Re: IDE and hot-swap disk caddies

John Summerfield (
Wed, 27 Mar 2002 06:53:47 +0800

> At the interface level, there is some support.
> Look at hdparm's -b option to tristate the bus.

There is no mention of -b in hdparm's help screen, and in the man page
it's only mentioned in the description of -L.

Is there a newer version of hdparm I need?

> But that's the whole bus. If the controller implements

IDE1? That's okay for me, I can control the hardware configuration to
that extent. If the other device is a CD reader, I'm not going to
corrupt anything. If necessary, I'll make sure it's unmounted.

> master/slave on one cable, you're hosed, electrically.
> It's the whole interface. 95% of controlers are like this.
> Intel's PIIX can do master/slave on separate ports, but
> then you loose one bus. Laptops with bays also do things
> like this, but that's special hardware, hard to get programming
> specs for.
> I think if you add the drive *after* boot, it doesn't
> have the benefit of the BIOS setting up PIO/UDMA modes,
> so I would try the hdparm -X speed settings also.

At present the system hangs if I add a master when the primary's
present, before I get to do anything.

I've not tried adding a slave to an existing master.

As to the BIOS settings, I only configure drives required for booting.
I've been doing that for years, before I ever used Linux, when I
discovered that OS/2 wasn't paying attention to them. (A good thing in
the case of OS/2 as the instructions for one of my drives gave the
wrong geometry;-().

> Jeremy
> ----- Original Message -----
> From: "John Summerfield" <>
> Sent: Monday, March 25, 2002 3:16 PM
> Subject: Re: IDE and hot-swap disk caddies
> > > > The device is hot-swap capable and has a switch (others have a key)
> > > > that locks the drive in and powers it up; in the other position the
> > > > drive is powered down and can be removed.
> > >
> > > Linux doesn't support IDE hot swap at the drive level. Its basically
> > > waiting people to want it enough to either fund it or go write the code
> > >
> >
> > What needs to be done? How extensive is the surgery needed?

John Summerfield

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