Big talk storage 1-into the world of computer IO

The big three that make up the computer: CPU, memory, and IO.

1 bus

The bus is one or more physical wires, each of which is connected to these conductors, and only one part is received or sent at the same time.

Quorum bus: All parts are judged by the other bus, the quorum bus, or the signal given on the interrupt bus, to determine which part of the bus can be used by this moment. The resulting quorum bus or interrupt potential can be either CPU or other devices on the bus.

As shown, each part of the motherboard is connected by a bus.

PCI bus : A bus technology that is commonly used by desktops and servers to connect a South bridge to a peripheral.

North Bridge Chip : The difference between IO Bus and Ethernet hub model is that a North bridge chip is more. Because the CPU and memory are fast enough, they are connected by a single bus between the bus and the slow IO bus via a bridging chip, which is the North Bridge chip on the motherboard. The chip is connected to the CPU, memory, and IO bus.

front-end bus : The bus that the CPU connects to the North Bridge is called the system bus, also known as the front bus.

Memory bus: The bus that the memory connects to the North Bridge is called the memory bus.

Because the North bridge speed is too fast, and the IO bus speed relative to the North Bridge appears too slow, so between the North Bridge and the IO bus, often to add a network bridges, called South, in the South Bridge is generally integrated with a number of peripheral controllers, such as disk controller, the USD controller and so on.

Number of bus bits : The number of the system bus, such as 64 or 128, is called the number of bus bits.

Number of CPU bits : The number of buses between the Register and the operating unit.

The IO bus is divided into data bus, address bus and control bus. The address bus is used for addressing, the data bus is used, and the interrupt signal is controlled by the bus. The IO bus is parallel rather than serial.

2 communication between CPU, memory, and disk over the network

Because the bus on the motherboard is very short and stable, a "network" between the CPU and the storage device does not require a transport layer, but only the physical layer, the network layer, and the three-tier network.

Device mapping : Each IO device maps one or more addresses to memory at boot time, which is 8 bits long and is called an IO port. The data for this address are all redirected to the actual device on the bus by the North Bridge chip.

When the CPU sends instructions to the disk, these instructions are actually sent to the integrated controller on the motherboard South Bridge, such as the ATA controller or the SCSI controller. Let the disk read or write to a track, a sector, etc., the CPU does not need to know these, the CPU needs only to know the logical block address is read or write, so that the CPU generated this information is the disk controller driver.

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3 Summary

The network of CPUs, memory, and disks can be abstracted using the following diagram:

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Resources

"Big Talk" Storage 2-storage system architecture and underlying principle limit analysis?

Big talk storage 1-into the world of computer IO