ATA100 HD on a UDMA/33 mobo controller

[velocity]

can an ata100 HD be made to work on an onboard controller thats only udma/33 - the cable for the ata100 hd does not fit onto the mobo controller and the standard ide cable from the ata100 hd to the mobo does not allow for detect of the HD - any help?

thanks.

P.S. - i know I could get an ata100 controller card or buy a mobo with ata100 support but i have to budget and do things in steps - I was hoping the ata100 hd would be backward compatible for the time being.

[Fingers]

ATA/100 is completely backward compatible with ATA/33/66 motherboards and controllers. Newer ATA/66/100 drives will automatically adjust their speed to whatever the IDE controller is capable of. ATA/100 uses exactly the same 40 pin connector as ATA/33 and ATA/66.

I'm not sure why the IDE cable wouldn't fit onto the onboard controller because ATA33, ATA66, and ATA100 use exactly the same connectors. The only thing different about ATA66/100 cables is the addition of 40 extra ground wires, (1 for each of the original 40 conductors) but the connector remains unchanged.

Are you certain that you are trying to connect the drive to one of the 2 40-pin IDE connectors and not the 34-pin floppy connector?

[velocity]

hi! ....yes I am connecting to the 40pin HD (or trying to) ...not the floppy - the problem is the ata100 cable has one hole blocked or covered on the connectors end. When attempting to connect it to the ata33 40pin controller on the mobo this pin is there and so the cable connector cannot be seated in. Can I carefully drill this covered hole out so that all the pins will slide into the cable connector?

[Bear]

You can usually remove that little piece of plastic that is blocking the hole, I use a straight pin to pry it out. It has worked fine for me.

[Fingers]

Well, I learned something new today. http://sysopt.earthweb.com/forum/wink.gif I was aware that in order for ATA/66 to work, pin 34 had to be an open circuit, but I was unaware that manufacturers had made any additional changes to the connector for ATA/100.


Here's a quote from Seagates FAQ page. (http://www.seagate.com/support/kb/disc/ultra_ata_66.html)
Ultra ATA/66 technology is defined such that the PC and the hard drive can both detect the presence of the required 80-conductor cable. The system board must have a special capacitor on pin 34 to detect the cable. The cable must have a notch cut in line 34 to correctly detect an Ultra ATA/66 device.

A quick check reveals that ATA/100 cables require a higher standard of quality than a standard 40-pin, 80-conductor ATA/66 cable. I'm going to assume that this "tab" on the cable is to prevent the use of an otherwise identical ATA/66 cables on an ATA/100 system.

You might want to review this article from Quantum on ATA/100.
Ultra ATA System Requirements (http://www.quantum.com/app_notes/app_note_ata_ultra66.htm)