[Info-vax] naming convention in VMS MAIL

[Arne Vajhøj]

On 12/19/2018 8:29 PM, Dave Froble wrote:
> On 12/19/2018 7:36 PM, Stephen Hoffman wrote:
>> The core OpenVMS design features are inherently slow.  SSDs have helped
>> there as have caching controllers, but the default behavior is a write
>> to persistent storage.  There are more than a few cases where that's
>> less than desirable, or where it would be preferable to cache a bunch of
>> operations and flush that data less frequently.  That's certainly
>> possible on OpenVMS, but OpenVMS isn't good at presenting this trade-off
>> to the developers.  There've been cases where—for instance—temporary
>> stub files opened and written and closed frequently can utterly saturate
>> a system.  Bad design, but other systems can keep all that in memory
>> until flushed, so the storage I/O paths don't get hammered.  And
>> clustering works because the data is on static storage and the OpenVMS
>> I/O caches are usually write-through and not write-back.  Trade-offs
>> abound here, of course.
> 
> And some of us are rather happy with that.  When I do a write, I really 
> want to believe that the data is truly written.  One can mention 
> batteries, UPS, and such, but, that doesn't give me the same warm fuzzy 
> feeling.

Yes.

While it can be difficult on VMS to get enough caching to make IO fast
then on other platforms and technologies it may be a problem how to
disable caching to avoid the risk of data loss.

Arne