CDRW on primary channel with HDD

I’ve got a 60gb Maxtor HDD UDMA-133 fitted on the primary master channel,if i fit a CDRW onto the primary slave will it slow my HDD down by defaulting it to UDMA-33 (or whatever a CDRW is)?

My Secondary channel already has 2 drives fitted.

All modern IDE controllers are capable of operating two drives at different speeds on the same IDE cable. That isn’t an issue.

However, there is a potential performance issue when you put two IDE drives on the same cable. Unlike SCSI, IDE can’t multi-task I/O operations between two drives on the same cable. This means that whilst the computer is waiting for a transfer to or from the optical drive you’re proposing, your hard disk is momentarily inaccessible. This is one reason why SATA opts for the far simpler one drive per cable setup.

You may have problems trying to burn data on an IDE hard disk to a writer on the same IDE channel.

If you want to fit another optical drive to your system, the best bet is probably to move your hard disk to an IDE controller card, and use the two IDE channels on the motherboard for the optical drives. There are cards available now that have two SATA ports and a conventional IDE (parallel ATA) port - if you used one of those, you’d be able to fit SATA drives in the future without buying another controller.

David

Thanks for the great info.
At the moment i’ve got my dvdrw on the primary master and the dvdrom on the primary slave,when i back up dvd’s i always create an image to the hdd so i’m not concerned about ‘on the fly’ copying.
However i wanted the cdrw on the secondary slave so i could use this for ‘on the fly’ copying of cd’s from my dvdrom drive.
I don’t want to burn my dvdrw out just for cd copying,also my dvdrw doesn’t copy some protected games.

You may have problems trying to burn data on an IDE hard disk to a writer on the same IDE channel

Not really. Transferring data from one drive to another is one operation, not 2. Virtutally all IDE controllers made in the past 3 years are more than capable of doing on-the-fly transfers on the same IDE channel, in fact some may even be faster that way.

Originally posted by rdgrimes
Virtutally all IDE controllers made in the past 3 years are more than capable of doing on-the-fly transfers on the same IDE channel, in fact some may even be faster that way.

Well, I don’t deny the real world experience, but I can’t make any sense of this from a technical point of view.

IDE has no disconnect system, unlike SCSI. This means that when an I/O request is pending with one device on the IDE channel, the other device is blocked. If you have a writer and a hard disk on the same channel and the writer decides to go away for 500ms (maybe whilst writing a lead-out?), your hard disk is inaccessible for that period.

This article on the Feurio web site gives another explanation of this.

With SCSI the situation is different - the devices can disconnect from the SCSI bus whilst the request is pending, then the drive can reassert the bus when it’s ready to complete the transaction.

David

its getting a bit too technical for me now,basically DavidW would you advise against me putting a cdrw as slave to the hdd?

I’d stick by my original advice, in recommending that you consider fitting an IDE controller card (possibly one with both an IDE channel and a couple of SATA ports, so that you can fit SATA drives in the future), and move your hard disk to that.

There are at least theoretical performance issues with putting a hard disk and a writer on the same IDE channel.

However, if you want to try a writer on the same IDE channel as your hard disk, why not set up such a system? You may find the that the performance issues are purely theoretical and you don’t get any problems in “real life”. rdgrimes indicates it has worked fine in his experience.

If you find it really doesn’t work out, then you can always opt for a controller card later.

One thing you didn’t do was identify the two drives on your secondary IDE channel; it may be that it makes more sense to shuffle those around.

David

I did it once. It sucked. Don’t put any optical drives on the same IDE channel as a hard drive. Not much to it. still need more space? get a pci controller card. If u can live with the speed hit, it is cheaper to put them together, but its REALLY a bummer.

thanks again for the help.
On the secondary master i have a dvdrw drive
On the secondary slave i have a dvdrom drive

To be honest I didn’t really want to go to any extra expense (i’ve only just brought the dvdrw)so i don’t think i’ll be getting an IDE controller card.
The cdrw drive would only be used occaisionally when i’m backing up cd’s because I don’t want to burn my dvdrw out just for cd copying,also my dvdrw doesn’t copy some protected games so it would have been ideal for these odd few games.
If the hdd is going to suffer then i’ll get by without the cdrw,i can’t try it at the moment because the IDE cable isn’t long enough anyway.
I would need to get one to try it and i’m not sure which one i’d need ie: ata 133,ata100 etc to run both hdd/cdrw on the same channel.
The only thing i know is that the one fitted is a 40 pin 80 cable one.

If u really want to get the cdrw goin as well, firewire is always an option. usb2 is as well, but I don’t like it.

The cable is then an added problem. Whilst cables longer than 18 inches (45cm) are available, they break the IDE specification.

For what it’s worth my personal IDE rules are that hard disks go on a channel by themselves, or, at worst, with another hard disk. I do put two optical drives on a channel if I’m out of channels.

My current box has the following drive setup:

LSILogic 1020 U320 SCSI controller:

ID 0: Seagate ST336753LW
36GB Cheetah 15K.3 - a 15000rpm U320 SCSI disk
Boot, OS, applications, small swap file

ID 1: Seagate ST336753LW
36GB Cheetah 15K.3 - a 15000rpm U320 SCSI disk
Main swap file, main data

ID 4: Seagate (Certance) STD2401LW DDS-4 U2W tape drive

Intel ICH4 IDE controller:

Primary master: Seagate ST3160023A
160GB Barracuda 7200.7plus - a 7200rpm IDE disk
Backups to disk, scratch space

Secondary master: Lite On LTD163 DVD-ROM

Secondary slave: NEC ND-2500A DVD±RW

I’m lucky - because three of the six drives are SCSI I don’t have any problems with trying to deal with a limited number of IDE channels. On the other hand, I’m short of PCI slots. I’ve got several PCI-X slots (into which I only want to put PCI-X cards so as not to slow down other PCI-X hardware) - but PCI-X IDE controllers are still expensive. Highpoint do a rather nice 8 port PCI-X SATA RAID card - but that’s overkill for my application!

David