Storage system -------- Jiao Xiao Gang original
In physical composition, storage systems are divided into three levels: cache Cache, main memory, and deposit. Cache is composed of the main storage semiconductor memory. The exemption is often constructed of a disk, a tape, an optical disk, and the like can be considered as an IO device.
How many song storage units are integrated on a memory chip, and multiple binary number of binary information: 0 or 1 can be stored. From the type of devices used, it can be divided into MOS type, TTL type, ECL type. In the MOS-type memory chip, according to the principle of storage information can be divided into: static memory, dynamic memory.
Make as a CPU can directly program access to a memory: A basic requirement is to directly access any unit in the addressable space, and the storage time required to access any unit is independent. This approach is called an access method. The semiconductor memory can be implemented, so that the readable-writable semiconductor memory is often referred to as RAM. Only by reading, the memory that cannot be written is referred to as a ROM under normal operating conditions. RAM is divided into: Static RAM Chip (SRAM), Dynamic RAM Chip (DRAM)
Semiconductor read-only memory chip: Mask mode read-only memory MROM. Program (primary programming) read-only memory PROM. Programmable read-only memory EPROM. Electrical interpolation overwrites read-only memory EEPROM.
Memory is the programs and data used to store microcomputers. The memory consists of many units, and each unit stores a set of binary numbers. The microcomputer specifies that each of the storage units stores 8-bit binary numbers. The 8-bit binary number is defined as a byte. To distinguish each storage unit, each storage unit is given to different numbers. People call the number of the storage unit's number. The address number of the memory is started by 0, and the address order is arranged down. For example, the memory address of the 8088CPU is from 00000H ~ FFFFH, a total of 1 megabyte storage unit, referred to as memory can reach 1 megabyte.
As described above, the address of the storage unit is generally represented by hexadecimal numbers, and a set of binary (or hexadecimal) represented by each memory address is stored. The content of this address is often referred to. It is worth noting that both the address of the storage unit and the content in the address are different. The former is the number of the storage unit, indicating a location in the memory, while the latter represents the data stored in this position. Just as one is the room number, the other is the same as those living in the room.
