> From: "Matthew J. Dovey" <[log in to unmask]>
> To be honest, I'm not sure whether the terms "surrogate/non-surrogate"
> diagnostic is necessarily useful and is really a hangover from Z39.50
> terminology.

There still is a distinction but it has changed from Z39.50.

Take a look at http://www.loc.gov/standards/sru/specs/diagnostics.html.

There is now a distinction between fatal and non-fatal diagnostics.
Non-fatal diagnostics are divided into 'surrogate' and 'non-surrogate'. So
the distinction remains but has changed considerably from Z39.50.

The key difference is that you can now (in SRU) have a "non-surrogate,
non-fatal diagnostic". That is, you can include in the response a diagnostic
not connected to a specific record, while also including records in the
response. You can't do that in Z39.50 which is something people complained
about for years so we fixed it in SRU.

--Ray