[Info-vax] OS implementation languages

[Arne Vajhøj]

On 8/30/2023 4:53 AM, Johnny Billquist wrote:
> Not sure how easy it is to dodge RMS under VMS. In RSX, you can just do 
> the QIOs to the ACP yourself and go around the whole thing, which makes 
> I/O way faster. Of course, since files still have this structure thing, 
> most of the time you are still going to have to pay for it somewhere. 
> But if you are happy with just raw disk blocks, the basic I/O do not 
> have near as much penalty. Admitted, the ODS-1 (as well as ODS-2) 
> structure have some inherent limitations that carry some cost as well. 
> So you could improve things some by doing some other implementation on 
> the file system level.
> But mainly, no matter what the file system design is, you are still 
> going to have the pain of RMS, which is the majority of the cost. And 
> you'll never get away from this as long as you use VMS.

SYS$QIO(W) for files works fine on VMS too.

But a bit of a hassle to use.

There are two alternative ways to to bypass RMS:
* SYS$IO_PERFORM(W) - the "fast I/O" thingy
* SYS$CRMPSC - mapping the file to memory

Arne