[Info-vax] OpenVMS STARTUP Whitepaper

[Jan-Erik Söderholm]

Den 2020-12-11 kl. 13:55, skrev Craig A. Berry:
> 
> On 12/10/20 11:28 PM, David Jones wrote:
>> On Thursday, December 10, 2020 at 8:57:16 PM UTC-5, Stephen Hoffman wrote:
>>> SQLite can be useful for storing the data, particularly for those
>>> without Oracle licenses and that for whatever reason.
>>
>> Using Oracle in your startup sequencer means you have to start it before 
>> you can run
>> the thing that starts it -- somewhat problematic. A cloud-based database 
>> still needs the
>> network running. I link the startup driver application statically with 
>> the sqlite3 library
>> and run it with the data file flagged as immutable (readonly, no locking).
> 
> I believe in the case of Rdb there is no start-up because there is no
> service -- you just link your code against the libraries and run it in
> the context of whatever process.  In other words, the same way you are
> running SQLite.
> 

For Rdb, you need to run the RMONSTART.COM to start the "monitor".
That COM file also install the sharable images that each "user"
process links to at each image startup.

The monitor is not doing any database "work", it just monitors Rdb
and does tasks such as starting recovery processes in the case that
a user process dies.

The actual database "work" is done by each individual user process
using the code in the Rdb sharable images. So thet works directly
against the database files without involving any database server
process, which is the usual setup for most other databases. Maybe
not SQLite, though...

So no, you cannot use an Rdb based startup sequencer before you have
run the startup for Rdb. But you can for any application management
on the running system, if one like.