Re: DMA or not DMA...

[nathan@visi.com (Nathan Mates)]

In article <5mhncb$25jk@uni.library.ucla.edu>,
 <pubpc1@library.ucla.edu> wrote:
>True.  The point is, however, that in random read/write, a major
>part of the time is taken to position the read/write head over
>the platters.  Thus, in such operations the speed gained by DMA
>is only a fractional gain (since the majority of the time is still
>spent on head positioning).  In sequential access, head positioning
>time is mostly taken out of the equation, so the DMA speed gains
>are more apparent.

   Looks like you haven't read a thing I've said, so blinded are you
with your "sour grapes" covering up for your choices. I provided hard
numbers on DMA On/Off booting, with facts as to the nonlinearity of
that. You shoot back with irrelevant hot air.

   Scott, get your head out of wherever it is, and listen to the
facts: DMA HELPS A LOT.

   I'll say it again: 25% slowdown on booting IS significant, without
DMA. Adding 5 seconds to the boot (18->23 seconds) is based on one
thing and one thing only: no DMA. I don't care if you think the HD is
seeking a lot, it's STILL got to transfer that data around,
eventually, and that's where DMA helps a damn lot.

   Judging by the amount of used memory, probably somewhere between
3/4 and 1.5MB was transferred from my HD to the GS's memory. It
matters not what speed that data reached my HD card; the transfer took
longer. Significantly and noticeably longer. 

   Scott Gamon, if and when you have some hard numbers, not vaporous
bull**** to try and defend an stupid position you've staken out for
yourself, then you might be able to speak on this subject. Until then,
stop living in your fantasyland that you can lose DMA without any
noticeable performance hit.

Nathan Mates

--
<*> Nathan Mates http://www.visi.com/~nathan/      <*>
# What are the facts? Again and again and again-- what are the _facts_?
# Shun wishful thinking, avoid opinion, care not what the neighbors
# think-- what are the facts, and to how many decimal places?  -R.A. Heinlein