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Date: Wed, 15 Jul 1998 18:42:13 -0700 (PDT)
From: Joseph Koshy <jkoshy>
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(http://freebsd.stanford.edu/FreeBSD/linux.html)

Some answers to your questions with parenthetical comments needing further
discussion by the list in curly braces "{}".

Q: Do gcc and cc work the same under FreeBSD as they do under linux? 
A: Fundamentally yes.  The version of GCC in the current FreeBSD
   release is "v2.7.2.1" and this should behave identically to a GCC v2.7.2.1
   compiler under Linux.

   Numerical programs using floating point may sometimes show different
   behaviour;  FreeBSD does not by default mask off floating point exception
   conditions like numeric underflow or loss of precision and will attempt to
   notify the program using a signal when this happens.  If the program has 
   not arranged to handle this signal, it will be terminated by the kernel.

   Some {all?} versions of the Linux kernel do not enable detection of these
   numeric exceptions by default, and consequently the same programs will run 
   without apparent errors under Linux.  The accuracy and reliability of the
   results generated may not be that expected however.

   { Is this description accurate? }

Q: Does FreeBSD run ELF binaries? (Is that the right question?) 
A: Yes, FreeBSD can run ELF binaries without any problem.
   Linux ELF binaries work fine too under Linux emulation, though older 
binaries
   may need to be "branded" before use using the `brandelf' utility.

   { There is a (small) section on "branding" in the Handbook, we could 
     point people to this: ``23.1.4. Installing Linux ELF binaries''.}


Q: Will I be able to mount Linux file systems under FreeBSD? 
A: Yes, you can mount Linux "ext2" file systems under FreeBSD.  Use

   # mount -t ext2fs /dev/wd0s1 /mnt
                     ^^^^^^^^^^
		     this is the device name for your linux partition

   Note that the device numbering scheme used by Linux is different from
   that followed in the BSD world.  For example, "/dev/hda" under Linux
   could appear as "/dev/wd0s1" under the BSD naming scheme.


Q: Can I install FreeBSD on the same hard drive as Linux?
A: Yes.  You can install FreeBSD in another primary partition on the hard
   disk.  

   { You can even arrange for FreeBSD to use Linux's swap partition,
     (there was a discussion on this point on -hackers sometime
      back), but this may be a bit advanced for a introductory howto. }

   { Note: I think that the default bootloader "booteasy" doesn't
     support booting from a secondary ("extended") partition.  Is this
     correct?  }

   { We could point people to the FreeBSD+LILO HowTo on the WWW and the
     FAQ entry on this topic too. }

Q: If I install FreeBSD on the same computer on which I've got Linux, will    
   Linux lilo work? 
A: Yes.  See the FAQ ``How do I boot FreeBSD and Linux from LILO?'' 
   and ``How do I boot FreeBSD and Linux using BootEasy?''.


--
Koshy
<jkoshy@freebsd.org>


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