[ILUG] Re: [slightly OT] IDE Speed on 486?

[Thomas Ribbrock]

On Sat, May 27, 2000 at 02:36:30AM +0100, Niall O Broin wrote:
 
> I wouldn't blame your mail downloading slowness on the drive - a don't think
> your modem is outrunning even the slowest drive, and even if it were,
> files saved to disk are first saved in RAM so it would be the flusing
> process that would be slower, rather than your email download.

Ok, I should've supplied more detail. Yes, I think, it is indeed the
flushing which takes longer, 'cause what I observe are "download bursts" of
several mails in quick succession (about as fast as on the P133 I was using
before), interrupted by prolonged hard drive activity. That hard drive
activity (which I presume is the flushing) is what takes significantly
longer on the 486 than on the P133, thus overall prolonging the time it
takes to get all mails from the ISP's POP3 server. Hence, I was trying to
speed this up or at least to find out whether that's all I can expect.
I ran top during the download to monitor the load, and it rarely gets higher
than 0.5 (486DX2/66) and no swap is used (that machine having 24MB RAM), so
I don't think it's any of the "usual suspects"... :-}

I experimented a bit more with hdparm, among other things enabling 32bit
data transfers (which should be possible, with the IDE interface running of
the Vesa Local Bus), however to no avail. The IDE chip is a Promise 2020.

I also experimented with an old ISA IDE card I have, running on a slightly
overclocked (33MHz / 3 = 11MHz) ISA bus. That gave me 1.6MB/s as opposed to
the 1.4MB/s I'm seeing on the VLB card.
Wouldn't you normally expect the VLB card to be faster with VLB being 32bit
and running at the full 33MHz as opposed to ISA's 16bit and nominal 8MHz? I
also browsed through the ide documentation of the kernel sources (I'm
running 2.0.38 on that machine) and found something about "compile time
32bit data transfer option for VLB", however, I didn't find any reference as
to how to enable this - if it exists...

Anybody out there with experience on VLB machines?

Cheers,

Thomas
-- 
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      Thomas Ribbrock    http://www.bigfoot.com/~kaytan    ICQ#: 15839919
   "You have to live on the edge of reality - to make your dreams come true!"