Detecting 'floppy' like umass devices
ticso at cicely12.cicely.de
Wed Apr 21 02:54:54 PDT 2004
On Wed, Apr 21, 2004 at 01:29:29PM +0930, Daniel O'Connor wrote:
> On Tue, 20 Apr 2004 18:28, Bernd Walter wrote:
> > > I am wondering if there is any way of telling if a given umass device is
> > > a floppy drive (or wants to look like one) - eg I have a USB FDD which
> > > I imagine should fall into the same basket.
> > What do do you mean with "wants to look like one".
> > In which way does a floppy look different from other direct access
> > drives?
> > They all read and store direct access data.
> Partially to handle things like fdformat, and density selection, but also from
> a user point of view, ie it would be nice if it appeared as /dev/fdX.
OK - density has to be configured raw.
Do USB floppies support different formats anyway?
> IMHO it's not obvious (and dangerous) to tell mtools that a: = /dev/da0 but
> that's what I have to do if I want to use my USB FDD with it.
That's what I have to face with my MO drives since years.
And it's the same story that you can overwrite the wrong streamer
The real point that is missing here is working hardwiring of USB mass
Plus I never liked ad0 vs. da0 problematic - typos can me made too
But that's the way is is: You are root.
> > > I note that you get wacky values from fdisk when you try and read
> > > partition table from them too..
> > >
> > > On another note my USB floppy drive does 2k/sec in FreeBSD :(
> > Sound like another instance of msdosfs does no clustering and drive
> > is too stupid to get speed without.
> > IIRC there were some work on this point, but I don't now the state.
> > Check the speed with dd and different blocksizes.
> This IS with dd :)
> I did a few tests..
> Block Size | Speed
> 0.5k | 2.2k/sec
> 1 k | 4.4k/sec
> 2 k | 8.0k/sec
> 4 k | 12.6k/sec
> 8 k | 17.7k/sec
> 16 k | 21.8k/sec
> 32 k | 23.9k/sec
> 64 k | 26.2k/sec
> Bleh :(
Yes that drive would massivly win from IO clustering.
UFS should work fine, but msdosfs...
B.Walter BWCT http://www.bwct.de
bernd at bwct.de info at bwct.de
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