From: Brad Reger (reger@millis.esd.sgi.com)
22 Dec 1994 16:29:19 GMT

>:I have some some new Indigo2 boxes which, I am told, have the XZ graphics
>:package. However, the hinv tells me that the graphics card is "GR3-Elan".
>:How do I determine whether I have Elan or XZ graphics?
>
>|GR3 is the XZ board. GR2 is Elan. GU1 is Extreme.

While this may be true, I suspect it isn't very interesting to
most people. What our marketing folks want to call things doesn't
usually matter that much either except that it's the customer-visible
name. To confuse matters, we in engineering (along with marketing)
sometimes change things in hardware or software, but leave the
marketing name the same. We'll never (consciously) remove a
feature, but there have been times where we've added things and
left the name the same. XZ is an example.

Purple Indigo:
Entry graphics has no hardware GE (it's done in s/w)
XS graphics has 1 GE
XZ graphics has 2 GE's
Elan graphics has 4 GE's

Original Green Indigo2:
XL has no GE's (done in s/w again)
XZ had 2 GE's
EX has 8 GE's

Later Green Indigo2:
XZ has 4 GE's

Some history (my interpretation):

Purple Indigo came out with Entry graphics. Great machine.
Great price. Graphics just okay. Most people wanted more
bitplanes and the option of putting in a hardware Z-buffer.

Elan graphics comes out in purple Indigo. Excellent graphics.
Completely blew away anyone else doing desktop 3D graphics.
Along with Elan, we came out with XS (1 GE) with optional
hardware z-buffer and optional 24-bit. Now have high, medium
and low graphics configs.

Turns out the market really wanted 2-GE performance. One
wasn't quite enough and 4 was too expensive. So we came out
with the XZ. Now have the performance of 2 GE's, 24-bit,
and standard hardware z-buffer. Great product. Sold lots
of 'em. [this may have happened after the Indigo2 intro]

Green Indigo2 comes out. Intro with high-end EX graphics
(8 GE's and double the raster performance). Best graphics
on the desktop. A quarter later we intro the XZ (2 GE) config
and one quarter after that we intro the XL (0 GE) config.
All three sell well. As competition heats up (and some things
become possible in hardware) we realize the XZ needs a boost.
We bump the Indigo2/XZ from a 2 GE config to a 4 GE config.
Nothing else changes, including the name. We figure people
will be happy to get more for the same price. Problem is,
people get confused and ask lots of questions.

Now on to 'hinv'. As far as identifying graphics configs, it
uses a pretty simple algorithm. It first looks at the base
graphics board (LG*, GR*) and then just counts the number of
GE's it sees. Then it goes through a fixed mapping of #GE's
to marketing name. GR2 is purple (or brown). GR3 is green.
So you get GR2-XZ if it sees a GR2 board and 2 GE's. You get
GR3-XZ if it sees a (green) GR3 board and 2 GE's. When it sees
4 GE's it wants to call that an Elan. So you'll get either
GR2-Elan (purple) or GR3-Elan (green). Since we never had an
Elan product in green, you now have to interpret this as the
4 GE version of XZ.

Long-winded. Did I explain enough?

--
Brad Reger                                              reger@sgi.com
Hardware Systems Engineering
Silicon Graphics - Interactive Systems Division (green & purple boxes)