23、 1-bit data storage (delay line / core /dram/sram/ tape / disk / optical disc /flash SSD)

One 、 Storage device principle

Machine instruction set model

1、 register rax,rbx,rcx,...

2、 Physical memory

Requirements for storing the current state

1、 Quick access to

（1） Read and write data according to the number

2、 The access speed is very fast

（1）（ even to the extent that ） Power loss is allowed

（2）memory hierarchy

Two 、 Temporary storage

1、 Core memory

（1） Don't lose power

2、SRAM/DRAM： capacitance

3、 ... and 、 Permanent memory

1、 Magnetic tape

2、 floppy disk

3、 Compact disc

（1） Only read , Can't write

4、 Flash memory （Flash Memory）

（1） Single storage unit , The number of writes is limited

（2） After average algorithm , Average the write data in the entire storage space