Data transer between 2 hard disks

[Submit]

I have heard a few different opinions on this topic, so I thought I would ask here. Say you have 2 ata-100 hard disk and 2 ata-33 cd-rom devices. What would be the best way to connect the four devices in terms of the quickness of the transfer of data between the two hard disks? I have tried the following configurations:

Configuration 1
---------------------
Primary Master: hd1
Primary Slave: cdrom1

Secondary Master: hd2
Secondary Slave: cdrom2


Configuration 2
---------------------
Primary Master: hd1
Primary Slave: hd2

Secondary Master: cdrom1
Secondary Slave: cdrom2

So far I haven?t noticed a significant advantage or disadvantage to either configuration when transferring large ISO images between the two hard disks. I have heard that configuration 1 is faster since data can travel only one way on a IDE Ribbon, and that configuration 2 is faster since both of the devices on the primary channel are both ATA-100.

My guess is that since any IDE hd can only read/write a few mb/s anyway so it really makes no difference that data can only travel one way since it can travel up to 100 mb/s. But then I though that even IDE hd's can burst close to 100 mb/s so would Configuration 1 be ultimately faster because of this....

As far as Configuration 2 being faster because of having both ATA-100 devices on the same channel, I am under the impression what each device can operate at it?s own speed, whether it ATA-100 or ATA-33 so this isn?t a valid argument.

Does anyone know exactly how the data is sent and can explain in detail?

Thanks.

 

[ElFenix]

config 1 is supposed to be faster, but as you said, you're not maxing out the interface anyway.

 

[corkyg]

Originally posted by: Submit
I am under the impression what each device can operate at it?s own speed, whether it ATA-100 or ATA-33 so this isn?t a valid argument. Does anyone know exactly how the data is sent and can explain in detail? Thanks.

I don't buy that. This is why. Most mobos have one high speed ATA controller (the blue one - #1.) When a ATA 66/100 drive is connected to it, it runs at that speed (actually burst mode only). As soon as you slave a non-ATA/66/100 device to it, it reverts to the standard 33 speed. That is what makes it backward compatible.

The Secondary channel is 33 all the way, so any ATA high speed device connected to it cannot do its fast thing. It is throttled back.

The HDD transfer rate in Config 2 will be faster than Config 1. However - the CD ROM/CD-RW setup is not good because you can't rely on on-the-fly copying of a CD with the burner on the same controller.

Everything has to be a compromise.

You will hardly notice any difference in speed in either case, because the ATA 66/100 rate is only achieved in bursts - not sustained.

Based on that, I would go with Config 1. Ideally I would go Config 2 and remove the IDE CD/RW drive and out it in an external USB 2 or Firewire case.

 

[gf4200isdabest]

Configuration 1
---------------------
Primary Master: hd1
Primary Slave: cdrom1

Secondary Master: hd2
Secondary Slave: cdrom2

I use that cause config #2 wouldn't work on my Epox 4g4a+

 

[kgraeme]

Originally posted by: corky-g

Originally posted by: Submit
I am under the impression what each device can operate at it?s own speed, whether it ATA-100 or ATA-33 so this isn?t a valid argument. Does anyone know exactly how the data is sent and can explain in detail? Thanks.

I don't buy that. This is why. Most mobos have one high speed ATA controller (the blue one - #1.) When a ATA 66/100 drive is connected to it, it runs at that speed (actually burst mode only). As soon as you slave a non-ATA/66/100 device to it, it reverts to the standard 33 speed. That is what makes it backward compatible.

The Secondary channel is 33 all the way, so any ATA high speed device connected to it cannot do its fast thing. It is throttled back.

This used to be the case, but most motherboards in recent years have identical performance from the primary and secondary IDE controllers. So in that case, it depends on the motherboard.

 

[grant2]

There's only 1 way to know for sure- create a huge honkin' 30 gb file, get a stopwatch, and time how long it takes to copy under both configs.

We'll expect your results by sundown.

(Personally, my money is on #1 - it can stream from one HD to the other nonstop. With config #2, each HD is stalled 50% of the time.)

 

[Submit]

Originally posted by: grant2
There's only 1 way to know for sure- create a huge honkin' 30 gb file, get a stopwatch, and time how long it takes to copy under both configs.

We'll expect your results by sundown.

(Personally, my money is on #1 - it can stream from one HD to the other nonstop. With config #2, each HD is stalled 50% of the time.)

From what I understand the IDE ribbons and the controller spend most of their time waiting for one hd to read and the other write. So in fact each hd is not stalled 50% of the time.

I have a few 2gig Ghost images, I will have to do some testing tonight as well as copying cd's on the fly, and watching the cpu activity. I will post any findings when I finish.

 

[grant2]

From what I understand the IDE ribbons and the controller spend most of their time waiting for one hd to read and the other write. So in fact each hd is not stalled 50% of the time.

An IDE controller can only communicate with 1 device at a time, so if you have 2 devices on one controller, they will each be idle at least 50% of the time (averaged out).

That is the whole point of putting the HDs on different controllers, so each HD can be active up to 100% of the time.

 

[kursplat]

get an ATA100 card. put everything on it's own channel and live the good life.
good luck

 

[Submit]

Time to transfer large files between 2 hard disks is almost exactly equal. I did this twice and it was actually a few seconds faster having both hard disk on the same channel. Both of my cables are ATA-100 and both of the hard disks as WD..ATA-100

Nero burning ROM showed a message about having 2 cd-roms on the same channel but burned a copy on-the-fly just fine, with very low cpu activity, like usual.

Anyone have any insight on just how the IDE controller operates ?

 

[Submit]

BTW..either configuration bursts over 80mb/s , as that is the limit of version HD Tach which I have, for either disk.
Average read speed is the same as well.

 

[BFG10K]

This is what I use:

ATA 100:
HD1.
HD2.

ATA 33:
DVD.
CDRW.

I don't have problems with file copying, CD burning or copying disk to disk.

 

[Dre]

Western Digital recommends that you do not mix optical drives with harddrives on the same ide cable. Therefore, according to western digital, the recommend configuration is configuration 2. I don't feel like searching western digital's website for the link, maybe later or maybe someone else will.

 

[kgraeme]

From PCGuide:

• Independent Master/Slave Device Timing: Hard disk controllers on modern systems support running the master and slave device at different speeds, if one supports faster transfer modes than the other. Some systems, however, especially older ones, do not. If you are using two devices with radically different maximum transfer rates, and the chipset doesn't support independent timing, you will slow down the faster device to the speed of the slower one.
  
• Hard Disk and ATAPI Device Channel Sharing: There are several reasons why optical drives (or other ATAPI devices) should not be shared on the same channel as a fast hard disk. ATAPI allows the use of the same physical channels as IDE/ATA, but it is not the same protocol; ATAPI uses a much more complicated command structure. Opticals are also generally much slower devices than hard disks, so they can slow a hard disk down when sharing a channel. Finally, some ATAPI devices cannot deal with DMA bus mastering drivers, and will cause a problem if you try to enable bus mastering for a hard disk on a channel they are using.

 

[Submit]

So if the controller supports having, for example, an ATA-100 hd and an ATA-33 cdrom then each device will work at its own speed then it doesn't matter which configuration is used as then both will allow for all the device to operate at their maximum speeds.

Also, if there aren't any problems with DMA mode, meaning the hds run at 5 and the optical devices run at 2, then there are any disadvantages to mixing hds and optical devices.

I guess the tiebreaker is the fact the since data can travel in only one direction at a time, configuration 1 might have an advantage under heavy load.

 

[grant2]

submit, i'm surprised at which was faster, but at least now you have the answer!

 

[kgraeme]

Originally posted by: Submit
So if the controller supports having, for example, an ATA-100 hd and an ATA-33 cdrom...

There's the rub. AFAIK, there aren't ATA-33 cdrom drives. They are ATAPI, which is different. If they were ATA, then your assumption would be correct and there wouldn't be a speed issue. Unfortunately, as I posted in the reference above, there is a degredation of speed with ATA (harddrives) and ATAPI (CD drives) on the same bus.