[Ham-Computers] RE: 5-1/4 FDD Question

[Hsu, Aaron (NBC Universal)]

Short answer is, yes, if your motherboard has a floppy drive controller (and connector), it should recognize a standard PC-style 5.25" floppy drive (360K or 1.2M).

Most all x86 motherboards with a floppy controller should still be able to recognize the IBM standard 5.25" and 3.5" drives (360K, 1.2M, 720K, 1.44M, 2.88M).  However, most people have probably forgotten that the drive needs to be jumpered properly, just like hard drives (SATA an exception).

Floppy drive cables usually have two connectors with a "twist" in the cable between the drive "0" and drive "1" connectors.  The twist was to make it simple to install the drives - set the both drives to ID "1" and the twist "reversed" this selection.  So, if you set the drive ID to "1" and attach the drive to the "end" connector on a 2-drive cable, then the system "sees" the end drive as "0" - therefore, it's the "A:" drive.  So, if your floppy drive cable has the twist, make sure the drive is set to ID "1".  

Word of warning...if you use a 1.2M floppy drive and *write* the the 360K disk, you may not be able to read that disk in a 360K drive anymore.  It's a physical thing...the R/W heads on a 1.2M drive are 1/2 as wide as a 360K drive, so you're not writing data across the "full" width of the track (360K drive has 48 tracks per inch, 1.2M drive has 96 tracks per inch).  So, when you try to read the data in a 360K drive, it's R/W head picks-up the data written by the 1.2M drive along with whatever data was on the rest of the track.  These two combined usually add up to garbage and the 360K drive responds with a sector read error.  By the way, same problem occurs with 100MB/250MB/750MB ZIP disks and drives.

73,

  - Aaron, NN6O


-----Original Message-----
Sent: Monday, May 19, 2008 3:09 PM
Subject: [Ham-Computers] 5-1/4 FDD Question

My olde boss has a 5-1/4 360 KB floppy disk which has some old information on it he wants to recover.  And he like most of us doesn't have a 5-1/4 drive in sight.  I think I have a couple of them still lurking in the attic but does anyone know whether it's likely that a year old Intel board might recognize one of them?  The board is a DG965WH and the machine has a working 3.5 inch drive currently connected to it.  

The reason I ask is that about two system boards ago, I had one that would not recognize a 5-1/4.

If the answer is no, are there any suggestions other than forget it?? :-)

Robert Downs - Houston
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