Sign in to follow this  
jrayner

Simple Master/Slave question

Recommended Posts

Hi all,

A simple question for you, is there actually any difference (performance or otherwise) between the master and slave device assignment on an IDE port? Do requests to the master get priority or something?

I've got 2 HDDs (ATA-100) and a CD-RW & DVD ROM, is there any difference between putting an HDD as master and CD as slave (on each channel) and doing it the other way around??

Thanks for your thoughts :D

John

Share this post


Link to post
Share on other sites
A simple question for you, is there actually any difference (performance or otherwise) between the master and slave device assignment on an IDE port?  Do requests to the master get priority or something?

I have done some tests on the same drive set as "Master" and as "Slave". I did not find any performance difference. The test was done with Maxtor drives. This might be not true for other drivers or controllers.

I've got 2 HDDs (ATA-100) and a CD-RW & DVD ROM, is there any difference between putting an HDD as master and CD as slave (on each channel) and doing it the other way around??

There is no difference. I have read at some sites that if you connect ATA100 devices with a CD-ROM, the HDD might have a lower performance. In my setup, I have not found this problem.

Share this post


Link to post
Share on other sites
Guest russofris
Hi all,

A simple question for you, is there actually any difference (performance or otherwise) between the master and slave device assignment on an IDE port?  Do requests to the master get priority or something?

It is totally dependant on the components.

I've got 2 HDDs (ATA-100) and a CD-RW & DVD ROM, is there any difference between putting an HDD as master and CD as slave (on each channel) and doing it the other way around??

Thanks for your thoughts :D 

John

Not only will adding 2 drives to a chain limit the ATA-TR to lowest common denominator (usually ATA-33), the latency incurred from slaving a CDRom to a HDD will normally have a huge impact on performance (bad thing).

Download ATTO and WB99 and test your configuration with different IDE arrangements. See what works for you the best.

Thank you for your time,

Frank Russo

Share this post


Link to post
Share on other sites

Actually it doesn't have any performance impact whether you have a slave or master configuration, either cd-roms or harddrives drives, you can mix it as you like, unless you have drives that don't use UDMA.

The only thing is that IDE can only access 1 channel at a time so the devices have to wait for eachother. So of course this reduces performance. But unless you buy an extra controller, you cannot get around this limitation no matter how you connect your devices.

Hope this helps.

PS. Just reread your post, you want to connect the them as cd-rom, harddrive, dvd-rom, harddrive, if you connect the cd devices on the same channel it will screw up the copy cd to cd. DS.

Share this post


Link to post
Share on other sites
Guest russofris
Actually it doesn't have any performance impact whether you have a slave or master configuration, either cd-roms or harddrives drives, you can mix it as you like, unless you have drives that don't use UDMA.

Take a UDMA 100 controller (confirmed with 868b and SIS 735). Put a UDMA 100 HDD as master, put a UDMA33 CD as slave. Guess what? The HDD now runs at UDMA33.

This may not apply to all controllers. Maybe Promise pulled an "Adaptec" (referring to how Adaptec F'd with my reality by allowing the use of all 3 connectors on a single channel card).

Can someone (acke3) fill me in on this please? I'm feeling a little "left out" here. A link would be greatly appreciated.

Like these:

http://computers.cnet.com/hardware/0-1017-...-3939496-1.html

http://www.jsihardware.com/guides/howtohdd/2.shtml

http://www.eyo.com.au/tech-forum/archive/245691.html

http://forums.viaarena.com/messageview.cfm...0&threadid=5559

http://www.one2surf.co.uk/enduser/productl...ad/features.asp

http://www.sharkyextreme.com/hardware/guid...e_guide/2.shtml

http://www.mandrakeuser.org/docs/hardware/hide.html

http://www.dslreports.com/forum/remark,209...views~mode=flat

And so on, and so forth..

Thank you for your time,

Frank Russo

Ahh, when looking up links, I came accross this... Look at page 5. Promise "DID" do it!?!?!?!

http://www.promise.com/Products/Ultra_Tx2/...100TXLaunch.pdf

Share this post


Link to post
Share on other sites

Well I'm glad we cleared that up!! :D

Seriously though, thanks for your replies, I guess it's just suck it and see, I've downloaded WB99, couldn't find anything relavent to ATTO, so no luck there - any help anyone?

The mobo I have is a new-ish ASUS something or other - can't remember the part no. now, anyway its the DDR 266 AMD/VIA one (non-RAID - god knows why I didn't go for RAID!) so I think it should be able to cope with mix'n'match transport speeds.

Now all I have to do is work out how to get WB99 (9+MB)off my machine at work (fast internet) onto my machine at home (dial-up)!

Watch this space!

Share this post


Link to post
Share on other sites
Take a UDMA 100 controller (confirmed with 868b and SIS 735).  Put a UDMA 100 HDD as master, put a UDMA33 CD as slave.  Guess what?  The HDD now runs at UDMA33.

I did a simple test I hooked up my noname 4x4x32 cdrw drive that I bought used, it's probably a least a year old if not older, as slave and my maxtor UDMA 133 D540X as master, (as far as I know there are no UDAMA 66 cd-roms) on my Asus K7V VIA KX133 motherboard AMD Athlon 700 Mhz, UDMA 66 controller (built into the motherboard). Did the test with HD Tach 2.61

Here are the results:

Maxtor D540X (4K060H3) OS Win XP on a single drive on channel 1.

Sequental Read all tests were run 3 times just took the highest of the three.

Max. Read 35153 KB/sec avrage 27689.

Maxtor D540X (4K060H3) OS Win XP as master drive noname cdrw as slave, on the same channel. Sequental Read all tests were run 3 times just took the highest of the three.

Max. Read 36267 KB/sec avrage 27657.

Wow it's even faster, but it falls well between the error margin so I assume that the drive have the same speed.

Well after this little test, those ideas seem like old school to me, yes if you go for an UDMA 33 cable you will loose performance, but if you put it on UDMA 66/100 cable it's not a problem, as you can see.

If the CD-Rom doesn't support UDMA then yes you are correct.

Share this post


Link to post
Share on other sites

Probably a Good Real World test is to try something that accesses the Hard Drive and CD-Rom at the same time.

Get yourself a big sized Game. Setup your HD as Master on the Primary Channel and the CD-ROM as slave on the Primary channel, remove any other drives for now(unplug them). Install the game/program from the CD-ROM to the Hard Drive. Before installing the program, run a good defrag first. Install and write down the time of the installation from Start to End.

Move the CD-ROM over to your secondary channel. Remove the program, run defrag run the install with the same settings you used to the HD on the Primary Channel and see if your times are different, if so how much and is it worth any more headache.

Share this post


Link to post
Share on other sites

This is a stupid question, but how come in Win2K you have the option to set each device independently using DMA or PIO? So even if you have a HDD and CD-ROM on one channel, you can still set one with DMA and one with PIO in Win2K (in fact, on the Win2K installs I've done, more often than not it sets the CD-ROM to PIO by default for some reason, even if its running slave to a master HDD). I've never figured how this would work (and never had time to benchmark the speeds)...

Share this post


Link to post
Share on other sites

st63z, That is an interesting question. Why not make the channel either DMA or PIO... Because I know that if you pop at ATA33 Drive with a ATA100, they both will operate at ATA33. Does the same happen with PIO (when one of the two are in PIO mode)? Good question...

Share this post


Link to post
Share on other sites
st63z, That is an interesting question.  Why not make the channel either DMA or PIO... Because I know that if you pop at ATA33 Drive with a ATA100, they both will operate at ATA33.  Does the same happen with PIO (when one of the two are in PIO mode)?  Good question...

Actually, windows is set to UDMA 33 as default, has NOTHING to do with having a hardrive and cd-rom on the same channel. You must in to the registery and change it manually. I did it with Tweak XP, in Win Xp.

Read my results from my prevous post, there it clearly shows that there is no difference whatsoever, and my cd-rom did pop into UDMA Mode 4 just as my harddrive, I have UATA 66 = UDMA MODE 4.

And yes they loose a tiny performance if they are on the same channel, but as long as you don't use them simultaneously the performance decrease is

st63z, That is an interesting question.  Why not make the channel either DMA or PIO... Because I know that if you pop at ATA33 Drive with a ATA100, they both will operate at ATA33.  Does the same happen with PIO (when one of the two are in PIO mode)?  Good question...

Actually, windows is set to UDMA 33 as default, has NOTHING to do with having a hardrive and cd-rom on the same channel. You must in to the registery and change it manually. I did it with Tweak XP, in Win Xp.

Read my results from my prevous post, there it clearly shows that there is no difference whatsoever, and my cd-rom did pop into UDMA Mode 4 just as my harddrive, I have UATA 66 = UDMA MODE 4.

And yes they loose a tiny performance if they are on the same channel, but as long as you don't use them simultaneously the performance decrease is negligible.

Share this post


Link to post
Share on other sites

I'm not familiar with WinXP, but in Win2K, go to Device Manager and view the properties for the Primary and Secondary motherboard IDE controller (not the HDDs, but the controllers). There you'll see settings to set each device on each channel to DMA or PIO mode (and see the current mode being used). Just wondering why MS would set it up like this if it's physically impossible to have mixed DMA/PIO on one channel...

Share this post


Link to post
Share on other sites
Guest russofris
Just wondering why MS would set it up like this if it's physically impossible to have mixed DMA/PIO on one channel...

From what I am reading on the net... It may not be impossible. I am still investigating the issue, but I believe the world of ATA may have changed without letting any of us know about it.

Frank Russo

Share this post


Link to post
Share on other sites

Create an account or sign in to comment

You need to be a member in order to leave a comment

Create an account

Sign up for a new account in our community. It's easy!

Register a new account

Sign in

Already have an account? Sign in here.

Sign In Now
Sign in to follow this