9. Jensen (DEC 2000/DECpc 150/Highscreen AXP)
Contents of this section
Please send comments about this section to Martin Ostermann (
ost@comnets.rwth-aachen.de
).
The Jensen was the first Alpha PC that has been available
commercially from DEC. Not surprisingly, there are a few oddities
with it. This section is an attempt to help people getting
Linux/Alpha installed on a Jensen, and to provide additional
information operating Linux on the Jensen.
9.1 Installation
First off, there is no MILO for the Jensen. So it is unavoidable to
use Jensen's builtin SRM console. Unfortunately, it is severely
handicapped with respect to boot command line option processing.
Thanks to
Michael Schwingen
there is now a new
aboot
loader that can work around these limitations.
Secondly, the Jensen SRM console cannot boot from a floppy. This used
to make bootstrapping Linux a real pain, until
Jim Paradis
contributed a minlabel and
writeboot programs executable from the ARC console. These are
available together with a the JENSEN-HOWTO describing the installation
process in detail in the
JENSEN_INSTALL
document. Another version, which you probably want to use, includes a
pre-compiled aboot loader and updated installation instructions and is
available
here
.
The Jensen is supported by
Red Hat Linux
and BLADE_0.2. BLADE_0.2 is heavily
outdated nowadays, and you certainly don't want to install it. Last
time I checked,
Craftworks Linux
did not support the Jensen
officially. It might work with another kernel image, though.
Anyhow, even with Red Hat Linux you need to get your X Server
seperatly, see below.
9.2 The Jensen is different
The Jensen differs from other systems in several ways:
- MILO. It was already stated that there is no Milo for the Jensen. This is
because the firmware implementation of the Jensen differs somewhat
from the one on other systems. PALcode is the keyword to look for, if
your interested to know more.
- EISA-Bus. The Jensen only got an EISA bus, no
PCI. Furthermore, it uses a very special addressing scheme for the
bus. While the kernel usually takes care of that in respect to device
drivers, it has to be taken care of by utilities that do i/o in user
space, like the X servers. Therefore there is a special X server for
the Jensen, This server, which supports
only S3 based cards, is available from
Martin Ostermann's Alpha Page
.
There is a different (older) version by Stephan Kanthak available via ftp
from
AZStarNet
. You'll also find
other useful stuff there, like a ported SVGAlib.
If you're interested in details, watch for the keywords SPARSE vs
DENSE memory.
- RTC. Somehow it was managed to locate the real time clock
at a different place (I/O port 0x170 instead of 0x70 on all other
machines). Thus the original clock program will fail. A patched
version is available from
Martin Ostermann's Alpha Page
.
- Firmware. Since the Jensen is the oldest machine around,
there are chances that you got a very old firmware. The date format
changed in newer version, which will cause an offset of 20 years. You
ought to get a
firmware update
. WARNING: If you own an ELSA-Winner 1000
graphics adapter, don't update beyond version 1.7! Otherwise you'll
not be able to use your card in EISA mode. This is probably due to a
bug in the EISA BIOS of the card.
9.3 Known Problems
Know Problem and workarounds:
- Date and Time. Due to the location of the real time clock
and/or an old firmware. See above.
- Won't boot after firmware update. Aboot-0.3 doesn't work with
new firmwares. It is known to work with versions up to 1.7.
If you own an
ELSA-Winner 1000 graphics adapter and upgraded beyond firmware
version 1.7, the card won't work in EISA mode. Turn the card, so that
it is plugged in with its ISA side.
Maybe you want to downgrade you
firmware again. (Windows-NT 3.51 seems to work fine with firmware 1.7) The
problem is, that the older firmware versions are
not available via FTP from Digital. If you only got the choice between
an very old and a recent one, try to contact your local Digital
representative.
- aboot-0.x doesn't compile on recent kernels.
Get aboot-0.4, it works with recent kernels.
- Won't automatic reboot after correct shutdown. Known
problem, no solution available so far. On some machines, you even
cannot boot by hand, but you have to power-cycle.
9.4 Miscellaneous Information
So what is the Jensen all about? There is a some information
available online:
- The Evolution of the Alpha AXP PC (
text
/
Postscript
)
by David G. Conroy, Thomas E. Kopec, and Joseph R. Falcone.
This describes the development leading to the Jensen system.
- Product announcement and description (
text
/
Postscript
) by Digital. This is
an overview of the Jensen system components and options.
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