Well...I am just wondering how this work...I know that the PCI bus connects the RAM to the CPU but I never know that the hard drive is connected to the motherboard through the PCI BUS. Isn't the harddrive connected to the mobo with the IDE cable or sata cable? How can the harddrive be connected to the MOBO through the PCI bus? If somebody could provide me with a pic, that would be really helpful.
The ports on the motherboard for the hard drives are actually wired into an invisible PCI "slot" on the board. Just like anything you might plug into the PCI slots, the IDE/S-ATA ports on the hard drive are connected to a data port controller, which is wired into the PCI bus in the same way the PCI slots are.
So you mean today, the harddrive is still connected via the port through the PCI bus? BTW, when you means the port, you mean the connector on the mobo right? Besides, what is controller? I know that the controller is to control the flow of data between the device and the PC but if you really wanna identify it on the motherboard, where will it be? And what does it look like?
That's correct. Motherboards have a controller for hard disks built into them which is effectively like an onboard version of a PCI S-ATA+IDE card. For the majority of boards, this is located within the southbridge (also known as Interface Controller Hub) - high end boards contain additional controllers, as the southbridge controllers are typically limited to 6 S-ATA ports.
Well...Is the controller just a chip built within the southbridge or is it a chipset built within the southbridge? Most of the people usually refer to the controller as the connector interface. They often say the 24 pin connector is the controller for the harddrive or harddisk. Another question is since the controller is built within the southbridge, what about the controller of the harddisk itself? It is built within the harddisk right? And what about the other controllers such as keyboard controller, floppy disk controller, and video controller? I AM JUST WONDERING WHERE THEY ARE LOCATED?
Think of the HDD controller a little bit like a GPU. You can have a dedicated one in a slot, or you can have one as part of the motherboard's own chip. The difference is, you can also find HDD chipsets on their own on motherboads, since Intel's ICH chips are limited to 6 S-ATA ports. The 24-pin connector serves a wide variety of purposes, part of the CPU's power, it powers the PCI express slots (not all the power a graphics card uses goes through the PCIe connector), it powers the RAM, and all of the controllers on the board, from the memory & PCI express controllers, to the S-ATA and IDE connections, the USB, the firewire, onboard audio, etc. etc. Anything the motherboard does that needs power (i.e. anything the motherboard does full stop), the power comes from the 24-pin connector. The controller for a hard disk is easy to spot, just look underneath
The hard disk: http://upload.wikimedia.org/wikipedia/commons/2/2d/Samsung_HD753LJ_02-Bottom.jpg More difficult with WD drives, as with those the controller is on the opposite side of the PCB and thus hidden from view.
Most (if not all) modern mainboards have gone to PCI-e based "invisable" sockets, as 32bit/33mhz PCI cannot keep up with even one fast SATA drive. As a side benifit, this requires fewer traces on the PCB...leading to lower production costs.
Well...To confirm one more time to see if I really get what you said Sammorris... When you talked about the "port on the motherboard that is wired into the invisible PCI slot" and "the IDE/S-ATA ports on the hard drive are connected to a data port controller, which is wired into the PCI bus". What springs in mind is, DO you mean the connector on the motherboard that is wired into the invisible PCI slot? So by saying invisible, it is apparently that the PCI slot cannot be seen. Although this cannot be seen, do we still know where it is located? if so, where? And then when you mentioned ""the IDE/S-ATA ports on the hard drive are connected to a data port controller, which is wired into the PCI bus", do you mean the connector of the IDE harddrive? For this question if my assumption is correct, please respond yes, if it is incorrect, please tell me why not. Here is my assumption: - The harddrive is connected to the motherboard connector with the ribbon cable. Then the connector of the motherboard is wired into the invisible PCI slot, and that PCI slot will communicate with the PCI bus, and then the PCI bus will be the mean to communicate with other components. That is why the book said the harddrive is connected to the motherboard with the PCI bus?
These "invisable" slots can be inside the southbridge itself, or they can be going seperate chips on the mainboard. There is nowhere that even resembles what you would solder a slot to...the most you might see is some of the traces, and unless you know your stuff, you wouldn't even know that those traces were for this. Since PCI is ancient history, I will discuss how PCI-e works...the chipset provides lots of PCI-e channels, some devices such as video cards can use 16...others can only use 1. Rather than running these traces to slots, these traces are run to ATA and SATA controllers that convert the signals to and from the ATA and SATA standards...these controllers may be inside the chipset, or elsewhere on the mainboard. These controllers connect to the SATA and ATA plugs, that connect to the ribbon cables, and in turn connect to the hard drive, where another controler converts the signals to something the hard drive can use.
Thanks killer bugs and that is what I thought the same that goes for the PCI. Now that it easier to proceed with the rest of the book and hopefully I could understand that better to build my ultimate PC.
