Frequently Asked Questions

General questions

CPU

Serial lines

Disks and CD/DVD drives

Tapes

Network


Answers

Can I run multiple instances of AlphaVM on one machine?

Yes, you can. You have to set separate configurations in separate directories for all your instances. Additionally, you have to set the host CPU affinity for each instance. Consult the user manual for the details.

What is the difference between AlphaVM-Pro and AlphaVM-Free?

The main differences are:

Can AlphaVM release the host CPU when OpenVMS/Tru64 is idle?

This is possible with AlphaVM-Pro in JIT2 mode. Since the version 1.5.6 it is also available in all JIT modes. Enable Idle option in JIT configuration. Currently it is supported for a subset of guest OSes: most of supported OpenVMS version and Tru64 5.1b.

Does AlphaVM run on VMware?

AlphaVM is supported on VMware ESXi 5.x, VMware Workstation, and VMware Player. Refer here for the details. Please note that extra virtualization level can cause a noticable performance penalty.

Does AlphaVM run on Hyper-V?

AlphaVM is supported on Hyper-V. Refer here for the details. Please note that extra virtualization level can cause a noticable performance penalty.

Does AlphaVM run on VirtualBox?

It is not officially supported. VirtualBox incorrectly passes the host CPU capability flags. AlphaVM will not run with the flags passed by default. The flags can be corrected by the following command run from the Windows command prompt:

 "C:\Program Files\Oracle\VirtualBox\VBoxManage" setextradata AlphaVM VBoxInternal/CPUM/CMPXCHG16B 1
Here AlphaVM is the name of the virtual appliance to be changed.

Does AlphaVM run on Proxmox VE?

AlphaVM is reported to run in this environment. We do not officially support it. Please note that extra virtualization level can cause a noticable performance penalty.

Shall I chose Windows, Linux or FreeBSD as the host system?

We support all these systems to give you a choice. It does not matter much what you chose, because when you work with the emulated Alpha, it hardly makes a differece what OS is hosting the emulator. We advise to chose the OS you have more confidence with.

There is one difference to consider. The Windows version currently has a grahic user interface, whereas Linux and FreeBSD versions do not have it. On Linux and FreeBSD the AlphaVM can be lauched only from the command line. On Windows the Launcher GUI manages the configuration and the startup of the emulator in a convenient way.

Does OpenVMS run on AlphaVM?

Yes, AlphaVM is designed to run OpenVMS. Currently the supported versions are 7.1-2 - 8.4.

Does Digital UNIX/Tru64 run on AlphaVM?

Yes, AlphaVM is designed to run Tru64. Currently the supported versions are 4.0e - 5.1b.

Does Linux run on AlphaVM?

Yes, some Linux versions are tested and run on AlphaVM, although we do not officially support it. We tested with debian 5.0.6 and 5.0.8.

How do I copy my OpenVMS/Tru64 server disks to use with AlphaVM?

The simplest way is to use Gentoo Alpha LiveCD to boot your Alpha from it and to copy the disk images. The basic idea is that you boot from the CD and use DD and network to copy your disks to a location available via SSH. See the article Simple OpenVMS migration for the details.

How do I migrate my OpenVMS server to AlphaVM?

The article Simple OpenVMS migration describes a simple environment migration. Contact us or our partners for an advise about a complex environment migration.

May AlphaVM-Free be used for commercial purposes?

No, AlphaVM-Free is licensed only for non-commercial purposes. Please consider purchasing AlphaVM-Pro, if you need to use AlphaVM for commercial purposes. Contact us about AlphaVM-Pro pricing.

Does AlphaVM support multi-processor configurations?

Yes, it does. AlphaVM supports as much CPUs as the emulated chipset. At this point the maximum is 4. AlphaVM-Free is limited to single CPU.

What does JIT mean with respect to the CPU?

JIT stands for Just in time. The term comes from Java-like languages where Just-in-time compilation refers to a compilation technique when the code is compiled at runtime when it is first needed. AlphaVM uses similar technology to create fast native code for Alpha code pages.

What is the difference between basic, JIT1 and JIT2 CPUs?

Basic CPU is just an interpreter. It interprets Alpha code in a simple instruction loop. Each iteration fetches an opcode, dispatches to the corresponding habdler and executes the instruction handling code. Basic CPU is slow, which is an inherent property of an interpreter. JIT1 and JIT2 create native code for the Alpha code pages. The resulting code is faster. JIT1 is a simple compiler. It creates code, whose speed is approximately a double of the basic CPU speed. JIT2 is a very fast CPU, which is 10 or more times faster than the basic CPU.

How are the AlphaVM CPUs (basic, JIT1 and JIT2) related to the real Alpha CPUs (EV4, EV5, EV6, EV7)?

There are two aspects: instruction subset support and performance. All AlphaVM implementations support all instruction subsets. With respect to speed, the AlphaVM JIT2 CPU corresponds to EV6 and EV7 range. The other two CPUs are in EV4 range. The AlphaVM performance highly depends on the host hardware. So, there is no direct correspondance with the real ALpha CPUs. To keep these things clear, we have not called our CPUs after the EV4, EV5, EV6 and EV7.

What is about synchronous vs. asynchronous JIT?

By default JIT is asynchonous. It means that the CPU interprets Alpha code when there is no compiled version of it. At the same time the JIT compiler compiles the code in case it is needed next time. Synchronous JIT would compile first and then execute. There is no parallelism in it. Synchronous JIT is there merely for testing. There exist applications that constantly modify or generate code. Synchronous JIT is very inefficient with such applications, due to the compilation overhead for the code that is executed once. However, in some cases synchronous JIT is somewhat faster than asynchronous one, because it does not suffer from the synchronization overhead.

How fast is AlphaVM CPU?

AlphaVM-Free performs as a slow EV4 system. AlphaVM-Pro in JIT2 mode on a modern and powerful host can be as fast as EV7. Check the benchmarks page for more information about AlphaVM performacnce.

AlphaVM alsways consumes 100% of the host CPU core, even if my OpenVMS/Tru64 is idle. Can AlphaVM release CPU on idle?

AlphaVM-Pro can release the host CPU when the guest OS is idle. Just turn on the CPU idle option, which is off by default. In AlphaVM-Free this feature is not available.

Can I use a terminal emulator other than PuTTY?

Yes, you can configure a terminal emulator to use in the configuration property sheets for serial ports.

Can I connect the emulated serial line to a real serial line?

Yes, since 1.4.8 you can connect to a real serial line. This option is only available in AlphaVM-Pro.

Can I connect a real VT100 terminal to the emulator?

Yes, since 1.4.8 you can connect to a real serial line. This option is only available in AlphaVM-Pro. VT100 can be connected to the serial line of your host comuter.

Why does my terminal print characters double?

You should configure PuTTY for RAW mode and set LOCAL ECHO and LOCAL LINE EDITING to FORCED OFF.

What is a disk image?

Disk image is a copy of entire disk to a file. This copy can be obtained using special disk duplication tools, like Unix dd. There are also so called ISO images, which are images of CD/DVD/BR disks.

How do I create a disk image?

On Windows the GUI "Tools" menu has "Create disk image". In the dialog box you can select the type of a disk to create. On Linux use mkdisk script provided in AlphaVM package. Run the utility with -h option to see the usage.

How do I install OpenVMS or Tru64 from a CD?

It is advised to use an ISO image instead of a real CD. On Windows you can access the real CD by a name like "\\.\Cdrom0". On Linux it is usually /dev/cdrom.

  1. Add CDROM to the configuration, set its SCSI BUS, SCSI ID and the file/device name.
  2. Refer to the user manual for details.
  3. Run the VM. It will show the SRM console prompt >>>.
  4. In that console prompt you can type commands like "show dev" to see what devices are seen by the VM.
  5. Determine your CDROM device name and run a boot commands like "boot dka400". The system will boot from CD. The device name depends on the selected SCSI BUS and the SCSI ID of the CDROM device.

How do I change a virtual CD medium (a CD image)?

Currently there is no "button" to eject or load virtual CD media. However, you can eject/load the media issuing a SCSI commmand.

On OpenVMS you can use the RZT tools for it. First define the symbol:

rzt:==$sys$etc:rztools_alpha
Unload the CD:
rzt dka400 /stop
Load the CD:
rzt dka400 /start
On Tru64 you can eject the CD as follows:
scu -f /dev/rdisk/cdrom0c eject
Currently you cannot specify another CD image name of the fly. However, you can put another image in the file with the same name and mount it again. The virtual medium is loaded automatically, if the file is present.

Does AlphaVM support FibreChannel storage?

No, currently not.As a workaround you can migrate to shared SCSI disks images on the AlphaVM level (on VMS).The disk images can reside on FibreChannel disks provided by the host system.

Can I use iSCSI disks?

In AlphaVM-Pro (since 1.4.2) you can. Just use the SCSI Pass Through feature to access the disk device. On Windows the device is called something like \\\.\PhysicalDrive3. On Linux the devices are called /dev/sg*.

Can I use a real tape drive with AlphaVM?

In AlphaVM-Pro (since 1.4.2), you can. Connect the tape by means of SCSI Pass Through feature. Note that SCSI Pass Through is only available in the professional version.

What is a virtual tape?

Virtual tape is a an emulated tape drive which stores data in a file. Such a file is called a virtual tape image. The tape image format is compatible with SIMH.

Why does the real tape give the error BACKUP-F-NOTANSI?

It seems that there is a problem with the host SCSI Controller LSI Ultra320. Please use another controller for SCSI Pass Through. It was successfully tested with LSI 53C8xx and with Adaptec SCSI controllers.

10Mbit connection speed is reported by OpenVMS/Tru64. Can it be faster?

The is a reported link speed. It does not mean that the actual data transfers happen at 10 megabits/sec. The actual data transfer always happens at the maximal speed. Thus, at 1Gbit network the actual transfer happens at 1Gbit.

You can load a 100Mbit adapter (DE500) instead of the default DE435. In that case the speed of 100Mbit will be reported.However, this is unlikely to have an effect on the real transfer speed.

Why does AlphaVM get SIGSEGV on Linux during boot, when network is configured?

It is likely that you have not enabled the capabilities to access raw ethernet in non-root mode. See the user manual about setting the capabilities.

Can I connect between AlphaVM guest OS and the host computer?

Yes, you can. However, you need some bridge magic or a dedicated network interface to be able do it. Please refer to the user manual.

Why does not network work on VMware?

On VMware (running on bare hardware) a NIC cannot be shared between the host OS (Linux, Windows) and the AlphaVM guest OS. You need to create a dedicated VMware NIC for each AlphaVM NIC. More information is available here.