My Computer Collection
DECpc AXP/150

Photo of DECpc AXP/150
Click here or click onto the photo for a full size version of this picture.

The DECpc 150/AXP was the first 'Alpha PC' produced by Digital. The idea behind them was to make an Alpha system with a PC-like peripheral environment, thereby allowing to use as much cheap PC hardware as possible. DEC's primary intent was to run Windows NT, and this machine was sold with a preinstalled NT 3.1 via Vobis, Germany's largest computer seller. It was a great flop, given that the NT 3.1 this machine was sold with was the first Alpha version of NT that still consisted mostly of i386 code, so the processor spent most of the time emulating an Intel CPU. Selling it with only 16 Mbytes of RAM didn't make the situation better...

The system board in this machine is also known as the 'Jensen' board, and this also gave the machine its nickname. Depending if you bought one from DEC with NT or Unix/VMS preinstalled, the machine was labelled either 'DECpc AXP/150' or 'DEC 2000 Model 300'.

However, the AXP/150 was the first Alpha machine Linux was ported to, and with at least 32 Megs, this machine is still a performer, especially for floating-point hardware. If you get such a machine without any EISA cards, you will probably have a hard time getting it to work: The AXP/150's console only supports booting from a AHA1742A (the version with two EPROMs!!), and not all VGA boards work (the SRM console needed to boot Linux cannot use the card's BIOS to correctly initialize the specific chip). If you have an Elsa Winner 1000 TwinBus like me, be sure not to upgrade to a firmware later than 1.7!

As I said on the main page, I have two Jensens; don't they make a beautiful pair? Since one of them also acts as a printer server, it seemed a good idea to use them as a printer stand for my laser printer. In fact, the Jensen's case is so massive that you can sit on it...

Photo of innards of DECpc AXP/150
Click here or click onto the photo for a full size version of this picture.

The look into the case of an AXP/150 is a fine example for how a computer can be built if the designers don't have to optimize it to be as cheap as possible :-) Notice the large fan that cools both the CPU and EISA cards. This eliminates the need for one of those tiny CPU fans directly screwed onto the CPU cooler which seem to have an average MTBF of half a year. Moreover, this fan is temperature-controlled and can therefore rotate at a far lower speed with its larger volume, making it even more silent.

DECchip 21064, 150 MHz
integrated into CPU
8 Kbytes Code, 8 Kbytes Data
512 Kbytes
Integer Performance:
roughly like a Pentium 90
80 Mbytes (options range from 16M to 128M)
6 EISA slots
Interfaces (onboard):
  • Mouse, Keyboard
  • 2 x Serial
  • Parallel
Add-on cards:
  • Elsa Winner 1000 TwinBus, 2 Mbytes
  • Adaptec AHA1742A SCSI host adapter with floppy interface
  • 3COM Etherlink/2 (3C503/16) 10Mbps Ethernet Adapter
  • 3COM Etherlink/3 EISA (3C579) 10Mbps Ethernet Adapter
Operating System(s):
  • Redhat Linux 5.0 with 2.1 kernel

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©1998 Alfred Arnold,