SATA problems

[John Wendel]

Rohan Kulkarni wrote:
> Hello,
>          So will it help if I have a faster processor or I add in more 
> RAM to my system?
> 
> On 7/3/07, *John Wendel* < john.wendel at metnet.navy.mil 
> <mailto:john.wendel at metnet.navy.mil>> wrote:
> 
>     Rohan Kulkarni wrote:
>      >
>      >
>      > On 7/3/07, *Rohan Kulkarni* < rohan.ak1 at gmail.com
>     <mailto:rohan.ak1 at gmail.com>
>      > <mailto:rohan.ak1 at gmail.com <mailto:rohan.ak1 at gmail.com>>> wrote:
>      >
>      >
>      >
>      >     On 7/2/07, *John Wendel* < john.wendel at metnet.navy.mil
>     <mailto:john.wendel at metnet.navy.mil>
>      >     <mailto:john.wendel at metnet.navy.mil
>     <mailto:john.wendel at metnet.navy.mil>>> wrote:
>      >
>      >         Rohan Kulkarni wrote:
>      >         >
>      >         >
>      >         >  On 7/2/07, *Tim* <ignored_mailbox at yahoo.com.au
>     <mailto:ignored_mailbox at yahoo.com.au>
>      >         <mailto: ignored_mailbox at yahoo.com.au
>     <mailto:ignored_mailbox at yahoo.com.au>>
>      >         >  <mailto:ignored_mailbox at yahoo.com.au
>     <mailto:ignored_mailbox at yahoo.com.au>
>      >         <mailto: ignored_mailbox at yahoo.com.au
>     <mailto:ignored_mailbox at yahoo.com.au>>>> wrote:
>      >         >
>      >         >     On Mon, 2007-07-02 at 19:14 +0530, Rohan Kulkarni
>     wrote:
>      >         >      > My motherboard supports hard disk speed of
>     150MB/s but i
>      >         get only
>      >         >      > 15MB/s speed
>      >         >
>      >         >     Have you double-checked that the figures you're
>     reading at
>      >         are bits per
>      >         >     second or bytes per second?
>      >         >
>      >         >     --
>      >         >     (This box runs FC5, my others run FC4 & FC6, in
>     case that's
>      >         >     important to the thread.)
>      >         >
>      >         >     Don't send private replies to my address, the
>     mailbox is
>      >         ignored.
>      >         >     I read messages from the public lists.
>      >         >
>      >         >
>      >         >
>      >         >  Hello,
>      >         >            Yes I have checked with the motherboard
>      >         specifications.It
>      >         >  says that it supports
>      >         >            a speed of 150MB/s.It is bytes for
>     second.Though my
>      >         hard disk
>      >         >  supports native command queing my motherboard does not
>     support
>      >         it.
>      >         >
>      >         >     --
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>      >         >
>      >         >
>      >
>      >         It doesn't matter what speed your motherboard (SATA
>     controller)
>      >         supports if the disk speed is slower. What brand/model of
>     disk
>      >         do you
>      >         have? What kernel version? How are you measuring the disk
>     speed?
>      >
>      >         Regards,
>      >
>      >         John
>      >
>      >
>      >
>      >     Hello,
>      >              I have a Seagate ST3160211AS.It is a Barracuda 160GB
>     hard
>      >     disk with a
>      >              speed of 7200RPM.It supports upto 300MB/s with Native
>      >     Command Queing.I checked the average  speed of copying by
>     copying a
>      >              3GB file from one FAT32 partition to another.I got a
>      >     average speed of around
>      >              15MB/s.I have the kernel 2.6.21-1.3228.fc7
>      >                                                              Thanks...
> 
>      >
>      >
>      >
>      >       Can anyone please help me...do i need to update to the latest
>      > kernel??or do i need
>      >       to download some drivers.
>      >
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>      >
>      >
> 
>     You don't really have a problem!
> 
>     Don't confuse the maximum interface transfer speed (150 MB/s) with
>     your disk transfer speed (approx 40-50 MB/s).
> 
>     When you copy a file, you read the old file, and then you write the
>     new file, rinse and repeat until done. So your transfer speed is going
>     to be approximately 1/2 to disk speed. And now you need to add in the
>     operating system overhead, allocating blocks for the new file, and all
>     the seek time, moving the disk heads between the old file blocks and
>     the new file blocks.
> 
>     15 MB/s seems reasonable. On my box, using a single drive, I get a
>     write speed of 30 MB/s for a 3 GB file and a copy speed of 14 MB/s.
> 
>     Need more speed, get more disks and a raid controller.
> 
>     Regards,
> 
>     John

Faster processor can help lots of things, but not disk speed. More 
memory (usually) helps, the kernel can use it for disk cache if 
nothing else.

Anybody else out there got any advice for speeding up SATA drives ?

Regards,

John