Appendix 3 - IOS Registration Flowchart

VOLTRK_

1. 
   Ignores if !(DCB_device_flags & DCB_DEV_REMOVABLE)
   
2. 
   Hooks if DCB_device_type is DCB_type_floppy
   
3. 
   Ignores if !(DCB_device_flags & DCB_DEV_LOGICAL)
   
4. 
   Hooks if DCB_device_type is DCB_type_disk or DCB_type_cdrom.
   

CLASS_ DRV_BIT

1. 
   Ignore if not (DCB_device_type == DCB_type_cdrom).
   
2. 
   Ignore if any of the following DCB_dmd_flags bits are set: (DCB_dmd_srb_cdb+DCB_dmd_rsrv_1+DCB_dmd_rsrv_2).
   

BIT

1. 
   Ignore if a logical DCB or if handled by rmm (if DCB_device_flags & (DCB_dev_logical | DCB_dev_rmm))
   
2. 
   Ignore if not a disk (DCB_device_type != DCB_type_disk)
   
3. 
   Ignore if not a floppy (DCB_device_type != DCB_type_floppy)
   
4. 
   Ignore if any of the following DCB_dmd_flags bits are set: (DCB_dmd_srb_cdb+DCB_dmd_rsrv_1+DCB_dmd_rsrv_2).
   

1. 
   Ignore if not a physical DCB
   (!(DCB_device_flags & DCB_dev_physical))
   
2. 
   Ignore if device doesn’t use the SCSI bus
   (DCB_Bus_Type != DCB_Bus_SCSI)
   

1. 
   Ignore if a logical DCB or if handled by rmm (if DCB_device_flags & (DCB_dev_logical | DCB_dev_rmm))
   
2. 
   Ignore if device doesn’t use the SCSI bus
   (DCB_Bus_Type != DCB_Bus_SCSI)
   
3. 
   Ignore if not a CD-ROM (DCB_device_type != DCB_Type_CDROM)
   
4. 
   Accept if device has been forced to use protected mode code or it is safe to use protected mode code. Ignore if MSCDEX is installed.
   

1. 
   Ignore if a logical DCB or if handled by rmm (if DCB_device_flags & (DCB_dev_logical | DCB_dev_rmm))
   
2. 
   Ignore if device doesn’t use the SCSI bus
   (DCB_Bus_Type != DCB_Bus_SCSI)
   
3. 
   Ignore if not a CD-ROM (DCB_device_type != DCB_Type_CDROM)
   
4. 
   (This VxD tweaks the CDB if the target device is an NEC ATAPI device).
   

1. 
   Ignore if a logical DCB or if handled by rmm (if DCB_device_flags & (DCB_dev_logical | DCB_dev_rmm))
   
2. 
   Ignore if device doesn’t use the SCSI bus
   (DCB_Bus_Type != DCB_Bus_SCSI)
   
3. 
   Ignore if not a disk (DCB_device_type != DCB_Type_disk)
   
4. 
   Accept if !(DCB_inquiry_flags.INQ_dev_type_mod & INQ_mod_removable).
   
5. 
   Otherwise, conditionally accept depending on manufacturer ID (Insite or IOMEGA floptical).
   

1. 
   Ignore if a logical DCB or if handled by rmm (if DCB_device_flags & (DCB_dev_logical | DCB_dev_rmm))
   
2. 
   Ignore if neither DCB_port_name == IDEATAPI, or DCB_device_flags2 == DCB_DEV2_ATAPI_DEVICE
   
3. 
   Ignore if not SCSI (DCB_Bus_Type != DCB_Bus_SCSI)
   
4. 
   Ignore if not CD-ROM (DCB_Device_Type!=DCB_Type_CDROM)
   
5. 
   Ignore if LUN=0 (if non zero, it’s a drive the atapi changer created)
   
6. 
   Issue a sense command to the CDROM to identify whether it is a changer; ignore if it isn’t.
   
7. 
   Otherwise take over the CDROM device.
   

1. 
   Ignore if a logical DCB or if handled by rmm (if DCB_device_flags & (DCB_dev_logical | DCB_dev_rmm))
   
2. 
   Ignore if device doesn’t use the SCSI bus
   (DCB_Bus_Type != DCB_Bus_SCSI)
   
3. 
   Ignore if not a CDROM (DCB_device_type != DCB_Type_CDROM)
   
4. 
   Check the dead_drive_table list. If in the list, and within the revision range specified, set DCB_cd_device_flags |= DCB_CD_FAKE_SCSI1. This will force a “bad” drive to use scsi1 behavior.
   
5. 
   Check the mfg_id_table. If in the table, or if the ANSI version field indicates it is a generic SCSI1 device ((DCB_inquiry_flags[2] & 0000111) < 2), accept it (take over the device).
   
6. 
   Note that when this driver intercepts requests, it will ignore IOR_SCSI_PASS_THROUGH IOP’s.
   

1. 
   Ignore if a logical DCB or if handled by rmm (if DCB_device_flags & (DCB_dev_logical | DCB_dev_rmm))
   
2. 
   Accept if (DCB_bus_type == DCB_BUS_ESDI) && (DCB_device_type == DCB_type_disk)), or if (DCB_device_flags2 & DCB_DEV2_ATAPI_DEVICE)
   
3. 
   Note that this VxD doesn’t “hook” into the calldown chain. It serves as a ring 3 interface (DeviceIoControl).