Having at last got my IDE (really ATAPI) CDROM working under NetBSD
1.2, here is an attempt to describe in detail what it took in my case.
Hopefully this will help others who are trying to get this working, too.

If there is a canonical FAQ site or other place where this info really
ought to go, please would someone let me know, so we can have it
included there.  Thanks!

Ten steps to an ATAPI CDROM under NetBSD 1.2:

(1) Obtain atapi.tar.gz from ftp://ftp.netbsd.org/pub/NetBSD/arch/i386/
Thanks to <golding@alpha.fdu.edu> for providing me with this URL.
The canonical site for this driver seems to be ftp://ftp.ensta.fr/pub/NetBSD/atapi

(2) Unpack the file somewhere (I used /tmp).

(3) cd /usr ; patch </tmp/diffs-current

(4) Some files get left in /usr that should be elsewhere... maybe I
have poor patching skills, or something??  Anyway, I fixed this by:

    mkdir /usr/src/sys/atapi
    mv ata* acd.c files.atapi /usr/src/sys/atapi
    mv wd* /usr/src/sys/dev/isa

(5) The patch changed the GENERICADP kernel config file; I am using
one with a different name.  So, edit your kernel config file so that
the part concerning IDE controllers reads:

wdc0	at isa? port 0x1f0 irq 14       # ST506, ESDI, and IDE controllers
wdc1	at isa? port 0x170 irq 15       # Make sure this IRQ is explicitly set! JM
wd*	at wdc? drive ?

atapibus* at wdc?                       # Support for ATAPI added.  JM 22 Jan 97
acd* at atapibus?                       # Look for ATAPI CDROM drives.  JM 22 Jan 97

(6) Make sure the CDROM drive is set in master mode, not slave mode.
Many PCs come with the drive set as a slave even when it is the only
device on a secondary EIDE port!  Thanks to <steph@darh.entsa.fr> for
this vital tip!

(7) cd /usr/src/sys/arch/i386/conf ; config FEBCGATE

(use your own config file name in place of my use of FEBCGATE, of
course, here and in (8) below)

(8) cd ../compile/FEBCGATE ; make depend ; make 

(9) mv /netbsd /netbsd.old ; mv netbsd /netbsd

(10) reboot and see if it works.

Jonathan
--
Jonathan Marsden   | Internet: jonathan@xc.org  | Making electronic 
1849 N. Wabash Ave.| Phone: +1 (909) 794 1151   | communications work 
Redlands, CA 92374 | FAX:   +1 (909) 794 3016   | reliably for Christian 
USA                | http://www.xc.org/jonathan | missions worldwide