Introduction
 The
SGI Indigo is a very nice machine but maybe a bit too old and
too slow for much serious work. It guess its mainly a collectors
item and you still see some of them on ebay from time to time,
but in most cases they get more expensive than an Indigo²
or Indy which would offer more performance.
1. CPU and Mainboard
Basically there were two types of mainboards and three different
CPUs:
| Mainboard |
CPU |
Memory |
| IP12 (HP1) |
R3000A at 33MHz |
8MB - 96MB proprietary modules |
| IP20 (HP2) |
R4000SC at 100MHz |
8MB - 384MB PS/2 modules |
| IP20 (HP2) |
R4400SC at 150MHz |
8MB - 384MB PS/2 modules |
If you want to work with your Indigo, you really should get an
IP20 Indigo with at least 100MHz. The 150MHz Indigos are rare,
but you can also plug in a 150MHz CPU module of an Indy into the
Indigo. The older IP12 based 33MHz Indigos aren't really fun any
more for serious work!
2. Memory
As you can also see in the table above, older IP12-based Indigos
need special RAM and offer only limited possibilities for RAM
upgrades. The IP20 based Indigos need standard PS/2 FPM memory
with parity - this shouldn't be a problem to find on second hand
markets or ebay.
You should have at least 32MB of memory - as always more is better
especially for newer IRIX releases. For IRIX 6.5 you really should
have at least 128MB of memory.
3. IRIX Compatibility
Not all versions of IRIX run on the old IP12-based Indigo with
the R3000 processor. The newest version that you can use is 5.3.
And if you only have 32MB of memory or even less, you really should
consider running IRIX 4.0.
On the other hand, the newer IP20-based Indigo will run IRIX
up to version 6.5 - but you really should have at least 128MB
of memory.
3. Graphics
Essentially there are two different graphics architectures available:
The older 'Entry' graphics and the newer 'Express' graphics. The
first one has only 8bits of colour and absolutely no hardware
acceleration. But it comes with a standrd VGA connector instead
of the 13W3 connectors. The express graphics architecture has
many different possible variations with the best being the 'Elan'
graphics card. Theoretically you can upgrade every express based
graphics card up to Elan simply by adding a Z-Buffer module, memory-modules
for the framebuffer and geometry engines - but don't count that
you will find these anywhere on ebay.
This table lists most of the possible configurations of an express-styled
graphics card. Again, the more framebuffer and geometry engines,
the better it is.
| Name |
Framebuffer |
Z-Buffer |
GEs |
| XS-8 |
1 module (8 bit colour) |
no |
1 |
| XS-24 |
3 modules (24 bit colour) |
no |
1 |
| XS-24Z |
3 modules (24 bit colour) |
yes |
1 |
| XZ |
3 modules (24 bit colour) |
yes |
2 |
| Elan |
3 modules (24 bit colour) |
yes |
4 |
You really should get an express based graphics card, as it is
much faster than the old newport architecture.
Note that there is no option available for the Indigo with hardware
accelerated textures - if you need these, you have to get an Indigo²
or Octane
with hardware texturing or an O2.
4. Disc Drives
One harddisc should be enough for your system. The size depends
on the IRIX version you plan to install. Up to Version 5.3, a
1.2GB harddisc should be enough, for IRIX 6.5 you really should
install at least a 2GB harddisc, better a 4GB harddisc.
5. Keyboard and Mouse
An annoying problem is that Indigos don't have PS/2 compatible
keyobards and mice, although the connector looks like it. So when
you want to buy an Indigo, you really should check that you also
receive a keyboard and mouse, or you wonÄt have much fun
with it, although it is possible to build a converter
to plug in normal PS/2 styled keyboards and mice.
6. Other Details of Interest
There are some other items you should check before buying a specific
Octane:
- What is the general cosmetic condition?
- Is the lockbar present? It prevents opening the case by unauthorized
people.
- Are keyboard and mouse included? Normal PS/2 styled keyboards
and mice won't work!
- Is IRIX installed, which version? Is it a clean install? Do
you also get the installation CDs?
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