[rescue] Netra NFS/Enterprise 150 question

Sandwich Maker adh at an.bradford.ma.us
Sat Feb 7 14:37:50 CST 2009

" From: Mike Meredith <very at zonky.org>
" On Sat, 7 Feb 2009 14:24:18 -0500 (EST), Carl R. Friend wrote:
" >     On Sat, 7 Feb 2009, Bill Bradford wrote:
" > 
" > > Unfortunately they *completely* dropped drivers for other parts of
" > > the U1 as well - he'd only be able to run really early revisions
" > > of the OpenSolaris code.
" > 
" >     There's also the "issue" that it's apparently possible to wedge
" > the early Ultra chips when running in 64-bit mode.  I know that I
" > had to invoke some magick to get Solaris 8 to boot in 64-bit mode
" Yes it's possible to wedge an Ultra-1 cpu in the same sense as it is
" possible to find two files that give the same md5 checksum. Or in other
" words you're not going to find it unless you hunt for it. I ran such a
" machine in production running a 64-bit kernel for years without a
" problem. Ok I wouldn't have done if students were logging in and
" compiling code(*), but for a dedicated name server it was fine.

i've been running a succession of u1s in 64b s8 for 4-odd years now
without incident.  what decided me was reading a paper that said the
opcode combination needed to crash the chip -could-not- be emitted by
any compiler and needed to be handcrafted specifically - iow, you
couldn't stumble across it accidentally.

" Of course later versions of Solaris 10 (I _think_ the early versions
" just printed an error that amounted to saying you can't run this on
" ancient hardware) may have Done Something Dumb to exercise that cpu
" bug. Or possibly the code that displays the error has become very
" broken.

i think they just try to use features that aren't in the u1 chip.

" *: In practise the biggest problem of allowing students to login to a
" multiuser machine and run code is that they were taught at $work to
" turn off the optimiser (because "it changes your code") and were under
" the impression that an infinite loop that didn't do anything would
" eventually exit. And would try it again on another "terminal" just to
" check. Fortunately a V880 running Solaris 9 can run a very large number
" of infinite loops that don't do anything.

the shallow end of the gene pool.  even when i was a student i knew
Andrew Hay                                  the genius nature
internet rambler                            is to see what all have seen
adh at an.bradford.ma.us                       and think what none thought

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