What's the difference between ATA, SATA and IDE?

[Googer]

Originally posted by: Pariah

EIDE- is an improvement over standard IDE as it alows the hard drive to directly access the system ram with out involving the cpu like IDE did.

This is incorrect too. DMA transfers were already in the ATA-1 standard. EIDE was never an official standard. EIDE is the name WD gave to its enhanced version of the ATA-1 that contained most of the improvements that the official ATA-2 standard would have before it was officially released, and some additional features including, ATAPI support, and dual controller support. Today EIDE means nothing as it contains no additional features vs the current official ATA standard.

Thanks for the correction, My memory is fuzzy and I can not be corect 100% of the time.

 

[Tab]

If it's so hard to get parrarel devices working, why didn't computer enginners start with serial in the first place?

 

[Matthias99]

Originally posted by: Tabb
If it's so hard to get parrarel (sic) devices working, why didn't computer enginners (sic) start with serial in the first place?

It goes back and forth in the computer world (or at least has for the last 20-30 years, maybe longer).

When the ATA spec was developed, it was really hard to push very high-speed serial connections, even on the motherboard. They *had* to go with a parallel connection to get a decent transfer rate. They then stuck with it, because it worked and the entire hard drive industry (which changes much more slowly than the rest of the computer world) was doing it.

Fast-forward 25 years, and now we can make multi-Ghz serial links for next to nothing (see ubiquitous USB2.0 peripherals), whereas parallel links at high speeds start to suffer incredibly from signal degradation due to crosstalk and capacitance between the wires (which is much less of a problem at lower speeds). Serial links are generally cheaper and easier to route, so when the decision was made to replace ATA, the computer industry went with a serial protocol (SATA).

It's very much along the same lines with PCI Express and legacy PCI. Except there you'll see that to get the very high bandwidth required for some internal devices, you can tie multiple links together into 'x4', 'x8', 'x16', etc. connections.