Dual BSD/S5 UNIXES

[Shaun ARundell]

Pyramid is not the only vendor to offer a Dual ported UNIX.

Gould's UTX/32 (releases 1.3 and above) offer a similar
facility, as do a number of other vendors. 

Any body who has worked in a post sales position in the last
year or so will see why this is necessary, at least from an
economic standpoint.

A large number of the tenders that have come out recently have specified
a particular version of UNIX as a mandatory. Most Universities
and DOD sites specify BSD4.2 has necessary and a lot of commercial
sites specify S5V2 as becessary. This means that a vendor has the
choice of offering one varient and losing business or offering

	A - S5 and BSD4.2 seperately
	B - A superset
	C - A Dual port

Choice A is usually ruled out as too difficult to maintain (every support
site would need access to two machines or have to reboot to move
from one UNIX to the other)

Choice B was the track that GOULD had first taken (with the help of
the BRL emulator). This caused a lot of flack from system adminstrators.
Some commands behaved in fashion that was neither pure
BDS 4.2 or pure System V.

Choice C is Gould's current strategy. There is a /usr/bin and a /usr/5bin
a /usr/lib and a /usr/5lib a sv and a bsd command, etc.

Having worked on  Pyramids, Goulds and single SV5 and BSD4.2
machines, I favour choice C. Choice A is unweildy. Choice B is 98% ok,
but those 2% of commands that behave funny cause real headaches.

It is really fairly easy to do a dual port. Both Pyramid and Gould
started off with a BSD kernal added some S5 support (mainly IPC) and
then just wrote two lots of system libaries. All the different /bin,
/usr/bin, /usr/ucb, etc. just compile straight in. If your carefull
how you do your kernal, updating to BSD4.3 and S5V3 is fairly straight
forward. There are a few gray areas with signals and terminal handling
but both Pyramid and Gould have solved these issues in a workable
fashion.

Anthor real problem is init, ttys (and some other /etc stuff).
Pyramid has done a superset, Gould stuck with the BSD stuff.

I see the real point as offering the USER (both system supervisor
and general user) not just both lots of commands but a choice.
With the current length of stay for UNIX programmers being 7 months
he bounces between S5 and BSD systems on a regular basis. With a
dual port he has all the tools and facilites he is use to.
A dual port also allows the vendor to go for all the
UNIX tenders not just his particular varient.


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