How an IRQ setting impacted a floppy drive

Solutions to inaccessible floppy drive

A recent Technical Q&A discussion on Windows 98 SE's inability to recognize a floppy disk drive (FDD) illustrates how brainstorming, research, and peer discussions are all important ways of resolving the problems that plague support techs. The member who posted the question, Mike Drynan, actually solved the conflict within a day of posting it, but the discussion didn't stop there. Mike's post prompted more than a dozen TechRepublic member responses outlining possible fixes and causes.

The problem: An inaccessible floppy drive
Mike's problem: His Win98SE PC sees the floppy drive but cannot access it. Apparently, Windows thinks the drive isn't ready. He can boot in safe mode and the floppy drive works fine, but in normal Windows mode, attempting to access the floppy drive locks up the PC.

In the course of looking for a remedy, Mike:
  • Removed a modem that wasn't listed in devices.
  • Removed the floppy controller and drive in both safe and normal modes (each done separately) and let the system find the new hardware.
  • Booted in DOS (drive worked fine).
  • Restarted Windows into DOS mode (drive produced read error).
  • Ran Windows update.
  • Ran Norton's Win Doctor.
  • Per Microsoft's Knowledge Base article Q131690, clicked the Disable In This Hardware Profile check box, and checked Config.sys and Autoexec.bat for conflicting files.
  • Stopped all processes in Task Manager except Explorer and Systray.
  • Reloaded Win98SE.
  • Swapped out the floppy drive and cable with new ones.
  • Checked the BIOS settings, and allowed another tech to do the same.

Solution then problem: An upside-down discussion
Remember, this problem was solved in a relatively short amount of time. To everyone's surprise, an add-on card, used to provide a secondary parallel port to the PC, was to blame. Mike, who was suspicious of this piece of hardware, checked several times to verify that no conflicts in system resources existed. Because none were reported, he didn't see the card as the problem but decided to remove it out of desperation. The add-on card ended up being the culprit—as soon as the card was pulled, the floppy drive began to function normally in Windows.

In this case, an IRQ conflict was to blame. Members TheChas and Maxwell Edison both commented on this interesting turn of events. TheChas wrote, "While Windows did not report a resource conflict (IRQ sharing), I suspect that if you check things out at the DOS level, the parallel port card was using an I/O address that was required for the FDD controller. If possible, verify the default I/O addressing that the motherboard uses. Then, compare that to the I/O settings on the port card. It is possible that installing the parallel port card in a different slot will eliminate the problem."

Maxwell Edison added this IRQ advice. "Add-on I/O cards, controller cards, parallel/serial cards, etc., often have jumpers or dip switches that set IRQ (and other) settings manually. I suspect this is the case. You could verify this, set the card to avoid conflicts, and reinstall it. In addition, the manufacturer of the card most likely has an online manual you could reference for such information."

These are two great reminders about IRQ settings and the conflicts that can occur. But as any tech knows, floppy drive problems can occur for a variety of other reasons. Aside from a physical repair, TechRepublic members pointed out several other fixes for floppy drive problems.

BIOS setting changes
In Award BIOS (and maybe others) there is an option, Report No Floppy Drive For Win 95—Yes/No. If this is set to Yes, it produces the exact problem Mike was having. Yes is the default setting for many motherboards and applies to other versions of Windows also, so the option is worth a look in your troubleshooting process. (Electricdragon provided this tip.)

Be sure the standard BIOS setup is set correctly for your floppy drive (most are 3.5 in., 1.44 MB). If you have more than one floppy drive, check to see if you have floppy drive swapping enabled in the CMOS. (Maxwell Edison provided this suggestion.)

A conflicting/bad driver
Sometimes Windows thinks it can share a resource when it really can't, and no caution flags will appear in Device Manager. But these invisible problems can be solved by opening Device Manager, selecting the floppy drive in question, writing down the resources it's using, and then checking it against the rest of the components. If any conflicts appear and the floppy drive is using the correct resources, change the settings for the conflicting device to DMA=2 I/O=03F2-03F5 IRQ=6. (Electricdragon suggested this solution.)

Several Windows 98 systems will not access the floppy drive until the appropriate motherboard/chipset drivers are installed. This is a problem with the Alladdin 5 chipset from ALI. If you need help identifying the motherboard or chipset, check out the tools at either or Wim's BIOS Page. (TheChas provided this tip.)

Hsflop.pdr file
Some people have reported that renaming or removing the Hsflop.pdr file from their Windows\system\iosubsys folder has solved the problem of Windows 98 not being able to access a floppy drive when DOS can. After changing the name or deleting the file, reboot and try the drive. Sometimes the drive will work without the file, and sometimes you will need to replace it with a new copy. You can restore the file using the system file checker, the Sfc.exe command. (DrBob and DKlippert suggested this solution.)

Keep the discussion alive
This floppy drive error produced quite a lively discussion even after the solution was identified. Thanks to Mike Drynan for posting his quandary and to all the TechRepublic members who offered help, but don't let the dialogue end here. How would you have handled the situation? Did the IRQ conflict light bulb go off in your head? Post a comment to this article or visit the Technical Q&A to tell the world about your most recent support stumper.

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