Re: [Networker] 64 v 32 bit

In regard to: Re: [Networker] 64 v 32 bit, Thorsten Linow said (at 12:52pm...:

Hi,
If Your driving Your car and You're in a hurry, speedlimit is 80 mph, no 
traffic on the road at all and Your
car ist fast enough. Would You drive 40 or 80 mph?


Although I'm a proponent of 64 bit computing, I don't think your analogy
is a particularly good one.

First, although it's possible that LP64 binaries will run faster than
ILP32 binaries, it depends on the platform.  You can't make that
assumption in general.  Often they will run slightly slower (again,
depending on the platform).  I've been using LP64 platforms since
the early 90s, and I have yet to see a scenario where some package
will run twice as fast in LP64 mode vs. ILP32.

Second, LP64 binaries certainly require more RAM, especially if the
program makes heavy use of pointers.

Third, even in this day and age, programmers tend to assume "all the
world's an ILP32 platform", so you're more likely to encounter programming
errors in an LP64 build.  The same poor assumptions are there in the
ILP32 build, they just don't affect you as they would on an LP64 build.
As anyone that's ever run the "networker" GUI on Tru64 can tell you,
they're there (unaligned accesses).

In other words, why installing either a 32 bit Operating System or 32
bit Application if Your platform is a 64 bit one.  As long as it is not
mandatory to another application to run the 32 bit OS, it makes no
sense. On the other hand
It's also a question of Support. As far as I know it's even not
supported to run a 32 bit solaris on a 64 bit Platform.


I don't know about the OS itself (though I suspect it *is* supported,
I could certainly be wrong), but we're talking about an application here.
It certainly *is* supported to run a 32 bit app on Solaris 8, whether the
kernel is 64 bit or whether it's 32 bit.

 Or why qould
You buy a 64 bit machine for backup purposes if You could use a 32 bit
instead?


There could be lots of reasons.  Perhaps they're completely a
Sun/sparc/Solaris shop?  Sun only sells sparcs that are 64 bit-capable
these days.

-Have a 64 bit environment: use it!


What should be driving the decision is not the "I have a hammer, so I'm
going to use it" scenario, but features and functionality.

-  Is a 32 bit version of NetWorker supported on your server platform?
   I think it is, but I could be wrong.

-  Are there things that the 32 bit version can't do that the 64 bit
   version could do?  Do you want/need those things?

   The only obvious one for me is "address more than 4 Gig of virtual
   memory".  It's *possible* that the 32 bit version also doesn't handle
   partitions as large as the 64 bit, or perhaps even Large File Support
   (LFS), but I'm pretty skeptical.

I would read carefully the release notes and relevant documentation for
the ILP32 build and for the LP64 build, and see if the OP can find anything
compelling *for their environment* (what's compelling for my environment
might not be for theirs).

Tim
--
Tim Mooney                              mooney AT dogbert.cc.ndsu.NoDak DOT edu
Information Technology Services         (701) 231-1076 (Voice)
Room 242-J6, IACC Building              (701) 231-8541 (Fax)
North Dakota State University, Fargo, ND 58105-5164

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