Are there still cd(4) changers?

[Kenneth D. Merry]

On Fri, Apr 04, 2014 at 14:50:39 +0300, Alexander Motin wrote:
> Hi.
> 
> Does anybody still use CD changer supported by cd(4) driver in FreeBSD, 
> not ch(4)? Those changers have single drive, but report multiple LUNs 
> with one LUN per CD slot.
> 
> One device like I have in my table is 17 year old. All devices I can 
> find with Google or eBay are CD, not even DVD, and are parallel ATA or 
> parallel SCSI. Is there anything relevant still on market?

I have one, but like yours, it's very old.  (It's one of the ones I used
when I wrote the changer code in the late 90's.)

> I am asking this because code supporting that hardware in FreeBSD is 
> heavily broken in head and stable/10 branches for several months now, 
> and fix seems to be non-trivial. So my question is: does it worth 
> bothering with rewrite, or we can just drop ~20KB of unused and quite 
> complicated code? Dropping code does not mean those devices will be 
> unusable, but only that _simultaneous_ access to different LUNs will 
> become much slower due to inefficient scheduling of disk loads/unloads.

I think it is fine to take it out.  Let's see if anyone who is using one
actually speaks up, but I would imagine that very few people are using
them.

Removing the code will simplify the driver, and it is becoming more
difficult to find the hardware to even run one of those devices.

I doubt we'll see anyone attempt to make one of those again.  It'll
probably remain like it is now -- either single disk devices, or large
optical changers that would use ch(4) to do the changing.

Ken
-- 
Kenneth Merry
ken at FreeBSD.ORG