ata66 vs ata33 is it really faster?

[bdog]

I have tried and tried to get linux running on my bp6 with my hd on the ata66 controller. I am about to give up and switch the hd over to the ata33 controller. It works fine on ata66 in windows. Will this change really cut my hd performance in half? It seems like I once heard that 66 isn't really that much faster in real world, only in theory.

[Apostle 83]

bdog,

linux does not yet support ata66

[seti]

Even the best ATA drive can't read off the platters as fast as 33mb/s. So the only speed advantage is found when the requested data is already in the HD cache. This really doesn't happen enough to make much of a tangable performance difference at all. Once drives can read off the platter over the 33mb/s barrier, ata66 will come of age.

[bdog]

Thanks for the replies. I knew linux did not support ata66, but on my old mobo, the ide port was ata66 and it worked. I guess it just defaulted to ata33. I just wanted to keep ata66 in windows and have the drive work in any mode in linux. But since the performance difference is negligible, I will just move it over to the ata33.

[hd581]

It does appear to have a higher transfer rate, but as you'd expect, access times are not improved.
http://www.firingsquad.com/hardware/fireballpluska/page6.asp

Why is that? They've been spinning platters faster and faster, making hard drives larger and larger and yet they can't seem to move that head any faster than about 4.5 ms.

[Dominus]

Apostle 83, Linux *does* support ATA/66. I'm running it right now.

As for ATA/66 on a BP6, it's been done, but I'm not sure how. Many of the regulars at the http://www.arstechnica.com OpenForum have done this successfully, so there would definately be a good place to look.

Beware: the natives there are *very* unfriendly.

[CMonster]

seti - right on, yeah 66mbps ..hehe - until the 512 cache is used up

Dominus - I was just doing some reading at the Redhat site last night, and it seems that only certain (a couple of) controlers are supported, and that support is beta in the 2.33+ kernel (kind of like Linux and USB). If you have the "Promise Ultra ATA66" then you are likely to be in luck. There was also reference to a couple of downloads but I was to bleary-eyed to remember what they were talking about...

The good news is that Linux programers are feverously working on full support for ATA66 and USB..and things are bound to improve as this movement picks up momentum.

[This message has been edited by CMonster (edited 02-06-2000).]

[Apostle 83]

who wrote that kernal? hmmm... i guess ata66 has been out long enough for someone to use the power of open source.

[Brangwen]

BDog, I have used a Promise Card to supposedly run at ATA/66. I used it with a WD ata/66 7200 rpm Expert HD. I don't know if the Promise Card or ATA/66 did much for me. I am back to using a 5400 rpm HD (the 7200 crashed and burned as did its 2 replacements from Western Digital) and it crawls compared to the 7200 rpm drive. I think I discovered, or so it seems to me, that the higher the rpms of the drive, the faster the access or data transfer. Any comments out there? I used to know this topic a lot better when I was Hell-bent on running at ata/66, but it's been a year or two.

Brangwen