Mailinglist Archive: opensuse (3337 mails)

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Re: [SLE] DMA in SUSE Linux?
  • From: Jerry Feldman <gaf@xxxxxxx>
  • Date: Thu, 6 Apr 2006 12:02:04 -0400
  • Message-id: <200604061202.04996.gaf@xxxxxxx>
On Tuesday 04 April 2006 11:02 pm, Shriramana Sharma wrote:
> Forgive the question of ignorance:
> Does (SUSE) Linux have this Direct Memory Access (DMA) thing or not?
> Windows seems to have it, and while I am not saying that Linux should
> have everything Windows does, I find that accessing optical discs from
> Linux is somewhat slower than from Windows.
The question has been answered in the previous posts, but I would like to
add a somewhat political comment here.
DMA is a feature of the hardware drivers and has been a feature in Linux
probably since 1991. Historically, in the past there was a hardware problem
with some IDE controllers so Linux was shipped with DMA turned off (back in
2.2 kernel time frame I believe). More recent releases (SuSE 9+) have
shipped with DMA generally turned on for HD, but as mentioned otherwise,
turned off for optical devices) it is easily configurable through YaST.

Additionally, Linux disk I/O has also been shown to be faster than Windows
I/O, even when reading from or writing to Windows native file systems. Both
Linux and Unix have a number of kernel buffers that are used by Linux and
the drivers to buffer all the I/O.
Jerry Feldman <gaf@xxxxxxx>
Boston Linux and Unix user group PGP key id:C5061EA9
PGP Key fingerprint:053C 73EC 3AC1 5C44 3E14 9245 FB00 3ED5 C506 1EA9

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