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The sad state of Alpha emulators (for OpenVMS)

Published: 30-04-2018 | Author: Remy van Elst | Text only version of this article

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(You can read all my OpenVMS articles by clicking the picture above)

OpenVMS 7.3 was the last version for the VAX architecture. All later versions(like 8.4) are only available for the Alpha CPU architecture or Intel's Itaniumplatform. Since I don't want hardware running, which is suprisingly hard to getin The Netherlands, Alpha machines, I want to be able to run it in an emulator.simh is the best open source VAX emulator, but it does not support Alpha. Myadventure with es40, the only open source Alpha emulator (development halted 10years ago) ended prematurely since it crashes all the time. The only otheravailable options are FreeAXP, Charon-AXP, vtAlpha and EmuVM AlphaVM. OnlyFreeAXP is available as a free (but not open source) download, Charon had apersonal version but that is nowhere to be found nowdays, vtAlpha has no freeversion or trial and EmuVM Alphaserver also stopped with their free version.

This article focusses on the hobbyist aspect of Alpha emulation. If you're acompany and spend a big sum of money, you will have all the resources you'llever need.

If you like this article, consider sponsoring me by trying out a Digital OceanVPS. With this link you'll get $100 credit for 60 days). (referral link)

Limits of commercial Alpha emulators

FreeAXP and AlphaVM offer a free or trial version of their product. FreeAXP iscompletely free to use (but doesn't work in my case) and AlphaVM offers alimited trial for a month.

AlphaVM used to offer a free version but they stopped doing that in 2015. Icontacted them and their CTO was quick and professional with his reply's. Hetold me that they stopped the free version because it was used commercially,thus hurting the sale of their commercial offering. If you're a serious hobbyisttheir product is available for $400, which, comparing the prices to Charon-AXPand Avanti (freeAXP's commercial counterpart) is very cheap. The CTO, ArtemAlimarin has, according to LinkedIn, also worked at Stromasys and createdCharon-AXP, so he knows Alpha emulation.

I was given a 30 day trial version of AlphaVM basic, with both a Windows andLinux version download. The product does require to be always online due to alicense check.

Charon-AXP has no trial version and they did not respond to my inquiries.vtAlpha same story, no trial or free version.

FreeAXP is limited to 1 instance with 128 MB RAM and emulates only anAlphaserver 400.

AlphaVM Basic is limited to 1 instance, 1 GB of RAM and it can emulate a rangeof Alpha systems.

Both AlphaVM and FreeAXP allow only 1 instance to be running. That limits youroptions to tinker with a cluster setup in OpenVMS. You could run multipleinstances FreeAXP on different hardware. EmuVM checks the license so thatdoesn't work.

Both FreeAXP and AlphaVM don't support Idle CPU. That means that when theemulated CPU has nothing to do, it will still use full resources on the hostmachine.

So if you want to cluster, you need to stick to simh and OpenVMS 7.3, or getyour hands on actual hardware.


I tried to install es40 on Ubuntu 16.04 and in that, install OpenVMS 8.4.That works up to halfway through the installer, then it crashes:

%SYSTEM-F-ACCVIO, access violation, reason mask=00, virtual address=FFFFFFFFFFFFFFB8, PC=000000007FDC5210, PS=0000001B  Improperly handled condition, image exit forced.

Even after multiple tries it crashes on different times during the install:

Exception in CPU thread: System exception: cannot signal semaphore: count would exceed maximum.Emulator Failure: Threading error: CPU thread has died: AlphaCPU.cpp, line 532Stop threads: cpu0 ali kbd ide0 ide1 srl0Freeing memory in use by system...pci0.15(ali_ide).disk0.0(file): Closing file.*** Error in `es40': double free or corruption (fasttop): 0x0000000001886fe0 ***

No luck there. There are no other open source Alpha emulators.


FreeAXP is a free Avanti virtual Alpha technology demonstrator. It provides avirtual AlphaServer 400 equipped with 1 CPU, 128MB memory, 7 disk drives, twoNICs, and two virtual serial ports.

I downloaded version on Windows 10 x64 (1709 build 16299.125).Installation was a breeze and the first try worked as well, I was able toinstall OpenVMS 8.4. The next try, actually running OpenVMS, fails horribly. Thesoftware crashes after loading the config file, and even killing the process viathe task manager fails:


That adventure ended way to quickly. There is a topic here on os.comp.vmswhere this issue is discussed, but sadly without a fix yet. Downgrading winPCAPhad no effect for me.

EmuVM basic

I was given a trial of EmuVM's AlphaVM Basic, which will function for 1 month.It runs both on Windows and on linux (without GUI). Here is a picture of theWindows version:


I experienced no problems at all, the installation went without issues andsubsequent starts all went fine.

The Linux version of AlphaVM has no GUI. Using the Windows GUI and the option"View config as text" I was able to generate my configuration to use on Ubuntu16.04. The Debian 7 .deb package installed and it all worked as expected thereas well. I did have to change filesystem paths on Linux and I removed mostoptions that looked liken they came from Windows. Disks on Linux can be createdwith dd and in Windows they provide a tool.

Here is a screenshot of the Linux version:



The only free option available is FreeAXP, but that is not available for Linuxand the Windows version doesn't work for me.

The only working option is EmuVM's AlphaVM, which for me works both on Windowsand on Linux without issues. The customer support is good and the product isfeaturefull.

If I ever would have to do a commercial OpenVMS deployment on Alpha, based on myexperience now I would let the company buy the AlphaVM Pro version. That doesnot require an always online license check but a USB dongle or special hardwarebind (also for virtual machines).

I do hope that EmuVM rethink their free offering. I suggested not to limit onemulated hardware like FreeAXP, but to just let the product run for two hoursand then force five hours of pause until it can run again. No commercial use canbe done in only two hours I guess. For hobbyist use it is fine however, in twohours I can tinker a fair amount. I do hope it does not require always connectedlicensing checks, since my tinkering often happens on systems without internetconnection. Or, imagine the case that in 10 years I want to play again and theirlicense server is not available anymore.

The other option is to get hold of actual Alpha hardware and install OpenVMSthere. No limits and clustering is only limited how much hardware you can getyour hands on. But, old hardware is hard to maintain and it won't get newer orcheaper.

So the state of Alpha emulation for OpenVMS in 2018 for hobbyists is poor. Let'shope VSI release a hobbyist version of the OpenVMS x86 release they are making.Then I can just use KVMN or Virtualbox to play with OpenVMS.

Tags: alpha, blog, dec, decus, es40, itanium, openvms, pdp, simh, vax, vms