[Info-vax] OpenVMS servers and clusters as a cloud service

[Jan-Erik Soderholm]

Den 2018-01-01 kl. 23:37, skrev Arne Vajhøj:
> On 1/1/2018 2:54 PM, Arne Vajhøj wrote:
>> On 1/1/2018 2:41 PM, Scott Dorsey wrote:
>>> So in general it is less common than it once was.  You still see it on a 
>>> lot
>>> of VMS systems because they tend to be run by people from 30 years ago.  
>>> But
>>> the kids don't know about it, they view it as esoteric and complicated, and
>>> they need to be told how easy and convenient it is.
>>
>> Even on VMS it is my impression that a lot of systems only run one
>> thing: RDB or Oracle DB or that COBOL application (sure - usually
>> more than one program but still part of the same application)
>> or that Fortran application or that XXXX.
> 
> One exception I think - I believe it is way more common
> to run both application and database on the same system
> on VMS than on other platforms.
> 
> Arne
> 

If it is Rdb (which run all database operations within the user
process space), it is very common to have the database on the same
system as the application using the database. One can also use "Rdb
remote" between systems, of course. Even between different platforms.

Most other database usualy use a network link (even if it is to
"localhost") to a server process that is shared by all processes
that runs applications doing database jobs. In those cases it is
more straight forward to split applications and database processing
over multiple systems.

So the actual Rdb database code is linked (via a shareable image) to
the application EXE itself. And each application processes directly
opens the database files.