Hi,
new idea after googling and finding several examples like Dan Ritter's
proposal:
Try the "exact path" form of "suite":
deb file:///home/richard/dvdmount pool/main/
deb file:///home/richard/dvdmount pool/contrib/
or the usual form without mentioning (demanding ?) "stretch":
deb file:///home/richard/dvdmount pool main contrib
Reasoning:
You report this program message:
> The repository 'file:/home/richard/dvdmount/pool stretch Release'
> does not have a Release file.
/mnt/iso/pool has "main" and "contrib" but no "stretch".
man 5 sources.list says:
deb [ options ] uri suite [component1] [component2] [...]
[...]
can specify an exact path, in which case the components must be omitted
and suite must end with a slash (/). This is useful for the case when
only a particular sub-section of the archive denoted by the URI is of
interest. If suite does not specify an exact path, at least one
component must be present.
Suite "stretch" is neither "exact path" nor does it appear in the pool
tree of DVD 1.
Further for the "exact path" case:
In the traditional style sources.list format since only one
distribution can be specified per line it may be necessary to have
multiple lines for the same URI, if a subset of all available
distributions or components at that location is desired.
Thomas