[Info-vax] Suggestion: Enhance DCL to support proper escape quoting.

[Johnny Billquist]

On 2022-01-28 13:09, Paul Hardy wrote:
> Johnny Billquist <bqt at softjar.se> wrote:
>> The "worst" of it is when you need to juggle things a lot in order to
>> fit it all in. That can be quite an exercise. Multiple co-trees,
>> figuring out dependencies, and writing the ODL file for it all.
>>
>> When I backported DUNGEON V3.2 to RSX, I really had to work hard on
>> that. Probably the most complex thing I've ever done. I think I ended up
>> with 10 co-trees, and all kind of cruft. I would agree that they are not
>> the most fun, but you sortof live with them and accept them. Sure, I can
>> understand people who felt relief when moving to VMS, and never having
>> to care about that again.
>>
>>    Johnny
>>
> 
> For big programs with many complex overlays it was hell to debug overlay
> tree calling mistakes. You should only call to branches up the current tree
> or down towards the root of the current branch. If you called across to
> another parallel branch it all worked until you tried to return from the
> call , where the rest of the calling routine had been overlaid and
> obliterated. I remember several late nights debugging such for an early
> digital mapping system on RSX11M.

Well, technically you can't jump between branches. Not directly. (The 
namespace for a different branch isn't visible, so you cannot refer to it.)

But I know what you mean. If you call up (down?) towards the root, you 
can from there go down another branch, and then when you are returning, 
at some point you will return to a branch that isn't in memory, and all 
hell breaks loose.
And I agree, this is not nice to try and figure out.

I do have an application that actually is doing this, deliberately. But 
the routine in the root is made aware from which branch it was called, 
and before returning, it makes sure that branch is back in memory again. 
But it's not the most fun thing...

> Moving to the flat address space of VMS was a delight!

Yes. From the overlay landscape it was. That was, however, also the path 
towards huge software and libraries where you no longer can understand 
what it all does. And from that perspective I prefer overlays... :-)

(Not to mention there are a bunch of things that I just feel are better 
in RSX than VMS, but of course there are things better in VMS as well...)

   Johnny