Virtual Alpha Base Settings covering memory, JIT, Auto-Exit NVRAM, and TOY settings.

Main Memory

Main memory defines the amount of memory assigned to the virtual Alpha system.  Available memory is selected from a drop-down list.

Avanti supports configuring 32MB to 3GB of main memory regardless of the guest operating system. Digital UNIX and Tru64 UNIX can use up to 1GB; this guest limit does not reduce the emulator's 3GB configuration capacity.  A zero-unit configuration includes up to 128MB, and larger selections require the license-unit count shown below. Units are based on configured memory, not the amount the guest can use.  Memory is mapped to match the three memory banks available in a real AlphaServer 400.  The user need only specify the total memory desired in the Memory field.

A hand-edited main-memory value must be between 32MB and 3GB inclusive and must be an exact multiple of 16MB.  Numeric values contain one or more decimal digits and may have a K, M, G, or T suffix; memory suffixes use powers of 1024.  Suffixed terms may be concatenated, so 1G512M means 1536MB.  The configuration-file reader removes whitespace outside quoted strings before interpreting values; for example, an unquoted 1 2 8 M is read as 128M. Whitespace inside quoted numeric values, signs, bare or consecutive suffixes, trailing text, and values that overflow the supported numeric range are rejected.

Attempting to run a configuration with more memory than the installed key permits results in a license error.

JIT

Checking the JIT box enables Just-In-Time compilation. JIT is a performance enhancement that requires 60 license units. Attempting to run JIT without enough units results in a license error.

Auto-Exit

If checked, upon a normal OpenVMS or Tru64 UNIX shutdown, the emulator will terminate completely instead of stopping at the firmware prompt (>>>). Historical OpenVMS guidance uses Ctrl-P from the console session to interrupt a running guest and return to SRM; that path has not been revalidated for 5.1.0, so use it only with console access and confirm that the SRM prompt is visible before entering firmware commands. Under Tru64 UNIX, init 0 initiates the guest shutdown; with Auto-Exit enabled, the emulator can then terminate rather than remain at SRM.

Versions of Avanti prior to version 4.0.0 do not support the Auto-Exit feature. Remove Auto-Exit from the Avanti configuration before running an older Avanti version.

Auto-Idle

By default, Avanti utilizes one host CPU running at 100% to emulate the Avanti Alpha CPU.

With the Auto-Idle option selected, Avanti will idle the host CPU when the guest Tru64 UNIX or OpenVMS O/S is not busy.

Auto-Idle is not enabled by default. The Auto-Idle check box must be selected in the Avanti configuration file to enable the Auto-Idle feature

Some existing OpenVMS systems contain third-party Charon or HP Idle utilities. Avanti does not distribute or qualify a particular version of those utilities for 5.1.0. Do not enable Auto-Idle and a guest idle utility together unless that exact combination has been tested; remove or disable the guest utility before selecting Auto-Idle for a new configuration.

Auto-Idle changes how the emulator waits when it recognizes a guest idle loop. The result depends on the guest and workload. If enabling it causes unacceptable I/O latency or performance degradation, clear the option and restart Avanti.