Subject: Thoughts about wedges
To: None <>
From: Leo Weppelman <>
List: tech-kern
Date: 09/23/1999 16:54:56
From both the proposal mail-archive that was put on the net by Frank and the
discussion following it, I concluded/interpreted the following:

  * The kernel builds the wedge device for the root filesystem. This means
    that at least one of the various partitioning types must be supported
    by the kernel. (Most probably the one 'native' to the port).

  * All disklabel related ioctl's will be moved out of the various drivers
    and will be either:
          - removed (ie. moved to the compat-area) [ is this sdcompat?? ]
          - moved to the wedge driver.

  * The wedge driver is the keeper of the wedge (partition?) info on all disk
    devices. I envision the equivalent of what I called 'in-core disklabel'
    to be present for each device.

  * Recursive partitions are a special case of overlapping paritions.

  * It is a bit unclear when wedge info is destroyed. Must this be done
    explicitely (per disk device, per wedge)? Will media change be detected
    by the wedge driver?

  * We have to figure out a naming sceme. We've just beaten the cXtXdXsX
    scenario to pulp. It looks like 'we' like the driver type based sceme.
    Whatever, I personally think that there must be a link between the
    <driver><instance><partition> (ie. sd1a) and the wedge name.

I mostly wrote the above to clear up my mind a bit. I hope it tells something
useful for others too ;-)