Using IDE Cables... Stupid Question?

[DGauld]

having built several windows based pcs, and not really paid that much attention to the use of ide cables (lol, they just connect things together ) i have a quick question, relating to something i heard the other day...

ide cable
|=========|=====|
mobo..........1.........2

... if i have two devices, e.g. two ide hard drives, which part of the ide cable, 1 or 2 do i connect the primary master to (assuming, the two drives are pri-mas and pri-sla) - i heard that you connect the pri-mas to no2, is this true? and does it make a difference?

also, is connecting one hdd and one optical drive to the same cable a bad idea? any reasons for/against this?

cheers guys/girls

[SilentDeath]

Make sure the jumper on each device is set to either master or slave, and NOTcable select. This way it doesnt matter.

I think some opticals dontlike being connected to a hdd, Ive had drives that would not be recognied on the same cable.
I think the rule is to make sure they all operate in UDMA33,66,100, or 133. If they are PIO4 drives, they wont work with a UDMA drive. Might be wrong...

[DGauld]

what is this cable select thing? ive heard it a few times, but never thought to ask what it is...

[Captain Fizz]

|=======|===|
Mobo.......S.....M

Cable is as so:
Mobo .. Slave .. Master

So the Master always goes to the end of the cable... Slave to the middle one.

As long as your HDD is master, and Optical a slave - There is no reason not to have both devices on the same IDE cable.

I wouldn't have an often used optical drive on your OS's HDD's cable though... Only one device can be accessed at any one time on an IDE cable. So I'd have the OS HDD on it's own cable if poss.
Optical and any other HDD on the 2nd cable.
If not, as long as the optical drive is not used often, it will do no harm. (And only when in use will it slow it down at all)

And Cable Select... If you have the jumpers set to CS, when you plug the device into the slave connector - It will be a slave, if it's plugged into the master connector (end of cable) it will be a master.

[Allen]

As long as your HDD is master, and Optical a slave - There is no reason not to have both devices on the same IDE cable.

Apparantly it does, but I don't know for sure. There was a discussion a while ago where people said that having a HDD and CD/DVD on the same cable will make both devices run at the same speed as the slowest device, the CD/DVD, therefore running a HDD and CD/DVD on the same cable will slow the HDD down.

Saying that, I haven't tried it, but have always used different cables for different types of drives.

[DGauld]

yeah, what ill probably have is this...

1x 74gb raptor, sata
1x 200gb seagate, sata
1x 120gb maxtor, ide
1x dvd/cdrw, ide

ill be using the raptor as primary boot, so technically i could use 2x sata and 1x ide, but could also use 2x sata and 2x ide?

oooh, im so excited, all the parts arrive tomorrow.. its only been over two weeks!!!

[yamangman]

You should use the Maxtor as primary master and the optical drive as secondary master.

[Agent]

As long as your HDD is master, and Optical a slave - There is no reason not to have both devices on the same IDE cable.

I wouldn't have an often used optical drive on your OS's HDD's cable though... Only one device can be accessed at any one time on an IDE cable. So I'd have the OS HDD on it's own cable if poss.
Optical and any other HDD on the 2nd cable.
If not, as long as the optical drive is not used often, it will do no harm. (And only when in use will it slow it down at all)

And Cable Select... If you have the jumpers set to CS, when you plug the device into the slave connector - It will be a slave, if it's plugged into the master connector (end of cable) it will be a master.

Yes, there is a reason not to have both on the same cable.
A device on IDE can only opperate as fast as the slowest drive. So if you have a drive opperating at UDMA33 (most optical based ones), and a UDMA133 drive on the same cable, the UDMA133 drive will drop back to UDMA33.
The other point about being accessed is also a bit off. While mass data will only be transmitted during requested times, the IDE controler and the drive are talking a heck of a lot more than you give credit for. The drive will constantly be handling interupts and various none-sence the IDE controler decides it wants to generate. Just because your not copying / writing files to the drive, the computer will still be talking to it.

[Captain Fizz]

Yes, there is a reason not to have both on the same cable.
A device on IDE can only opperate as fast as the slowest drive. So if you have a drive opperating at UDMA33 (most optical based ones), and a UDMA133 drive on the same cable, the UDMA133 drive will drop back to UDMA33.

Unsure about the amount of chatter the drives will produce but the above comment was true on older chipsets - But, I am 99.9% sure it is not the case for any current chipset. (Do you have proof either way? This has been bugging me for years... )
If you check speeds, look in device manager, copy large files about, benchmark using various apps - There is no difference in speed (UDMA33/66/100/133) of the drive whether the Optical drive is plugged in or not.

Personally, if I had DGauld's drives:
Prim Mast: 1x 120gb maxtor, ide
Sec Mast: 1x dvd/cdrw, ide
And the 2 other HDD's on SATA.

I found better performance, especially between 2 HDD's (obviously really) when I had 2 HDD's and 2 optical drives:
Prim Mast - OS HDD
Prim Slave - CDRW
Sec Mast - Storage HDD
Sec Slave - DVD

The HDD's have their own channels effectively and transfer between HDD's was FAR quicker than having both HDD's on the same channel. Also CD copying on the fly took as long as it did to burn the CD.
Far more effective IMHO.

I always try to have a HDD per channel, and the Optical drives put on the least used channels if possible. If not, then my OS HDD on it's own so other HDD transfers do not interrupt my OS Drive. (Lots of large files moving about all the time.)
(Oops - Unintentional rant... The last half of this post was just to give a bit of background behind my view)

[Kumagoro]

I would have thought it would only run at the slowest speed when both devices on the IDE are interoperating between each other. So burning a CD on the same IDE will make it run slower at that time. If you are that bothered about that then have two burners, then then you write stuff from primaray HDD use the secondary burner and when using the secondary HDD use the primary burner and on the fly disc to disc burning should be ok.

[Agent]

Unsure about the amount of chatter the drives will produce but the above comment was true on older chipsets - But, I am 99.9% sure it is not the case for any current chipset. (Do you have proof either way? This has been bugging me for years... )
If you check speeds, look in device manager, copy large files about, benchmark using various apps - There is no difference in speed (UDMA33/66/100/133) of the drive whether the Optical drive is plugged in or not.

Like you said, it does depend on the chipset, but i know that the drives talk even when not "in use". Unplug the drive randomly when its not "in use", and watch your system cry (just did it on my i845 board and it didnt like it one bit, no windows or anything relating to the CD drive was open).

The 33/66/100/133 thing: i must admit, i thought the same as you, but i found a big document on it (well, somone gave me the link anyway that explained all this), which did say otherwise. How true it was, i dont know, but i remember it saying that only one UDMA mode could be used per channel, which would mean only one transfer speed could be used. I wish i could find it so i could post it though
If i get the time, i may well run some of my own benchmarks, as a lot of the stuff does seem to contradict itself at best.

[Captain Fizz]

Found this for DGauld:
This covers Master/Slave/Cable Select:
http://computer.howstuffworks.com/ide4.htm
( First page of article )
But having trouble finding out about the 2 devices on the same controller...
Still looking tho...

And Agent - It WAS your sig I seen the CS strip in. Class!