Re: IDE driver able to hot-swap?

Daniel Engstrom (danne@lillfab.se)
Sun, 2 Aug 1998 13:31:09 +0200 (CEST)


On 1 Aug, brianc@palaver.net wrote:

> I have an ATA Compact Flash Card in my digital camera, and can see it as a
> hard drive on my system via an IDE-enabled Adtron "Solidstate Data Drive."
Which version of the Adtron do you use? There is the SDDA and the SDDB?

The SDDA is a stupid, mechanical adapter that is not electrically
capable of Hot-Swap. Though since its is a purely mechanical adapter
you can use the standard Linux IDE driver with it, provided you have
the card inserted at boot time. Hot insertion/removal of a card in a
SDDA device is equivalent of doing the same with an ISA card.

The SDDB is a more intelligent approach which has hot-swap capable logic
on-board, you'll notice a Xilinx 3030 SRAM based FPGA on the device.
Also note the absence of any FPGA program ROM, that's right the FPGA in
the SDDB must be programmed by the Adtron supplied DOS/95/NT drivers. A
Adtron SDDB can not be used with Linux until Adtron or somebody else
writes a driver specific to the SDDB for Linux.

> The gist of my question is "why can't I hot-swap cards in and out of this
> drive using the Linux IDE driver." I am told that hotswapping can be done
> under M$ Win/NT.
Incase of the SDDA i doubt it. Atleast you should never rinsert/remove
a card in a SDDA under power.

> As long as I power down the computer, boot it up with the card in the drive,
> and leave it in there, it works just fine, looking like a 20MB DOS-formatted
> disk.
As one could expect from a card in a SDDA.

> If I unmount it though, or remove the card from the drive and then re-insert
> it, I haven't figured out any way to subsequently use the card.

I'd say you should be happy you didn't break anything in doing that.

> If the IDE driver *should* be able to do this, I'd sure appreciate knowing
> how.
It should not.

If you want a hot-swap solution that works with Linux I think the
Adtron SDDS is what you need. It connects to a scsi bus and look like a
removable-media device.

/Daniel

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