[Info-vax] Pointless Nostalgia: System Service Dispatching

[lawrencedo99 at gmail.com]

On Friday, July 1, 2016 at 4:54:03 AM UTC+12, Michael Moroney wrote:
> $QIOW (and most $xxxW services which also have a corresponding $xxx service)
> are implemented as a $QIO followed immediately by a $SYNCH of the specified
> event flag/IOSB pair.

That was the one. Originally it was a simple $WAITFR, but this was replaced with the more robust $SYNCH in VMS V4 or something.

> I believe only $HIBER can potentially be re-executed.

All the process-blocking ones, including $SYNCH and all the $WAITxx calls, were restartable.