[Info-vax] Shared Stream IO (SSIO) beta kit available for OpenVMS

[Stephen Hoffman]

On 2013-01-28 12:54:57 +0000, Neil Rieck said:

> This is great news. Thanks for working with HP OpenVMS Engineering to 
> have this developed. (speaking of UNIX portability, any idea if you can 
> get them to implement a true fork?)

I can save Bill the trouble, here.

Fork is not going to happen on VMS.

Ever.

There are existing DEC/Compaq/HP C fork-related routines available 
which make porting ~95%[1] of the C code using fork() fairly easy, but 
that last ~5%[1] of the C code around is really using the true, full 
capabilities of fork(), and analogs of those capabilities are not 
available on VMS due to the low-level architectural differences between 
VMS and Unix.  The copy-on-write memory management and the differences 
in I/O channel contexts being two examples of this.

Could fork() be implemented?  Sure.  But that means either massive 
complexity and untenable overhead, or ripping up the kernel.  Or both.

————
[1]I'm quoting those percentages from memory, but those numbers should 
get you in the range.


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