csh pgrp problem

[Terry Friedrichsen]

In article <920 at legato.LEGATO.COM>, mojo at legato (Joseph Moran) writes:
> Folklore
> has it that vfork was created solely for csh because of the performance
> costs of csh doing Unix fork's in a paged environment without
> copy-on-write.

And WHY was there no copy-on-write?  In "Design and Implementation of
4.3 BSD" (title paraphrased from memory), the authors write that copy-on-write
was considered and abandoned because a microcode bug in one model of VAX
made it questionable that copy-on-write could be reliably implemented.

They don't identify the model, though, so it's hard to say whether it would
have been better to write off that VAX instead of writing vfork().

Terry R. Friedrichsen
TERRY at SDSC.EDU  (alternate address)

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