On 04/05/2019 21:36, Dave Wade via cctalk wrote:
  Paul,
 VAX CD-ROMS generally are not ISO. ISO implies the ISO9660 file system, but many VAX CD
ROMS are in native VMS Files-11 format.
 Some Windows utilities don't handle these so you need third party software to create
an image of these CD's.
 Generally it has a .iso extension but as the content is not ISO9660 you can't mount
it on Windows or Linux.
 There a couple of utilities that will convert arbitrary files to image files.
 I tend to use CD Burner XP
 
https://cdburnerxp.se/en/download
 but you need to click "More download options" and use the "without install
core" versions....
 Dave 
VMS CDs are indeed in ODS-2 format. Windows certainly won't mount them
but many of the imaging utilities I used to
use under windows would happily produce a valid image that could then be
burnt to CD-R and used in a VAX (so I'm
fairly sure they did a proper, correct image copy). Nero and CDburnerXP
come to mind.
FWIW it is possible to produce a CD that can be mounted as ISO9660 on
(say) Windows but also presents the same data
as an ODS-2 filesystem on VAX (or Alpha). I even built one or two such
images back in the day.
Antonio
--
Antonio Carlini
antonio at 
acarlini.com