[TUHS] SVR4 vs. Solaris 2

[Clem Cole via TUHS]

My memory is a bit hazy here so Tom or Larry are probably better sources
but … IIRC they were close but not 100% identical. Remember Sparc was not a
reference platform for SVR4 (386/486 were). The big thing Solaris lost was
the work SunOS had done in the memory system. I never knew for sure, but I
think that was a big reason the boot/init and the command system became
AT&Ts version.  However some of the earlier SunOS value add was put back
in.

For instance my memory is that Solaris could use sockets while SVR4 still
was pushing TLI/Streams plus Solaris supported Sun Threads as well as
pthreads while SVR4 was only pthreads. Also I don’t remember if SVR4 had
dtrace which was a huge advantage.

 I also believe the compilers were different. As Sun had early had
(finally) invested in their own compilers with CMU/DEC style code
generators and optimizers; while AT&T was still using PCC2. Interestingly
enough because Sun was charging for their new compilers suite many end
users/customers installed the Gnu family.

Sent from a handheld expect more typos than usual


On Tue, Nov 11, 2025 at 9:05 PM segaloco via TUHS <tuhs at tuhs.org> wrote:

> Pardon if this question has already been asked and answered
> before, but I find myself curious.  System V Release 4 was a
> joint effort between USL and Sun, which involved contributions
> from both parties as well as other improvements.
>
> I often see it suggested that the first version of Solaris was
> SVR4 itself, but my question is: Was the initial stock Solaris 2
> release identical to USL SVR4, or were there still additional
> value-adds that Sun made to the inaugural release of Solaris
> beyond just the joint SVR4 trunk resulting from the project
> between the two organizations?  In other words, when one
> purchased and installed the initial release of Solaris, were they
> in essence also installing SVR4 from USL, or was there some
> appreciable difference?
>
> - Matt G.
>