On Sun, 13 Mar 2005, Olmsted, Brian wrote:

[snip]
> My understanding is that the NetApp Filer DataOnTap OS is based on
> NetBSD if that helps with understanding the TCP/IP stack.  That is,

Nope, ONTAP is *not* Unix-based.

I believe they started with a real-time kernel and wrote the rest from
scratch - it may look very BSD-like on the surface, and it follows a lot
of Unix conventions so that Unix admins could very quickly learn to admin
the machines.  But, for example, ONTAP services NFS requests right in the
network interrupt handler - which is how they post SPEC SFS numbers with
ORT < 1.0ms...

Of course, ONTAP has grown into a far more complex OS in version 7.x than
it started out as; early versions were very "lean and mean", but feeping
creaturitis has set in over the years... but while it is Unix-like, it is
definitely not a Unix-based OS.

-- Chris

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