Re: Compat symlinks for /dev/acd0?

Craig Rodrigues wrote:
> When the ATA_CAM option is enabled in the kernel, we create
> compatibility symlinks for /dev/ada devices, such as: /dev/ad8s1_at_ -> ada0s1
> 
> We don't do this for ATAPI CD-ROM devices.
> 
> Any reason *not* to do this for ATAPI CD-ROM devices?  i.e.  /dev/cd0 -> acd0

I see no strong reason why it should not be done, but either I see no
much reasons to do it:
1. acdX (same as other ATAPI devices) had no static IDs, that are
difficult to map manually in case of adX;
2. in opposite to 1, it is not reliable to automatically predict that
cdX always maps to acdX when there is more then one CD, especially if
some of them are not ATA; I really wouldn't like to track second set of
device unit numbers, existing now quirks are very noninvasive;
3. half of CD operation is writing and linking to the device with
different API won't help it;

> It's a minor thing, but will definitely hit people who have /dev/acd0
> in /etc/fstab when they upgrade to 9.0.

adX->adaY change is a major hit for majority of people because their
systems just won't boot without these links. Same time I have doubt that
many people are automatically mount their CDs on boot from the fstab and
many system won't boot even without CDs at all.

> People can read UPDATING and the release notes, but if we can do this
> minor thing, it might make migration easier.

At some moment user still have to read UPDATING or release notes and
update fstab.

It is quite easy to create cdX to acdX symlinks. I've made a patch in
five minutes. Is there anybody else who thinks I should commit it?

-- 
Alexander Motin