Floppy Drive Controllers And Pin34??

[Beno]

Hey Gang,

I am reading my A+ and this may seem like a silly question but when the author refers to the onboard controller, is he referring to the controller on the motherboard or the controller on the floppy drive itself.

I assume that the controller would be some circutry printed on the back of the controller card. Am I right, or is the controller the device that the floppy drive cable plugs into on the motherboard??

Also in regards to Pin34 of the floppy drive cable, the author stated that this wire is active when a disk is inserted and when a disk is removed!!! This hardly makes sense because if this were the case then the wire would be active the whole time and every time one inserted a new disk into the drive, the same volume contents from the old drive would be showing.
Could someone please clarify that point for me! :-))

Thanks

Beno

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Have a nice day

[geebee76]

Hi Beno,
I believe the controller is on the motherboard in the case of a floppy drive. You have the two connectors on the floppy ribbon cable at one end for drive and A and B and at the other end is the connector for plugging in to the floppy controller on the motherboard. I think that some older floppy drives plugged into a controller on an I/O card, which was, itself plugged into the motherboard.

The floppy drive does have circuitry of its own though, to control the motor, worm drive and heads etc.

As for pin 34, the voltage changes on this when a disk is removed. I am sure the voltage goes low (maybe high, but it definitely changes http://www.PCGuide.com/ubb/smile.gif) telling the controller to read the contents of the new disk and copy it to RAM.

Hope this helps http://www.PCGuide.com/ubb/smile.gif

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[Beno]

Hi geebee76,

So the controller on the motherboard does what??
Does it control data flow into specific areas of the floppy disk, for example cylinder 0, track 2, sector 5 say??

Is this what the motherboard controller does??

I understand that the circuitry on the floppy drive itself controls the mechanics of the drive but just not 100% sure about the mobo floppy drive controller?!

Thanks once again :-)

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Have a nice day

[geebee76]

Hi Beno,

Hit a brick wall with this one but I would guess that the purpose of the controller would be to control the flow of data to and from the drive, along with issuing and accepting signals.
As we have discussed, I think the cicuitry on board the floppy drive must have some form of intelligence to deal with interpreting the signals from the controller and issuing signals to the controller.

As for accessing specific areas of the disc, I would think this would be achieved by a combination of the controller, the on board circuitry and the FAT table.

Is this making sense or am I rambling http://www.PCGuide.com/ubb/eek.gif

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You are making progress if each mistake is a new one!

Sig from Here (http://www.oneliners-and-proverbs.com/)

geebee76@hotmail.com

[andyswork@beci.net]

I think the floppy is based on magnetic-storage concepts, which would make it active all the time because of the magnetic field. As for the controller my understanging is it is in the floppy. To receive control data signals from the computer, and deliver status and data signals back to the computer. This series of connections is called the physical interface. I do this because gee is my friend.

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One day I will be a pro, Thanks Andy

[Paleo Pete]

The floppy controller is on the motherboard. That's the two rows of pins the longer end of the ribbon cable plugs into. Pentium motherboards also have two IDE controllers. Most 486 and earlier boards did not have onboard controllers for either, and expansion cards were used. (Some 486 boards did have onboard controllers, but they were the minority.) Both types of controllers serve the same purpose, to transfer data to and from the floppy drive. They also send signals to the drive to tell it when to attempt to read or write to a disk and where to put the data.

The actual controller is a chip, called the Super I/O Chip (http://www.pcguide.com/ref/mbsys/chip/super.htm). The two rows of pins connect the floppy drive to this chip by way of the ribbon cable.

The mechanical functions of the floppy drive are handled by the circuitry on the drive, commonly a card bolted to the back of the drive. I'm not sure about pin 34, if it was mentioned in any of the books I've read I overlooked or forgot it.

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