Core Devices

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CPU 

A CHARON-AXP emulated CPU is configured with the "ace_mode" parameter enabling the high performance Advanced CPU Emulation mode ("ACE"). The ACE option optimizes the HP Alpha instruction interpretation and significantly improves performance. It also requires approximately twice the amount of host memory to store the optimized code.

ACE optimization is performed dynamically during execution. It does not need to write optimized code back to disk, ACE provides its full capability instantly. The optimization does not compromise the HP Alpha instruction decoding; CHARON-AXP remains fully HP Alpha hardware compatible and completely transparent to the HP Alpha operating systems and applications.

Example:

The amount of memory is capped at a maximum, this is defined in the CHARON license key. If the host system cannot allocate enough memory to map the requested emulated memory, CHARON-AXP generates an error message in the log file and reduces its effective memory size.

The following table lists the values of emulated RAM for various hardware models of virtual HP Alpha systems:

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TOY

CHARON-AXP maintains its time and date using the "toy" (time-of-year) component. In order to preserve the time and date while a virtual system is not running, the TOY component uses a binary file on the host system to store the date and time relevant data. The name of the file is specified by the “container” option of the "toy" component.

Example:

The CHARON-AXP time zone may be different from that of the host system. Correct CHARON time relies on the correctness of the host system time to calculate the duration of any CHARON “offline” periods. (i.e. while the virtual system is not running). Every time CHARON comes on line it calculates a Delta time (the system time is used if there is no TOY file). Therefore, if the host system time is changed while CHARON is not running, the CHARON time may be incorrect when CHARON is restarted and the CHARON time must be set manually.

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ROM

The System Flash ROM file conserves specific parameters between reboots.

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Virtual HP Alpha interval timer

The CHARON-AXP  provides interval timer interrupts to virtual Alpha CPU(s) at frequency 100Hz (100 interrupts a second).

This is default behavior which may be changed through “clock_period” configuration parameter of virtual ISA or EISA bus, depending on emulated hardware model of virtual HP Alpha system.

Value of the parameter is interval timer period in microseconds. By default it is set to 10000. By changing it to 1000 frequency of virtual interval timer interrupts may be increased to 1000Hz (1000 interrupts per second).

Example for AlphaServer 400, DS, ES, GS:

Example for AlphaServer 800, 1000, 1000A, 1200, 2000, 2100, 4000, 4100:

 Higher interval timer frequency creates higher load for virtual Alpha CPU which may cause degradation of overall virtual system performance.

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Setting of a particular HP Alpha model

It is important to have the "system_name", "hw_model", "cpu_architecture" and "dsrdb[0]" (DSRB - Dynamic System Recognition Data Block) parameters in sync. (see above for details) to configure CHARON-AXP to for emulation of a particular HP Alpha model.

The following table illustrates how to synchronize those values:

HP AlphaStation 200 - 400

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HP AlphaServer 600 - 800

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HP AlphaServer 1000

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HP AlphaServer 1000A

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HP AlphaServer 1200 and AlphaStation 1200

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HP AlphaServer 2000

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HP AlphaServer 2100

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HP AlphaServer 4000

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Auto Boot

CHARON-AXP systems can be configured to boot the operating system automatically at start up.

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