much faster than the 64-bit 32-bit speed)
② memory: CPU read and write operations can be computer components through a bus address, and.
Computer memory (RAM, random sccess memory, random access memory, also called the main memory (RAM)): is the memory bridge of communication with cpu, all programs running on the computer in the memory.
These are some of the relevant knowledge, and now into the question:
Addressing capability (1) 32-bit system (address space: a computer entity represents any occupied memory size)
It is 4GB = (2 ^ 32) B, ranging from 0 to (2 ^ 32) -1
Therefore, the maximum address is (2 ^ 32) -1, can be considered together with the memory, the address to 4GB after addition, after the address can not be represented.
(2) 64-bit system in the range 0 to (2 ^ 64) -1
Want more memory than 4GB, you need to change the 64-bit system.
He added: ①32 bit binary representation is 32 bits (4 bytes).
int type 32bit (4B)
Int 64-bit length type 64bit (8B)
②1kB = 1024B = 2 ^ 10 (power in binary form)
1MB=1024kB =2^20
1GB=1024MB =2^30
1TB=1024GB =2^40
……