[Info-vax] DCL, DLM, APIs, RAS, RuleWorks, etc

[Stephen Hoffman]

On 2022-10-27 21:20:50 +0000, Dave Froble said:

> On 10/27/2022 2:03 PM, Stephen Hoffman wrote:
>> 
>> The DLM API was and remains a nice box of parts arising from the 1980s, 
>> and does still work and does work well, but the API is really showing 
>> its age.
> 
> Good ideas can have a length lifespan.
> 
> But I confess to curiosity, what would a better API for the DLM look 
> like?  I've used it from Basic, and anything one can use from Basic has 
> got to be rather simple.


Off the top...

Every peer process joining the peer group makes a call with some 
parameters, and each then gets a startup AST, and one peer process then 
gets the primary AST. Each joining process will initially get the 
startup AST, and will alway get the startup AST before the primary AST 
arrives. Any peer process may or may not get primary. The initial 
primary gets an uninitialized context block of 64 bytes (with an 
indication that the context is uninitialized/zeroed/invalid), and every 
subsequent process becoming primary gets the latest contents of that 
same context block. The primary can use that context block to request 
all peer processes perform a controlled exit (as they sequentially 
become primary) or whatever other means to communicate that, and/or can 
use the context block for passing around counters, and/or status, 
and/or whatever.

Basically, one call with an argument list containing the peer group 
name, two AST arguments, a context block, and maybe a context 
parameter. No itemlists. The call itself stalls or hibernates in user 
mode, waiting for something to happen.



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