2 replies to this topic

[ShadowFox]

The three letter acronyms... we know what the latter of the three mean but what about the other two?

I was looking for a new hard driver today and stumbled across something called and ATA, and at first hand I said "Damn that's a good buy but I don't have one of those sockets " Later I decided to so some research and see just what ATA really is

so I came to this.

ATA = Advanced Technology Attachment, that's easy enough to figure out

It's a protocol for IDE(= Integrated Device Electronics)Data-transfers

The figures ATA-133 indicate the -theoretical- maximum data transfer of the ATA-protocol.

ATA-33 -> 33 MB/s maximum data-transfer
ATA-66 -> 66 MB/s maximum data-transfer
ATA-100 -> 100 MB/s maximum data-transfer
ATA-133 -> 133 MB/s maximum data-transfer

ATA is also the same as Ultra-ATA (UATA/U-ATA) or UltraDMA (UDMA)

So the ATA/133 hard drive I was looking at will work in my computer... here are some quick pics

Here are the cables


and here are the sockets


Notice on the motherboard it says "IDE" next to the socket

So now I know, and you know too!

[Visentinel]

ATA is not the same as UATA and Ultra-DMA

they are modes of operation.

those cables u have there are the old Parallel ATA and as such are called PATA as opposed to SATA for Serial ATA.
if you are not running Bus Master mode (bad thing for performance) you end up running PIO Mode ATA

PIO modes 1 and 2
33 and 66

Bus Master Modes

Ultra ATA simply refers to supporting Ultra DMA bus mastering modes.

DMA Modes 1 2 then UltraDMA 1 2 3 4 5 6

33 66 100 133

They overlap each other

Only Maxtor drives support UDMA 133 but there has never been a drive including maxtor that actually benefit from PATA 133

Now IL explain what the actual difference is between PIO and DMA

There is a chip on your motherboard called the Direct memory Access Chip which allows hardware to skip going thru the cpu to access the systems main memory, the chip updates the cpu on the matter but other than that the cpu carries on with its own things.

When something puts info in your memory via dma and then software wants that info the cpu can later access it at the address the dma placed it, so the cpu can go on with its work while waiting for dma transfers then it can access the data and all is well.

this cuts of the round trip time massively and improves performance significantly.

AGP fastwrites is also based on DMA but with a twist.
Instead of the cpu putting data into memory then the cpu starting a memory to gpu memory transfer the cpu can directly output to the gpu memory significantly saving memory bandwidth and cutting the round trip heaps shorter.

This all runs with a mixture of Driver and Hardware support and Control

Edited by Visentinel, 13 September 2005 - 11:31 AM.

[ShadowFox]

Well, the Hard Drive I bought works and I'm happy it does.