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

[Stephen Hoffman]

On 2013-01-28 21:43:22 +0000, Johnny Billquist said:

> On 2013-01-28 14:31, Stephen Hoffman wrote:
>> Could fork() be implemented?  Sure.  But that means either massive
>> complexity and untenable overhead, or ripping up the kernel.  Or both.
> 
> copy on write is not a semantic of fork. It's just a very nice optimization.

With the inverse of "a very nice optimization" being "untenable 
overhead".  Lacking copy on write means spending a whole lot of time 
and processor effort replicating the contents of process address space 
around.  Sure.  Watch your cores all spin up with buffer copies, 
transferring the contents of process memory through a window and into 
the new process.   An effort which would often be followed immediately 
by tearing everything down, for the percentage of fork() calls that 
don't use that feature, too.

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