I’m trying to get to the bottom of something… And I am still not sure if the information I am receiving about this issue is correct. Anyway… The ADABAS ADARUN (ADA7.4.4) parms for the active session shows “MODE=SINGLE” (this is in the start-up messages); however, when database 215 actually starts up, the messages show:
ADAN01 00215 A D A B A S V7.4.4 is active
ADAN01 00215 MODE=MULTI
ADAN01 00215 Running without recovery log
The question is, if the PARM specifies MODE=SINGLE, why would the nuc come up as MODE=MULTI?? Are there certain conditions that would cause this?
Thanks for any advice. (I will also post this in other boards.)
Mode=SINGLE is an ´old´ method which was invented long time ago when the cross-memory communication cost a lot of CPU cylcles. It does start an Adabas nucleus in the same address room as the client and will do the call directly as a Branch instead of a call via the SVC.
We don´t recommend to use this anylonger, it is only there because of compatibility.
If it is used to ´protect´ the nucleus from beeing reachable by all clients (i.e. CICS users etc) we recommend to use the adarun parameter UTIONLY or READONLY.
The MODE=SINGLE behaviour dependents on the setting of the ADARUN parameter PROG=, i.e. for PROG=ADANUC this parameter is ignored, it makes only sense for utitilies or batch programs which issue Adabas calls. The Adabas nucleus doesn´t call itself, so it is senseless to use MODE=SINGLE, therefore it is ignored.
There are other utlities like ADASAV where this parameter is also ignored, because this utility does ´it´s job´ not via Adabas calls. So no benefit to load the nucleus in the same adress space