Subj : FreeBSD 4.3-RC buffer issue
To   : Tobias Ernst
From : Lawrence Garvin
Date : Mon Apr 16 2001 03:27 pm

Tobias wrote to Lawrence at 12:56 15 Apr:

 TE> Hallo Lawrence!

 TE>> FreeBSD for sure works on a non-Pentium machine,

 LG> version 4.x?

 TE> Yes.

Thankyou, also, Tobias.. for the confirmation.

 TE> I don't think they are. In order to create binaries that are no
 TE> only Pentium optimized, but really use Pentium instructions which
 TE> 486 or 386 CPU's do not understand, you would have to use a
 TE> compiler which indeed does make use of Pentium-speicifc
 TE> instructions.

The C compiler that shipped with SCO OpenServer had this capability. A flag on 
the compiler command line could enable Pentium optimizations. Otherwise, it was 
compiled for i486 code.

 TE> FreeBSD 4.x, however, is compiled with gcc 2.95.2, with just "-O" 
 TE> as optimization flags, and that version of the GNU compiler does 
 TE> not know anything about pentium instructions.

'K.

 TE> The only critical part could be the FreeBSD kernel, which contains
 TE> some assemblies which could make use of Pentium-type instructions.
 TE> However, there are options in the kernel config, with which you can
 TE> enable or disable use of those instructions, and given that the
 TE> default GENERIC kernel of FreeBSD contains a 

 TE> cpu I386_CPU

 TE> config statement (among others for 486, 586 and 686), it is obvious
 TE> that they at least intend to support plain 386 type CPUs with this
 TE> kernel. 

Presumably this may enable/disable IFDEF type code in the kernel -- albeit at 
run time, rather than compile time? 

 TE> I have no such machines left, so I can only make theoretical
 TE> arguments, but I really see no reason why FreeBSD 4.x would not
 TE> work on those machines. 

I've got a 386DX/40 systemboard in a case somewhere in my warehouse. But, it 
begs the question of whether the BIOS on that board will support a drive large 
enough to install. I know that FreeBSD 4.x is 4 CDROMs of stuff... how much 
disk space is required for the core system?

 TE> FreeBSD's philosphy has always been to put stability in front
 TE> before any sort of experimental fine-tuning. And even Linux is
 TE> shipping with i386 binaries per default. If you want Linux with
 TE> pgcc-compiled binaries you need to use one of the few special Linux
 TE> distros that ship with this sort of binaries. 

Thanks for the info!

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