Date: Sat, 13 Sep 1997 10:11:32 +0930 From: Greg Lehey <grog@lemis.com> To: Robert Clark <ROBERTC@PII.COM> Cc: questions@FreeBSD.ORG Subject: Re: Floppy Trouble / Cable Select. Message-ID: <19970913101132.23596@lemis.com> In-Reply-To: <s4190852.036@pii.com>; from Robert Clark on Fri, Sep 12, 1997 at 09:05:16AM -0700 References: <s4190852.036@pii.com>
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On Fri, Sep 12, 1997 at 09:05:16AM -0700, Robert Clark wrote: > Scenario: > > You have two floppy drives in your PC. For some reason, you would like > to swap A: & B:. Your BIOS won't do it. > > You reach into the case, and move both drive select jumpers from 0 to 1. > (Or is it the opposite?) No. From 1 to 2. > Now drives A: & B: are swapped. The controller can address four units, 0 to 3. It outputs the drive number in binary on two drive select lines. You all know what a floppy cable looks like: it's a kludge, they've torn the flat cable apart and swapped the drive select lines. This means that you don't need to set the jumpers on the floppy itself. They're both set to 1. The system addresses /dev/fd1 as unit 1 and /dev/fd0 as unit 2. The swap in the cable swaps the two address lines, so the second floppy responds to address line 1 (the '2' bit) instead of address line 0 (the '1') bit. > Problem: Things get weird. Some systems don't like this arrangement. They can't tell. It's the same as swapping the cables. Of course, it's important to change both drives. > Would this affect FreeBSD? No. But why would you want to use floppies with FreeBSD? Greg
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