Introduction to Alpha Hardware Virtualization Prepare text for printer


Alpha Hardware Virtualization allows users of HP Alpha computers to move their application software and user data to a non-Alpha platform without having to make changes to their software and data. Alpha Hardware Virtualization is a software solution that replaces Alpha hardware.

This approach is best understood when you view the Alpha Hardware Virtualization Software as a special interface between the old Alpha software and a new hardware platform. Simply spoken it presents the Alpha hardware interface to the original Alpha software, so the existing software will not notice a difference.
This means no changes at all have to be applied to the existing software. Your user programs and data can be copied to a new platform and run for many more years. Replace your Alpha system by a combination of a general purpose computer (64 bit Intel or AMD) and our Hardware Virtualization Software.

The Alpha virtualization software is designed to replace single and multi CPU Alpha computer systems, like:

  • DEC3000 AXP (model 300, 400, 500, 600, 700 and 800)
  • AlphaServer 300
  • AlphaServer 400
  • AlphaServer 800
  • AlphaServer 1000
  • AlphaServer 1200
  • AlphaServer 2000
  • AlphaServer 2100
  • AlphaServer 4000
  • AlphaServer 4100
  • AlphaStation 200
  • AlphaStation 250
  • AlphaStation 500
  • AlphaStation 600
  • AlphaStation XP900
  • AlphaStation XP1000

The principles of Alpha Hardware Virtualization

In order to make correct decisions regarding how to apply Alpha Hardware Virtualization or Emulation it is important to make a distinction between the Alpha hardware that is virtualized or emulated and the (non-Alpha) hardware from the host platform that carries de Alpha Virtualization Software.

Virtualized hardware:

CHARON-AXP virtualizes various Alpha architectures and can meet the performance level of these Alpha's when run on the hardware platform we advise for these systems. Our Alpha emulator product is currently available in the following variants:

  • CHARON-AXP/3000 to replace DEC3000 AXP systems
  • CHARON-AXP/SMA to replace lower-end Alpha Servers (AlphaServer 300, 400, 1000, 2000)
  • CHARON-AXP/SMA+ to replace mid-range Alpha systems (AlphaServer 800, 4000, 4100 and AlphaStation 500/600, DPW, XP900, XP1000)

The original Alpha systems supported a family of adapter boards and it is sufficient to virtualize one of these family members to cover the whole range. In such a family line you will often find performance or functionality improvements that were typically hardware bound. By emulating only one (often the last) occurrence Virtualization of the older hardware models is often automatically invoked. For example: by emulating the KZPBA UltraSCSI adapter we include support for the earlier models KZPAA (single ended) and KZPSA (FWD) and multiport models (KZPAC) and even a combo board like the KZPCM (SCSI and Ethernet combined).

The following table explains which hardware item we virtualize and which other adapters are covered by it:

Emulated hardware Covers Alpha hardware
KZPBA SCSI adapter KZPAA, KZPSA, KZPBA, KZPAC, KZPSC, KZPCM (SCSI part only)
DE500 Ethernet adapter DE205, DE425, DE450, DE500, DE600, DE504 (4 ports)
PBXDA Serial lines adapter PBXDA, CXI01
RZ-type SCSI disks All SCSI disks as logical or physical disk *)
Tape DAT and DLT

*) note that CHARON-AXP release 2.0 and newer support the use of DSSI, MSCP and FibreChannel disk identifyers (e.g. DIA, DGA) when running OpenVMS and the special configuration option for this feature. View the configuration section for more details about this capability.

Host platform

The Virtualization Software presents the Alpha operating system with typical Alpha devices allowing it to function as were it still running on an Alpha computer. While emulating SCSI disks attached to a SCSI adapter they could show up as container files on any disk type of the host platform or as a physical windows drive. This diagram explains that what for the Alpha appears to be physical disk can be translated to disk container files on a Windows disk, or can be represented to what the host operating system sees as a physical disk or to a direct addressed (i)SCSI disk device.

With the use of current storage technology disks do not have to be physically attached to the Host platform, but they can reside on a SAN or iSCSI storage structure.

A similar translation process is also valid for other emulated hardware devices.