Intro to Computer Busses

Описание: Put simply the connection between two or more componets. This is how they are talking to each other. There are different types of buses for different things. It would be slow to use USB for everything and expensive to use AMD infinity fabric for everything. Buses give us the right communication for the right devices =)

Jon Von Neuman bus! Start studying this.
A system bus is simply the actual connection between two devices. Making these standardized helps us to easier learn about them and making a scalable model for designing and producing functional computers. A bus; much like the ones on the street carry important things between important places. The buses carry in an orderly fashion and things always get there in the same state they went on. A case example is I don’t have to worry about switching legs with the guy sitting beside me or the nose of a grandma behind me. Things all just kind of work.
A computer bus had to be invented for a lot of reasons in the beginning; Random Access Memory, Storage, Processing might all be separated across multiple different physical machines. That connection between the machines was called the bus. So instead of making dedicated connections for all these components to talk to each other making 9 components. We can make 6 components; cpu,memory, i/o and a bus for control, address, and data. Buses make things easy, scalable and efficient. To illustrate, think of a CPU that is able to process data at a speed of 5 gigahertz(this is like a mid tier gaming machine) now think of how to effectively feed that processor 5 billion times per second. We do that with really fast buses(among other things).
There are a few different types of buses I want to touch on before I go into specific examples. System Bus is the communication between the CPU, memory, and possibly storage. A Expansion Bus would be used for add in cards like graphics, networks and sound. A peripheral bus may be used for anything going outside of the case, Mouse, keyboard, printer etc fit in this category.
These standards are defined by companies and then manufacturers can choose to follow them or find other bus. They are not in the business of modifying them. Buses are defined by their respective makers on 5 layers. Physical, Link(flow control), Routing Layer, Transport Layer, Protocol Layer These are the ways that a PCI-SIG would define the standards for the bus architecture. InfiniBand is the interconnect for high performance AMD server CPUs and the standard is defined by AMD. Intels version of this is the Intel Ultra Path Interconnect. These are the connects between the memory controller, the processing cores and the caches that are on a CPU which is developing in much more than a cpu; Buses are still used between devices on a single chip. For example my laptops video card is integrated onto the CPU die and it communicates via a PCI-Express 16 gen 3.0 bus even though it is on the same chip.
Now we are going to unpack system bus, expansion bus and peripheral buses. System bus is used for connecting things like the processor chipset and the processor it is also used for standardizing how CPUs talk to RAM. HyperTransport was my first introduction to buses on computers. My computer had a big old sticker saying it was proud it had a 2000mhz system bus for moving stuff around within the computer. Intel made Quick Path Interconnect for its system bus. Now a days we have Intel Quick Path Interconnect. These are extremely high bandwidth buses used for transferring a lot of data usually to multiple different devices.
Expansion Bus - This is the elephant in the room when talking about buses. This is the connection between your graphics card to your CPU. The PCI-Express is a serial connection with bidirectional lanes meaning they can talk both ways at the same time and it is made scalable up to 32x lanes but typicalling this is maxed out to 16x in computer system. That is 16 parallel high speed interconnects making for huge bandwidth that is really only maxed out by high performance networking and data transfer. There are other but this one is important
Peripheral Buses - USB anyone?? USB actually stands for Universal Serial Bus. It is a bus for plugging in a multitude of devices. We also see things like networking and wifi. So in summary a bus is how things are talking to each other and is a component that is connecting stuff as well. Thanks for watching byee.