[olug] Question regarding *BSD vs Linux kernel (was: Re: SuSE or RHEL or Centos or Fedora or Xandros)

[Daniel Linder]

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<quote who="Sean Edwards">
> Since my *BSD days are far behind, this may no longer
> apply. The most important difference is the TCP/IP
> stack.  With Linux, there is a buffer between the
> kernel and the TCP/IP stack, but with BSD there is no
> bufffer, the network and TCP/IP stack are more tightly
> integrated with the kernel, adding stability and
> reliablity to network services.

Is this still true?  I remember "way back when" (i.e. 1998/1998 timeframe)
that BSD servers spanked neary everything else when the hardware was the
same because the NIC drivers were so tightly integrated into the OS.

My feeling is that this is a "bad thing" -- just look at Microsoft Windows
NT 3.51/4.0 as an example.  To help speed up their video speeds, they
allowed the drivers run right along side the WinNT kernel (both in
"ring-0" of the CPU).  This allowed the drivers to access the RAM and
video memory directly but a buffer-overflow or other programming error in
the driver could over-write other applications memory or bring the system
to a halt.

If the *BSD drivers are written with proper buffer-overflow
protection/monitoring -- I believe OpenBSD requires this (note 1) -- then
it is a performance improvment.  For those of us who don't want an
un-expected event to kill our server I'd rather take the 0.1% performance
hit. :)

Dan

Note 1: I think the OpenBSD compiler places a 16-bit random-but-recorded
value on the end of each variable.  Then periodically the system checks
all these values against what it generated when it loaded the application
and terminates any application that has modified these values (i.e. a
possible buffer overflow).  IMHO, a neet idea.

- - - - -
"I do not fear computer,
I fear the lack of them."
 -- Isaac Asimov

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