2-channel IDE motherboards (like P4B266) and CDROM integ

Discussion in 'Computing' started by DizzyFingers, Mar 7, 2002.

  1. DizzyFingers

    DizzyFingers Guest

    I am a new user here, so I want to start out by thanking some of the heavy hitters here for all of the valuable info! I have done tons of research..in addition to this board...and have one last stumbling block...

    In talking to one of the more informed techies I know..I recently discovered that if you put a CD-ROM or RW CD-ROM on the same channel as a UDMA 100(or 133) Hard Drive, the bus speed on the IDE channel is clamped to the slowest device...

    In other words, it is doing you no good to buy that expensive HD if you are putting it on the same IDE channel as a CD-ROM.

    This issue is bothering me because I was planning on buying the Asus P4B266 with 2 IDE (standard) channels, but I have seen a big emphasis on separating your OS, data, and applications on seperate physical drives. In thinking about the limitation, say I was to have a smaller older drive that I want to use for my OS..I could use IDE0 for the smaller drive and CD-ROM, but I am then only left with one channel IDE1 for the 2 big drives I was going to buy 1 for data and one for apps...having these on the same IDE channel is going to defeat the purpose trying to separate them in the first place because they will have to take turns on the IDE1 bus.

    I can think of a few workarounds, but hope that someone (maybe Opus) can come to the rescue with a solution. The only thing I see as an option would be to spend a bunch of $$$ on a CD-ROM that uses firewire or some other type of connection than IDE...


  2. Opus2000

    Opus2000 Well-Known Member

    Apr 7, 2001
    Hey Dizzy
    I think you've misunderstood some of the posts here or read some bad information somewhere...basically you want to keep your OS and Applications all on one drive..the on on the primary controller. See, the registry maps all the software and OS installs and when you have the OS and Apps on different drives you start getting into path nightmares in the registry....keep it clean..install Apps and OS on the main primary drive..
    now as far as the hard drive and CDROM on the same IDE cable...it's fine! Trust me!! The speed that you need is really from the Audio drive! That's where the major bottleknecking comes in! So, when you start getting bogged down it's due to your audio data drive not getting the pull it needs...to solve this get yourself a HiPoint ATA 133 Raid controller! Simple as that!! That's what Jetoney did and it's awesome!! Fast, responsive and a clean registry!!
  3. Prof.Sound

    Prof.Sound Guest

    I understand what Opus is saying, however, in my experience, it is true that your channel will slow down to the slowest device, and I'm not sure he's agreeing or disagreeing?

    The slow down may or may not be important, it depends upon how you will use the system? For example, if you think about it, just because you put a fast device on the channel, its not going to make the slower device any faster. So if you are doing a read/write to the slower drive, it's only going to move data so fast. If you move data on the same channel to and from 2 devices on the same channel, something has to wait while data flows. Hence why Apps on one and Audio on the other. Audio has to stream uninterupted to gain maximum performance..

    The Promise Raid card is a great solution, and its really the major benefit of the RAID MB's out there. you get 2 more channels and then the card handles it.

    I can't help but wonder, if you are to buy 2 new drives, why keep the old slower one? All you need is 2 good drives anyway, why complicate the issue? Ditch that old one and take advantage of that new MB and drives you're buying.

    Put the Apps and CD on channel 1, and the Audio HD on channel 2. If you get the RAID MB or Card, then you're golden.
  4. DizzyFingers

    DizzyFingers Guest

    Thanks for the feedback!

    just to clarify my previous post. I was considering keepng the old drive if the newer one was not going to give me a performance increase..I kind of rambled on about buying 2 drives when I was actually questioning whether or not I needed the 2nd big new drive.

    Opus, I talked again with my techie friend and he agreed with you..he clarified that he runs SCSI so he can have his apps, os, and data drives on different physical drives. He has several machines and he actually has his apps seperated so he can hot swap if need be.

    But, I think there is something to learn from this post & that is the fact that your IDE bus will only run as fast as your slowest device on that bus. So, if you can save 20 or 30 bucks on a 5400 RPM drive over a 7200 or get a larger 5400 for the same price & you know this drive will be sharing an IDE channel with a CD-ROM device...do it...also, the new UDMA 133 drive spec is a complete joke. Keep in mind that this rating is based off of maximum burst data rate (kind of like buying speakers or audio equipment that is rated 300 Watts MAX output, but that runs at only 50 Watts RMS). When readingwriting data Burst data transfer rates rarely go above 50, this is why a big performance increase was seen from the 33's to the 66's, but from the 66's to the 100's there is very little performance increase...Take the conceprt a step further and think about 100 to 133..sorry, but you are not going to go there in the first place!

    As a result, Maxtor was the first one whose Marketing dept. determined that this could be a great "marketing" ploy and decided to invest R&D $$$ toward this standard. This is why other drive manufacturers have been slow to adopt the standard and there remains a question as to whether or not they will... instead these maufacturers are focusing their R & D efforts on implementing a "fast" serial method of accessing Hard Drives...most of the limitations they are running into are a result of the parrallel nature of the 40 or so pin IDE cable. Even though you are going Serial they are getting much faster results. So, before too long you will not be seeing the old IDE pin-outs on MotherBoards. Keep this in mind when recommending a 133 IDE controller...the 133 sounds great, but hopefully after reading this post you will understand what it is really bringing to the table..

    Thanks again for the Feedback!

  5. quixzika

    quixzika Guest

    Just thought I'd chime in with my ignorance.
    Does this mean that if the OS and Progs HD is on the same IDE channel as the CDRom, it will nott effect the speed of the DATA HD on the second IDE channel? Or is this where you MUST have a RAID controller to loop around the IDE channels?

    - I am correct in thinking the 2 IDE channels are not connected?
    - So the OS/Progs HD can be a 7200 rpm ATA 100 or 133 and it doesn't really matter?

    My learning is BREEDING apparent ignorance!


  6. knightfly

    knightfly Active Member

    Jan 18, 2002
    Now you're getting warm - This is why the system I've been designing and researching for the last few months will have NOTHING BUT hard drives on ANY of the four IDE channels (two normal, two raid channels) That way, there is nothing slowing down any other device on the IDE chain(s) -

    And yeah, each IDE channel utilizes its own driver chip, so they are independent devices, even using a separate IRQ.

    I will be utilizing the firewire interface for all optical drives, and only the optical drives will be inside the studio control room. The first IDE channel will be a boot/apps drive with a second "scratch pad" drive, the second IDE channel will go to two DataPort plug-ins for customer removable drives, and the two "raid" channels will connect to 4 internal drives, which may or may not be set up as a raid depending on my benchmark results. All drives will be 80 or 100 GB 7200 RPM, and since the computer will be outside the control room I can have as many fans as it takes to keep all those drives cool. This is one reason it has taken so long to finalize components - I don't want a bunch of PCI slots taken up with stuff I need and can get as part of the MoBo.

    However, I've found that not all embedded raid controllers are created equal, and not just whether they are ATA100 or ATA133. Of the two most prevalent, the HiPoint allows the raid to operate as 0, 1, or 0+1. The Promise embedded raid only allows 0 or 1. Both embedded raids allow using the two IDE connectors as just two more normal IDE channels. The separate PCI cards from both Promise and HiPoint allow all 3 modes mentioned above.

    From everything I've read, NONE of which includes my own personal testing, a slower device on the same IDE channel with a faster one supposedly slows the faster one down. If this is true, and you are setting up an audio machine, then it would follow that it is better to have programs load slower rather than have the main reason for a dedicated audio recording drive eliminated by tying an anchor around its private parts and yelling, "go, you bastard, go!!!" If putting a CD-Rom drive on the same channel with the boot drive DOESN't slow it down, then you've lost nothing, and you're still better off with the dedicated audio drive on its own channel. The ideal, even for non-maniacs, would be a raid MoBo with only one device on each channel. This brings up another limitation to be worked around: From what I've read so far, most if not all raid MoBo's don't work with CD-Rom devices on the raid channels - no biggie, just put the boot/apps drive on the first IDE, the optical drive(s) on the second IDE, and use the two raid channels for one audio drive each, which leaves expansion room for three more hard drives if/when necessary; one more on the channel with the boot drive (a good reason for a fast boot drive, so it won't slow down a second drive)and one more drive on each of the two raid channels. Since I personally am getting tired of ^#$%ing with computers and want to make some music for a change, I intend to max out the system in the first place, and never open the freakin' case again til it falls apart! Now we be jammin'... Steve
  7. Jon Best

    Jon Best Active Member

    Mar 18, 2001
    I may be wrong here, but I think that 'slowing down to the speed of the slowest drive' just means what standard the drive uses, i.e., if you have an ATA33 drive on a channel with an ATA66 drive, the whole shebang is going to run at ATA33 speeds. Same as with SCSI- if you put a SCSI2 drive on an Ultra160 controller with an U160 drive, all three will run at the much slower SCSI2 speed. However, if you stick a (slower) 7200 rpm U160 drive on a chain with a (faster) U160 15,000 rpm drive, the faster drive isn't going to slow down.

    I'd say, put your CDRW on the primary controller with your OS/app drive, and your CDROM on the secondary controller as slave with your audio drive, and you'll be fine- the CDROM isn't going to slow down your audio drive unless it's actually doing something, and using up bandwidth.
  8. Opus2000

    Opus2000 Well-Known Member

    Apr 7, 2001
    Personally I dont think that it's going to decrease your performance to a point where you will notice anything. That's why I always put the hard drive on the middle connector of the IDE cable..it's closest to the motherboard and so it doesnt need to buffer through the CDROM before getting to the mainboard controller. That's why we reccomend putting your audio drive on a SCSI bus or getting a ATA100 or 133 controller card.
    I understand the issue of wanting to make sure the system runs efficiently but to be honest at this point it seems like we're beating a dead horse..fun as it may be :roll:
    Of all the systems I've built and configured never once was there a question about the speed of the drives actually being bogged down. performance will always be the same...unless of course you use ATA33 drives!!
  9. DizzyFingers

    DizzyFingers Guest


    I don't want to appear to be ganging up one you, but my experience has been if you put the best minds together and have them dual it out you learn the most...the techie friend I referred to in my 1st post had a bit of feedback on your response... this guy lives for bits.. hardware or software, so I have always respected his input..

    so lets beat that horse a few more times...


    The information about putting the drive in the middle of the cable is questionable (this would cause reflections in the signals). Your best bet is to place it on the end, since the CDROM will not be the device buffering anything. As long as it is quite(inactive) your bus speed will match the hard drive, otherwise it will be the speed of the CDROM.

    The person below mentions that SCSI would would be good as well. There is a reason that I run only SCSI devices on my "home" system which serves six other computers as well as hosting other devices (it's a 233 pentium box). But in your case, if your machine is a single user then SCSI is too expensive (unless you need the hardware error correction and RAID and the ability to run 365.25 days a year with no down time). A separate ATA controller for your drives is a good option too, a lot less money than SCSI. Mind you, a SCSI166 will let you transfer data at 166 million bits/second (Mp/s), per device, where a typical ATA (non-ultra) sits at about eight Mp/s.

    This is just some additional information that you may find interesting about how to connect your HDD and CDROM to a single IDE cable.

    Integrated Drive Electronics (IDE) interface can support up to two devices. Most mainboards today come with two IDE interfaces, a primary and a secondary. This allows support for up to four IDE devices. Because the IDE controller is integrated within the drive, there is no overall controller to decide which device is currently communicating with the computer. This does not cause any problems as long as each device is on a separate interface. If you decide to add a second drive on the same cable then you have to think about location and addressing.

    IDE uses a special configuration called master and slave that allows for two drives on the same cable. This lets one drive's controller tell the other drives controller when it can transfer data to or from the computer. What happens is the slave drive makes a request to the master drive, which checks to see if it is currently communicating with the computer. If the master drive is idle, it tells the slave drive to go ahead. If the master drive is communicating with the computer, it tells the slave drive to wait and then informs it when it is done.

    The computer determines if there is a second (slave) drive attached by sensing pin 39 on the connector. Pin 39 carries a special signal, called Drive Active/Slave Present (DASP), that checks to see if a slave drive is present.

    Although it will work in either position, it is recommended that the master drive is attached to the connector at the very end of the IDE ribbon cable. Then, a jumper on the back of the drive next to the IDE connector must be set in the correct position to identify the drive as the master drive. The slave drive must have either the master jumper removed or a special slave jumper set, depending on the drive. Also, the slave drive is attached to the connector near the middle of the IDE ribbon cable. Each drive's controller board looks at the jumper setting to determine whether it is a slave or a master. This tells them how to perform. Every drive is capable of being either slave or master when you receive it from the manufacturer. If only one drive is installed, it should always be the master drive.

    Most drives can use Cable Select (CS) if used with the correct type of IDE cable. This allows the drives to be auto configured as master or slave. The jumper on each drive is set to the CS option. The cable itself determines which device will be the master by using pin 28 to connect to the master drive connector. When your computer is powered up, the IDE interface sends a signal along the wire for pin 28. Only the drive attached to the master connector receives the signal. That drive then configures itself as the master drive. Since the other drive received no signal, it defaults to the slave drive.

    Speed is another issue. Remember anything about PIO1, 2, 3, 4, and 5? Your bus is as fast as your slowest device, get Ultra DMA devices and the fast CDROM you can buy (56x - but check the transfer speed - not burst speed).

    Nuff said, you decide...


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