IDE Channels

[Steve Paddock]

Some advice please.

I have 2 IDE Hard Drives and 2 DVD Drives (DVD ROM and DVD Writer). "C"
Drive is connected as the Master on Primary IDE Channel. What is the best
way to configure the remaining drives. Most data transfer occurs between the
2 hard drives, but I would still like to keep a decent transfer rate between
the "C" drive and DVD Writer.

Thanks for any help

 

[Cari \(MS-MVP\)]

Personally I would have both hard drives as Masters and both optical drives
as slaves, but opinions vary. Just ensure you use 80 wire cables and you
should be fine.

 

[francis gérard]

Some advice please.

I have 2 IDE Hard Drives and 2 DVD Drives (DVD ROM and DVD Writer). "C"
Drive is connected as the Master on Primary IDE Channel. What is the best
way to configure the remaining drives. Most data transfer occurs between
the 2 hard drives, but I would still like to keep a decent transfer rate
between the "C" drive and DVD Writer.

i would put the hard drives on IDE channel 0, configure your boot drive as
the master, the other as slave. put the two optical drives on IDE channel
1, configure the dvdrom as master, the writer as a slave.

in terms of performance, the common school of thought is, don't mix devices
with varying UDMA speeds, BUT that is a non-issue nowadays because newer
mainboard chipsets allow each device on an IDE channel to be individually
programmed (for its maximum transfer mode), so technically-speaking, you can
arrange the drives in any configuration you want and they will all operate
at their maximum rated transfer rates. personally, i still prefer to have
the hard drives on their own IDE channel and the optical drives on another,
that makes device enumeration (in the BIOS and Windows) more logical.

notes - 1. you *must* use 80-conductor ultraATA cables for UDMA modes 3, 4
and 5, the hard drives will likely be UDMA5 and the optical drives will be
UDMA2 or higher. 2. the hard drives probably support CS-mode (cable
select), which means they don't need to be jumpered for master/slave
operation IF a proper CS-supporting cable is used, simply configure both
hard drives for CS mode, their position on the cable determines their role
(master/slave), the drive on the end of the cable becomes a master, the one
on the middle connector is a slave. some optical drives also support
CS-mode, so configure yours that way too, if supported.

here are a couple of good articles on IDE cabling, in case you're
interested:

http://www.pcguide.com/ref/hdd/if/ide/confCable80-c.html

http://www.pcguide.com/ref/hdd/if/ide/conf_CS.htm

 

[NoNoBadDog!]

Cari offers one solution, however I would recommend both HDD on the Primary,
with the fastest as Master, and the Opticals on the Secondary, with the
fastest as primary. Most Optical drives are DMA 2 or DMA3, while most HDD
are DMA5. The transfer rates will suffer if the drives are mixed on the IDE
channels. A simple HDD tach utility will confirm this. On most modern
motherboards, it is the recommended procedure to Put HDD with HDD and
Optical with Optical. This will optimize date rates per IDE channel.

Bobby

 

[francis gérard]

Cari offers one solution, however I would recommend both HDD on the
Primary, with the fastest as Master, and the Opticals on the Secondary,
with the fastest as primary. Most Optical drives are DMA 2 or DMA3, while
most HDD are DMA5. The transfer rates will suffer if the drives are mixed
on the IDE channels. A simple HDD tach utility will confirm this. On
most modern motherboards, it is the recommended procedure to Put HDD with
HDD and Optical with Optical. This will optimize date rates per IDE
channel.

bobby, this is no longer true with modern chipsets, it *was* true with older
mainboards that mixed-mode devices on the same IDE channel would be limited
to the speed of the slowest device on the channel, but that is now in the
past, and has been for some time.

 

[francis gérard]

notes - 1. you *must* use 80-conductor ultraATA cables for UDMA modes 3, 4
and 5, the hard drives will likely be UDMA5 and the optical drives will be
UDMA2 or higher. 2. the hard drives probably support CS-mode (cable

[...]

ooops typo, DMA2, not UDMA2

 

[francis gérard]

and FYI...
here is an article regarding independent device timing:
http://www.pcguide.com/ref/hdd/if/ide/confTiming-c.html

 

[francis gérard]

Some advice please.

I have 2 IDE Hard Drives and 2 DVD Drives (DVD ROM and DVD Writer). "C"
Drive is connected as the Master on Primary IDE Channel. What is the best
way to configure the remaining drives. Most data transfer occurs between
the 2 hard drives, but I would still like to keep a decent transfer rate
between the "C" drive and DVD Writer.

i should have read your article more carefully, i missed the part where you
said that "most data transfers occur b/w the 2 hard drives," in which case,
the optimal configuration, in terms of maximum performance, would be to have
the two hard drives on *separate* IDE channels. the reason being that in a
master/slave configuration, only ONE device at a time may transfer data
while *sharing* a channel. this is an inherent limitation in the IDE spec.
however, two drives on *separate* IDE channels can simultaneously transfer
data. ideally, you would use a separate IDE channel for each device (no
slave/sharing), that will provide maximum performance, since they all
operate independently and simultaneously. Adaptec and several other
hardware vendors make add-in IDE controllers with multiple channels (4 or
more), so that may be an option you wish to pursue if maximum performance is
an issue. the add-in IDE controller can be used in conjunction with the
integrated controller on the mainboard, for example, with a 4-channel add-in
controller, you would end-up with 6 IDE channels (up to 12 devices in a
master/slave configuration).

the following may help illustrate this better:
http://www.pcguide.com/ref/hdd/if/ide/conf_Performance.htm

 

[Steve Paddock]

Many thanks for all the hints tips and advice. Will now start reading all
the articles and then sit and consider what I really want.
Thanks again
Steve

 

[NoNoBadDog!]

Thanks...I have added it to my reference material...

Old habits die hard...but at least I learned something today.

Bobby

 

[francis gérard]

Thanks...I have added it to my reference material...

Old habits die hard...but at least I learned something today.

life's a school... we're all students

 

[Nathan McNulty]

One other thing to note. Cari mentioned putting the hard drives on two
separate controllers. This can greatly improve system performance
especially if you make large use of the swap file (put the swap file on
the hard drive that doesn't contain Windows). This also used to be very
true, but as the amount of system memory continues to increase, the use
of the swapfile is decreasing more and more.

I always used to put the HD as Master on Primary and both Optical Drives
on Slave. Now with SATA becoming a standard, seems like things are just
getting easier

 

[Jon Erlandson]

Many thanks for all the hints tips and advice. Will now start reading all
the articles and then sit and consider what I really want.
Thanks again
Steve

Another bit of info and a good article that explains some things can be
found at http://www.pcguide.com/ref/hdd/if/ide/conf_Performance.htm ,from
which comes.. "Master/Slave Channel Sharing: By its very nature, each
IDE/ATA channel can only deal with one request, to one device, at a time.
You cannot even begin a second request, even to a different drive, until the
first request is completed. This means that if you put two devices on the
same channel, they must share it. In practical terms, this means that any
time one device is in use, the other must remain silent. In contrast, two
disks on two different IDE/ATA channels can process requests simultaneously
on most motherboards. The bottom line is that the best way to configure
multiple devices is to make each of them a single drive on its own channel,
if this is possible. (This restriction is one major disadvantage of IDE
compared to SCSI). An add-in controller like the Promise "Ultra" series is a
cheap way of adding extra IDE/ATA channels to a modern PC. "