Core Devices

CPU

The CHARON-VAX emulated CPU is configured with the "ace_mode" parameter.

Two VAX CPU implementations are available: the standard VAX instruction decoder and the optional high performance Advanced CPU Emulation mode ("ACE"). The ACE option optimizes VAX instruction interpretation and significantly improves performance. It also requires approximately twice the host memory to store the optimized code.

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

Both CPU implementations passed the HP VAX Architecture (AXE) tests, the standard qualification for VAX instruction execution correctness.

The default VAX CPU mode is determined by the specific CHARON-VAX product license.

Parameter	Type	Values
ace_mode	Boolean	true or false.

This statement enables ACE mode if the CHARON-VAX license permits it. If this statement is omitted from the CHARON-VAX configuration file and the license permits it, "true" is the default. Otherwise "false" is the default. For test purposes the ACE mechanism can be disabled with:

set cpu ace_mode=false

"set cpu ace_mode=true" is ignored when the license does not permit ACE operation.

The CHARON-VAX log file displays the status of the ACE option.ACE mode is disabled when the host system does not meet the minimum physical requirements for operation. If the emulator appears not to run at its normal performance, check the log file for a change in ACE mode and verify that sufficient host resources, especially memory, are available.Back to Table of Contents

RAM

The CHARON-VAX memory subsystem is permanently loaded and has the logical name "ram".

Parameter	Type	Description
size	Numeric	Size of emulated memory in MB.

Example:

set ram size = 512

The amount of memory is capped at a maximum, defined in the CHARON license key. If the host system cannot allocate enough memory to map the requested emulated memory, CHARON-VAX 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 VAX systems:

Hardware Model	RAM size (in MB)
	Min	Max	Default	Increment
MicroVAX_II	1	16	16	1,8,16
MicroVAX_3600	16	64	16	16
MicroVAX_3900	16	64	16	16
VAXserver_3600	16	64	16	16
VAXserver_3900	16	64	16	16
VAXserver_3600_128	32	128	32	32
VAXserver_3900_128	32	128	32	32
MicroVAX_3100_Model_96	16	128	16	16
VAXstation_4000_Model_90	16	128	16	16
VAX_4000_Model_106	16	128	16	16
VAX_6000_Model_310	32	512	32	32
VAXserver_3600_512	32	512	32	32
VAXserver_3900_512	32	512	32	32
MicroVAX_3100_Model_98	16	512	16	16
VAX_4000_Model_108	16	512	16	16
VAX_4000_Model_700	64	512	64	64
VAX_4000_Model_705	64	512	64	64
VAX_6610	128	3584	128	128
VAX_6620	128	3584	128	128
VAX_6630	128	3584	128	128
VAX_6640	128	3584	128	128
VAX_6650	128	3584	128	128
VAX_6660	128	3584	128	128

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TOY

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

Parameter	Type	Description
container	Text string	Specifies a name of a file in which CHARON-VAX preserves time and date during its “offline” period. This file also keeps some console parameters (such as default boot device)By default it is left unspecified. it is recommended to specify the full path to the file

Example:

set toy container="/path/my_virtual_system.dat"

The CHARON-VAX 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 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.Back to Table of Contents

ROM

The System Flash ROM file conserves specific parameters between reboots.

Parameter	Type	Description
container	Text string	Specifies the name of a file in which CHARON-VAX stores an intermediate state of its Flash ROM. This state includes, for example, most of the console parameters.By default it is left unspecified. it is recommended to specify the full path to the file

Example:

set rom container=”/path/my_virtual_system.rom”

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EEPROM

Parameter Type Value

container

Text string

A string specifying a file name to store content of EEPROM.Example:

set eeprom container="vx6k610.rom"

This command enables EEPROM parameters (e.g., default boot drive) to be automatically saved to a specified file. The EEPROM file is created in the directory in which CHARON-VAX starts. The EEPROM file is created or overwritten each time any parameter relevant to EEPROM content is changed.

Example:

set eeprom container=”/path/my_virtual_system.rom”

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Auto boot

CHARON-VAX systems may be configured to boot the operating system automatically at start up.

MicroVAX3100, VAXstation 4000, VAX6310 and VAX 4000

Those models boot automatically if correct boot flags are set (and saved in the VAX console files) using the following command:

Console Parameter Description

halt

Determines whether the MicroVAX3100, VAXstation 4000, VAX6310 and VAX 4000 boot automatically if correct boot flags are set (and saved in the VAX console files).The value is:

"reboot"

Example:

>>>set halt reboot

Please check that the "toy container" and "rom container" parameters are specified in the configuration file to store the boot flags.

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MicroVAX II, MicroVAX 3600/3900 and VAXserver 3600/3900

The ROM of the MicroVAX II, MicroVAX 3600, MicroVAX 3900, VAXserver 3600 and VAXserver 3900 does not allow the VAX console to accept the command setting "auto-boot". Instead, automatic boot on startup can be specified in the CHARON-VAX configuration file as follows:

Parameters Type Value

bdr boot

Text string

Determines whether the MicroVAX II, MicroVAX 3600, MicroVAX 3900, VAXserver 3600 and VAXserver 3900 boot automatically if correct boot flags are set (and saved in the VAX console files).The value is: