The VMM passes the following parameters to the real-mode initialization procedure:
| Parameter | Description |
| AX | Specifies the version number of the virtual machine manager. The AH register contains the major version number, and the AL register contains the minor version number. | ||
| BX | Specifies the loading flags. This register contains one of the following values: | ||
| Value | Meaning | ||
| Duplicate_Device_ID | Device with same device identifier already loaded. | ||
| Duplicate_From_INT2F | Duplicate device identifier already loaded from Interrupt 2Fh device list. | ||
| Parameter | Description | ||
| Value | Meaning |
| Loading_From_INT2F | This device was specified in the Interrupt 2Fh device list. |
| ECX | Specifies the 32-bit address (segment:offset) of the entry point for real-mode initialization services. Virtual devices can call this address to retrieve settings from the SYSTEM.INI initialization file. This address is valid for VMM versions 3.10 or later. For more information about the services, see Section 3.9, “Real-Mode Initialization Services.” |
| EDX | Specifies a pointer to reference data provided in the Interrupt 2Fh. This register contains zero if there is no reference data. |
| SI | Specifies the segment address of the environment passed from MS-DOS. |
| SS:SP | Specifies the 32-bit address (segment:offset) of the stack. |