Some info concerning Serial ATA

remixme · Post by **remixme** » Sat Jan 18, 2003 5:38 am

I saw a thread about serial ATA, and just wanted to clarify a few things....

In the current state of affairs, motherboard and hard drive manufacturers are trying to rush serial ata product to the market, here are the consequences of this.

Firstly to the best of my knowledge, at the moment any serial ATA controller uses the pci bus to communicate with the southbridge, unlike intels parrallel interface which are built into the southbridge. The other way that they put serial ATA onboard is to use translator chips to convert between the parrallel interface built into the motherboard and serial ATA, unfortunetely you then lose a parrellel controller.

The flipside of the coin is that some harddrive manufacturers are just simply converting their drives by adding chips to translate between parrallel ata and serial ata, just so they can offer a serial ata interface.
But fortunately there is very little performance degredation, but its certainly not the increase everyone was hoping for.

In Spring intel will release its new chipset 'springdale' which amoungst other things will integrate serial ata into the southbridge, with 'no conversion!'.

Harddrive manufacturers have readied native serial ATA drives, which will become mainstream right about the same time.

But unfortunetely the real performance boost comes from the special features of serial ATA, not the bandwidth, just because theres 150Mb/s of bandwidth that won't make your drive go any faster than ATA133.

The peformance increase comes from things such as special command cueing features, which are normally only found in the realms of scsi, and drives will be hot-pluggable another feature handed down from scsi.

But yet again even the native serial ATA drives coming out in spring will not implement these new features, we will probably have to wait till the second quarter till we these those kind of drives, and that is when the performance increase will come.

huffcw · Post by **huffcw** » Sat Jan 18, 2003 1:58 pm

On 2003-01-18 05:38, remixme wrote:

Firstly to the best of my knowledge, at the moment any serial ATA controller uses the pci bus to communicate with the southbridge, unlike intels parrallel interface which are built into the southbridge.

My understanding is that all hard drive interfaces (whether it is serial ATA or parallel IDE) use PCI resources???? On all motherboards I have come across, the Intel IDE controller resides on the PCI bus plus uses an IRQ.

Is there something I am missing here?

remixme · Post by **remixme** » Sat Jan 18, 2003 2:54 pm

Well yes the parrellel controller is strictly speaking a pci bus device, however the devices built into the southbridge are on a seperate pci bus, to that of your add-in pci cards.

That way you still get the full pci bandwidth for your add in pci cards.

At the moment Serial ATA and any type of onboard raid, unfortunetely have to interface with the other pci bus used for add-in components

This link may clarify
http://www.sharkyextreme.com/img/2003/0 ... iagram.gif

<font size=-1>[ This Message was edited by: remixme on 2003-01-18 14:56 ]</font>