Maybe a better example would be something like
reconstituting an
application where the owners of the property rights are defunct (dead
companies) or even the owners don't have the source anymore.
Another example I can think of is where you have a piece of test
equipment whose operation depends upon software for a computer that is
no longer generally available.
The Biomation CLAS 4000 logic analyzer, for example, is a SCSI device
whose user interface runs on a 68000 Macintosh.
Firmware/software for test equipment is one area in particular that
points out the problem of devices becoming boat anchors because the code
to control them wasn't preserved with the device.
The trend in the past 10 years to produce subscription devices that
depend on a host run by a company that no longer exists (Richochet,
Catapult, Kerbango, ...) is another annoyance.