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Bus Mastering vs. different IDE channels

 
 
Timothy Daniels
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      9th Aug 2003

"drumguy1384" wrote:
>
> "Timothy Daniels" wrote:
> >
> > "Ed Light" reported:
> > > Looking in device manager, there most certainly is
> > > a "VIA Bus Master IDE Controller" on my kt400 board.

> >
> >
> > The Dell tech rep reports a "2 bus mastering IDE channels
> > on the PCI bus ATA spec compliant" as well. I haven't
> > heard back from Promise or SIIG, though. Their reps
> > didn't know what bus mastering was, so they had to send
> > an email to their engineers in Taiwan. :-)
> >
> >
> > *TimDaniels*

>
> From the article you posted a link to on IDE Bus Mastering:
>
> "Bus Mastering Hard Disk: Normally this means that the drive must
> be capable of at least multiword DMA mode 2 transfers. All Ultra
> ATA hard disks also support bus mastering."
>
> Also, from that same article:
>
> "Bus mastering IDE will not help at all in the following situations:
>
> * It will not make that 100 MB transfer from C: to D: that you are
> sitting and watching go much faster at all.
> * It will not speed up DOS games.
> * It will not make applications load more quickly (unless you
> somehow are loading more than one at a time).
> * It will not speed up single applications."
>
> This article, however, was written when Windows 95 was the premiere
> OS for the PC (not a true multi-tasking OS) ... it is quite possible that
> IDE bus mastering has been improved on in the time since then. However,
> aside from higher speeds, IDE drives have not changed much, nor has
> the PCI bus.
>
> Also, you can rest assured that the Promise and SIIG controllers will
> do bus mastering. The UATA spec requires it. That's why Dell reported
> their controllers "ATA spec compliant."
>
> In fact, I have a SiS UATA133 RAID controller that would not detect the
> drives connected to it at all until I enabled "external PCI controller bus
> mastering" in the BIOS.
>
> Hope this can shed some more light.



My 2 hard disks certainly support bus mastering - they're both
Ultra ATA 133 and the same model made by the same manu-
facturer. The Dell chipset and BIOS support bus mastering in
support of ATA 33. And the Promise and SIIG Ultra ATA 133
expansion cards support bus mastering. The OS is WinXP Pro.
It sounds like everything is a go for bus mastering for both the 2
hard drives (attached to the expansion card) and the optical devices
hooked to the legacy ATA 33 bus. It may be insignificant in effect,
but bus mastering caught my attention because I felt it might
compensate for putting both hard drives on the same IDE channel
rather than give each its own dedicated IDE channel in the interest
of fast hard drive-to-hard drive volume imaging. What do you think?
If 2 HDs on the same channel could transfer data directly from one
to the other via bus mastering, might it be faster than HDs on 2
channels
that have to transfer data to and from a RAM buffer on the expansion
card or in main memory in order to transfer data from one to the other?
In other words, given 2 modern HDs in a bus mastering enabled
environment, would HD-to-HD data transfers go faster if they're put
on different channels or on the same channel?


*TimDaniels*

 
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drumguy1384
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      9th Aug 2003

"Timothy Daniels" <(E-Mail Removed)> wrote in message
news:LdqcnYoh5dHEA6miU-(E-Mail Removed)...
>
> My 2 hard disks certainly support bus mastering - they're both
> Ultra ATA 133 and the same model made by the same manu-
> facturer. The Dell chipset and BIOS support bus mastering in
> support of ATA 33. And the Promise and SIIG Ultra ATA 133
> expansion cards support bus mastering. The OS is WinXP Pro.
> It sounds like everything is a go for bus mastering for both the 2
> hard drives (attached to the expansion card) and the optical devices
> hooked to the legacy ATA 33 bus. It may be insignificant in effect,
> but bus mastering caught my attention because I felt it might
> compensate for putting both hard drives on the same IDE channel
> rather than give each its own dedicated IDE channel in the interest
> of fast hard drive-to-hard drive volume imaging. What do you think?
> If 2 HDs on the same channel could transfer data directly from one
> to the other via bus mastering, might it be faster than HDs on 2
> channels
> that have to transfer data to and from a RAM buffer on the expansion
> card or in main memory in order to transfer data from one to the

other?
> In other words, given 2 modern HDs in a bus mastering enabled
> environment, would HD-to-HD data transfers go faster if they're put
> on different channels or on the same channel?
>
>
> *TimDaniels*
>


As I've thought about it, and refreshed my memory I don't really think that
bus mastering will increase the speed of transfer between your drives ...
not as long as they are connected to the same port anyway.

Bus mastering allows a device to take over or "master" the bus (the PCI bus,
that is) if it needs it. This can make things operate more smoothly in a
multi-tasking environment. But you have to remember that you are still
dealing with only one IDE controller port.

Yes, the controller itself can "master" the bus, and because of UATA it can
also do DMA (Direct Memory Access) which means that the drive can dump data
to the memory without troubling the processor, which can also increase
performance.

None of this, however, allows the drives to talk directly to one another and
transfer data completely independently of the rest of the system. They will
still have to use a RAM buffer no matter what.

Using separate ports, however, the controller can simultaneously read from
one drive while writing to the other ... facilitating basically the same
thing as one drive speaking directly to the other. This is why it is
*always* better to have your drives on separate ports. This is the fastest
configuration.

It sounds like you have enough ports to do it this way. Use the two ATA33
ports on the mobo for your optical drives, and give each of your hard drives
a separate port on your PCI controller card. This will work the best ... for
hard drive performance anyway ... your optical drives might possibly benefit
from the increased speed of the add-in card, but probably not.

I also might suggest that you go with round IDE cables ... I run a RAID
array with two 80gig drives, each on their own port (on a RAID expansion
card), as well as a DVD-ROM and CD-RW, each with their own port (on the
mobo). Add in a floppy cable and it gets a little hard for the air to move
around in there because of all the ribbon cables (5 total) obstructing the
air-flow. I lowered both my internal ambient temperature as well as my
processor temperature significantly by switching to round cables.

Drumguy


 
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Rod Speed
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Posts: n/a
 
      9th Aug 2003

"Timothy Daniels" <(E-Mail Removed)> wrote in message news:LdqcnYoh5dHEA6miU-(E-Mail Removed)...
>
> "drumguy1384" wrote:
> >
> > "Timothy Daniels" wrote:
> > >
> > > "Ed Light" reported:
> > > > Looking in device manager, there most certainly is
> > > > a "VIA Bus Master IDE Controller" on my kt400 board.
> > >
> > >
> > > The Dell tech rep reports a "2 bus mastering IDE channels
> > > on the PCI bus ATA spec compliant" as well. I haven't
> > > heard back from Promise or SIIG, though. Their reps
> > > didn't know what bus mastering was, so they had to send
> > > an email to their engineers in Taiwan. :-)
> > >
> > >
> > > *TimDaniels*

> >
> > From the article you posted a link to on IDE Bus Mastering:
> >
> > "Bus Mastering Hard Disk: Normally this means that the drive must
> > be capable of at least multiword DMA mode 2 transfers. All Ultra
> > ATA hard disks also support bus mastering."
> >
> > Also, from that same article:
> >
> > "Bus mastering IDE will not help at all in the following situations:
> >
> > * It will not make that 100 MB transfer from C: to D: that you are
> > sitting and watching go much faster at all.
> > * It will not speed up DOS games.
> > * It will not make applications load more quickly (unless you
> > somehow are loading more than one at a time).
> > * It will not speed up single applications."
> >
> > This article, however, was written when Windows 95 was the premiere
> > OS for the PC (not a true multi-tasking OS) ... it is quite possible that
> > IDE bus mastering has been improved on in the time since then. However,
> > aside from higher speeds, IDE drives have not changed much, nor has
> > the PCI bus.
> >
> > Also, you can rest assured that the Promise and SIIG controllers will
> > do bus mastering. The UATA spec requires it. That's why Dell reported
> > their controllers "ATA spec compliant."
> >
> > In fact, I have a SiS UATA133 RAID controller that would not detect the
> > drives connected to it at all until I enabled "external PCI controller bus
> > mastering" in the BIOS.
> >
> > Hope this can shed some more light.

>
>
> My 2 hard disks certainly support bus mastering - they're both
> Ultra ATA 133 and the same model made by the same manu-
> facturer. The Dell chipset and BIOS support bus mastering in
> support of ATA 33. And the Promise and SIIG Ultra ATA 133
> expansion cards support bus mastering. The OS is WinXP Pro.
> It sounds like everything is a go for bus mastering for both the 2
> hard drives (attached to the expansion card) and the optical devices
> hooked to the legacy ATA 33 bus. It may be insignificant in effect,
> but bus mastering caught my attention because I felt it might
> compensate for putting both hard drives on the same IDE channel
> rather than give each its own dedicated IDE channel in the interest
> of fast hard drive-to-hard drive volume imaging. What do you think?


That you're getting FAR too anal.

Why dont you actually try the two configs, both on the one
ribbon cable and each on a separate ribbon cable and see
if you get any real improvement in the speed of ops where
you are sitting in front of the PC waiting for it to happen ?

If you do crude image backups much, try that too, but bear in
mind that if you have any sense you wont normally sit around
twiddling your thumbs in front of the PC waiting for the image
creation to happen, so even if you can see a small speedup with
the creation of a compressed image, its completely academic.

> If 2 HDs on the same channel could transfer data
> directly from one to the other via bus mastering,


You're getting completely confused here too. The
short story is that as long as you have DMA enabled
and in use, thats all that matters with modern hard
drives and motherboards and IDE controller cards.

> might it be faster than HDs on 2 channels
> that have to transfer data to and from a RAM buffer on the expansion
> card or in main memory in order to transfer data from one to the other?


Nope, the problem is the theoretical simultaneous access to
both drives at once. Since both drives on the same ribbon
cable cant be SIMULTANEOUSLY reading on one and
writing on the other, in theory that config will be slower.

In practice apps like Ghost dont actually attempt to
read on one and write on the other literally simultaneously
anyway. They read from one into memory, then write
from memory onto the other when creating an image file.
With quite a bit of time taken to compress the image file.

> In other words, given 2 modern HDs in a bus mastering enabled
> environment, would HD-to-HD data transfers go faster if they're
> put on different channels or on the same channel?


Separate channels will ALWAYS be theoretically faster just
because you can literally simultaneously read off one and
write on the other drive. BUT in practice very few apps actually
do that in practice, so the difference is very theoretical in practice.

And its a rare app that would even benefit from that possibility
in the real world with modern desktop systems anyway. And
what few there are that could theoretically benefit, arent normally
used with the user sitting in front of the PC twiddling his thumbs
waiting for the op to happen with a modern desktop PC.


 
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Ed Light
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      9th Aug 2003

"Rod Speed" <(E-Mail Removed)> wrote
> what few there are that could theoretically benefit, arent normally
> used with the user sitting in front of the PC twiddling his thumbs
> waiting for the op to happen with a modern desktop PC.


You just don't love your pc enough to watch! You're not one of us!

--
Ed Light

Smiley :-/
MS Smiley :-\



 
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Timothy Daniels
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      9th Aug 2003
"drumguy1384" crunched the options:>
> "Timothy Daniels" wrote:
>
> > I had planned on upgrading my system to a configuration
> > similar to yours. The only difference would be no RAID,
> > and there would be 2 internal HDs and one HD in a remove-
> > able caddy. That would mean that one of the HDs would
> > have to share an IDE channel. I *could* accommodate
> > another PCI expansion card IDE controller, I guess, but
> > that would be getting obsessive, I think.

>
> What exactly do you plan on using the removable drive for?
> Because of physical placement issues it's not going to be able
> to be slaved to either of the internal drives. It will either have
> to go on a port with one of the CD drives or on it's own port
> on the expansion card with both of the internal HDDs sharing
> the other port. Another option would be to group the CD
> drives together and give the removable HDD the free port on
> the mobo.
>
> If it's just going to be used for occasional backups (that could
> be automated to operate while you're sleeping) it might be a
> good idea to put it as master on the same port as your least
> used CD drive or put the CD drives together and put it on
> it's own port on the mobo, because the slower speed would
> not cause an issue. But if performance on that drive is a must
> then you might just give it it's own port on the ATA133 card
> and group the two internals together. That would cause file
> copies between the two internals to slow down, but would
> greatly speed up the operation of the removable drive.
>
> Truth is, for optimal transfer between all drives you would
> need another expansion card so that each drive could have
> it's own channel, but it is unlikely that you would need all of
> that performance on all of your drives... at least not enough
> to warrant the expense of another expansion card.
>
> It seems a waste to put a modern HDD on an ATA33, but
> in this instance it might be satisfactory ... depending on what
> the drive is going to be used for.
>
> It just depends on what you want to do with that removable
> drive.



OK, here're the intimate details: I do a lot of compiling and
the resulting apps use a lot of runtime support (Java, C#, C++).
There are a lot of file reads and writes. I plan to use one hard
drive for WinXP Pro and the other for Linux, with perhaps a
NickLock for switching between one and the other as the
boot drive. Each drive will use a small partition on the other
for virtual memory (swap file/page file). That is why I want to
put each drive on its own channel. I plan to use the 3rd drive
for periodic backups of the images of the first 2 drives. The
backups don't need to be attended, but I still would like them
to complete quickly as possible.

It looks like I will just have to use one of the 2 Ultra ATA133
channels for the backup drive, putting it in a caddy that will fit
in the empty 5 1/2" bay. I plan to eventually go to an external
backup drive when FireWire 800 drives appear. Promise Tech
has already announced a FireWire 800 PCI expansion card,
and a FireWire 800 external drive should be fast enough for
backups.

The existing legacy IDE channels on the motherboard will
handle the optical and Zip drives. Each of the two optical
drives will be on different channels, one channel shared with
the Zip drive.

At least that's how I *currently* plan to configure the system.
:-)


*TimDaniels*
 
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Rod Speed
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      9th Aug 2003

Ed Light <(E-Mail Removed)> wrote in message
news:(E-Mail Removed)...
> Rod Speed <(E-Mail Removed)> wrote


>> what few there are that could theoretically benefit, arent normally
>> used with the user sitting in front of the PC twiddling his thumbs
>> waiting for the op to happen with a modern desktop PC.


> You just don't love your pc enough to watch!


Never been into that sort of perverted behaviour myself.

> You're not one of us!


Thank 'god' for that.



 
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Ed Light
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      10th Aug 2003

"Rod Speed" <(E-Mail Removed)> wrote in message
news:bh3t41$u3c88$(E-Mail Removed)...
>
> Ed Light <(E-Mail Removed)> wrote in message
> news:(E-Mail Removed)...
> > Rod Speed <(E-Mail Removed)> wrote

>
> >> what few there are that could theoretically benefit, arent normally
> >> used with the user sitting in front of the PC twiddling his thumbs
> >> waiting for the op to happen with a modern desktop PC.

>
> > You just don't love your pc enough to watch!

>
> Never been into that sort of perverted behaviour myself.
>
> > You're not one of us!

>
> Thank 'god' for that.
>


Little do you know that the God Of PC's knows you scorn them while they're
crunching massive tasks.


--
Ed Light

Smiley :-/
MS Smiley :-\


 
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Rod Speed
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      10th Aug 2003

Ed Light <(E-Mail Removed)> wrote in message
news:(E-Mail Removed)...
> Rod Speed <(E-Mail Removed)> wrote
>> Ed Light <(E-Mail Removed)> wrote
>>> Rod Speed <(E-Mail Removed)> wrote


>>>> what few there are that could theoretically benefit, arent normally
>>>> used with the user sitting in front of the PC twiddling his thumbs
>>>> waiting for the op to happen with a modern desktop PC.


>>> You just don't love your pc enough to watch!


>> Never been into that sort of perverted behaviour myself.


>>> You're not one of us!


>> Thank 'god' for that.


> Little do you know that the God Of PC's knows you
> scorn them while they're crunching massive tasks.


Little do you stupid god botherers
know what that god thinks of you.


 
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Timothy Daniels
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      10th Aug 2003

"Rod Speed" purred:>
>
> Makes a hell of a lot more sense to just ensure plenty of
> physical ram so you dont use the swap file much at all.
>
> Physical ram will always be MUCH faster than any farting
> around you could ever do with controllers and hard drives.



I'm currently maxed out on what Dell says is the max amount
for the system - 384G. I've read from several posters who
say twice the amount will work (768G) if I install the latest
BIOS - which I plan to do.


> Pointless bothering.
>
> Pointless anal if they aint attended.
>
> And real backup as opposed to mindless image backup
> of the entire drive will speed things up MUCH more too.
>
> Complete waste of time/money.
>
> And get to wear the deficiencys of those massive kludges.
>
> The current firewire is perfectly adequate for that.
>
> A standard firewire external is plenty fast enough for backups.
>
> Mindlessly anal. Wont make a scrap of difference because
> optical drives are MUCH slower than the channel bandwidth.
>
> That piece of **** should be filed in
> the round filing cabinet under the desk.
>
> Guess you could well do without a vacuum cleaner.
> You can just zoom around the floor on your arse instead |-)




Hee, hee. Your sweet nothings are always welcome, Rod.


*TimDaniels*
 
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Rod Speed
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      10th Aug 2003

Timothy Daniels <(E-Mail Removed)> wrote in
message news:(E-Mail Removed)...
> Rod Speed wrote
>> Timothy Daniels <(E-Mail Removed)> wrote


>>> I do a lot of compiling and the resulting apps use a
>>> lot of runtime support (Java, C#, C++). There are a
>>> lot of file reads and writes. I plan to use one hard
>>> drive for WinXP Pro and the other for Linux, with
>>> perhaps a NickLock for switching between one and
>>> the other as the boot drive. Each drive will use a small
>>> partition on the other for virtual memory (swap file/page file).


>> Makes a hell of a lot more sense to just ensure plenty of
>> physical ram so you dont use the swap file much at all.


>> Physical ram will always be MUCH faster than any farting
>> around you could ever do with controllers and hard drives.


> I'm currently maxed out on what Dell says is the max
> amount for the system - 384G. I've read from several
> posters who say twice the amount will work (768G) if
> I install the latest BIOS - which I plan to do.


Then there isnt any point in getting all anal about what drives
are on what controller to purportedly optimise swap file use.



 
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