Core Devices
Table of Contents
CPU
ace_mode
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 | ace_mode |
|---|---|
Type | Boolean |
Value | 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=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.
RAM
The CHARON-VAX memory subsystem is permanently loaded and has the logical name "ram".
size
Parameter | size |
|---|---|
Type | Numeric |
Value | Size of emulated memory in MB. |
Example:
|
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 |