On 12/2/05, gwtmp01 / mac.com <gwtmp01 / mac.com> wrote:
>
> On Dec 2, 2005, at 9:28 AM, Eric Mahurin wrote:
> > What does "COW" mean?
>
> copy on write
>
> http://en.wikipedia.org/wiki/Copy-on-write

Thanks.  It looks like the normal COW usage from this wiki is when the
shared resource starts and ends at the same memory locations for all
uses.  I think the conventional COW as described above would apply to
Array#replace and Array#clone, but not Array#slice.  The way ruby does
COW is clearly a win for Array#replace and Array#clone, but not for
Array#slice (and many others) as demonstrated in my example.