Archived from groups: comp.sys.ibm.pc.hardware.storage,alt.comp.hardware.pc-homebuilt,alt.comp.hardware.overclocking.amd,alt.comp.hardware (
More info?)
Mark M wrote:
> On Wed 17 Aug 2005 06:05:30, David Maynard wrote:
>
>>fj wrote:
>>
>>
>>>"Rod Speed" <rod_speed@yahoo.com> wrote in message
>>>news:3mdtk2F16h3jdU1@individual.net...
>>>
>>>
>>>>Derek Baker <me@xyzderekbaker.eclipse.co.uk> wrote:
>>>>
>>>>
>>>>>"Impmon" <impmon@digi.mon> wrote in message
>>>>>news:rs73g1dko9d9r030l9dbqe3hebisb60lam@4ax.com...
>>>>>
>>>>>
>>>>>>On Mon, 15 Aug 2005 22:03:59 +0100, Larry
>>>>>><nomail.thank.you@mail.com> wrote:
>
>
>
>>>>>>>Are the following true for my PC (2 years old with 2 IDE
>>>>>>>ports and no SATA) and it runs WinXP:
>
>
>
>>>>>>That statement has been around for almost as long as ATA
>>>>>>CD-ROM have been around. But I don't know if anyone
>>>>>>actually used benchmark with HD and CD-ROM on same IDE cable
>>>>>>and then again with those 2 separate to see if there's
>>>>>>difference in HD performance.
>>>>>>
>>>>>>For me, it's just more convenient to have them on separate
>>>>>>IDE because I have 2 HDs on primary channel.
>
>
>
>>>>> Surely that's slow for copying from one HD to the other?
>
>
>
>>>> Nope, because most apps that are used to do
>>>> the copying dont overlap access to both drives.
>
>
>
>>> Just to clarify. Would 2 drive, RAID 0 performance be the same
>>> if the two drives were master/slave vs one on each IDE channel?
>
>
>
>> No, because IDE cannot talk to two devices on the same channel
>> at the same time but it can if they are on separate channels.
>
>
>
> So from what you say, if I have an XP system partition on one hard
> drive then the swap file (assuming I want to fiddle with placing my
> swap file) should not only be on another hard drive but that other
> hard drive should be on another IDE channel. Is this correct?
In theory it would be better but the majority of the speed increase from
putting it on a second drive is reduced latency from head movement.
Say the swap file is at the front of the first drive and you're loading a
program located in the middle of the first drive (as in a one drive
system). The heads are slamming back and forth between the loading program
and swap file; and head movement is agonizingly slow compared to read/write.
Even if the drive is on the same channel, if the swap is on a second drive
then it's head can stay in the swap area while the other drive's head stays
in the program area and the system doesn't have to wait for them to run
their little butts back and forth across the drive.
In normal use you would probably never notice the difference between the
same or different channels, however, because the read/write overlap, or
lack thereof, is such a small portion relative to everything else going on.
(A time critical application, or large transfers, might though).
RAID 0, the question you asked, is a different matter as the whole point to
it is simultaneous access to make the array look like a faster 'single'
drive. I.E. a simultaneous read from two drives is theoretically twice as
fast as two sequential reads. You get 'twice' the data in the same time as
'one read' (to both drives).
On the other hand, if it has to read/write them sequentially, being on the
same channel, then it's no faster than one physical drive, since sequential
access is sequential access, and there's no point to it. The only thing
you'd get out of it is the worst of everything: sequential access like a
'normal' drive, no 'second drive' to put the swap file on because it's in
the RAID array, and lower reliability due to the added feature that if one
dies you loose everything on both.
>
> ----
>
> I also use a PCI card to give me an extra two IDE channels. The card
> is based on the Silicon Image 0680 Ultra-133 chip.
> (I don't use its RAID capability. http://tinyurl.com/a685d)
>
> In terms of performance does it make a difference if a 7200rpm hard
> drive is on one of the two IDE channels on the motherboard (whose VIA
> Via 266A/8235 chipset provides ATA133) rather on one of the IDE
> channels on my adaptor card?
Just off hand I can't think of any reason why it would make a difference
one way or the other.
>
>
> Thanks for any info
>
> Mark
>
>
>
>
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