Removal Scenarios for Devices
Removal-related device capabilities that are relevant to this include SurpriseRemovalOK and Removable.
1.Removable. This capability is set by the bus driver for the bus on which a given device is installed.
2.SurpriseRemovalOK. This capability is set by the driver for the device. It specifies whether the device can be safely removed without using the Safely Remove Hardware applet.
3.If both Removable and SurpriseRemovalOK are set, the device can be removed without using the applet. If Removable is TRUE, the device is displayed in the Safely Remove Hardware applet unless SurpriseRemovalOK is also set to TRUE.
Windows XP has the following removal policy options:
The operating system uses the following algorithm to determine removal policy defaults:
1.The bus driver sets the Removable device capability according to the operating system default for the device. ACPI BIOS can override the Removable capability by using the _RMV method.
2.If the device is determined to be removable, the operating system checks to see if there is an INF override for removal policy.
3.If no INF override is provided, Windows checks IEEE 1394 devices for any override value in the configuration ROM.
4.In the absence of either an INF or hardware override, Windows bases the removal policy on the bus of the removable device. USB,IEEE1394,PCMCIA---ExpectSurpriseRemoval. Others---ExpectOrderlyRemoval
Override Removal Policy in a Device INF File
[DDInstall.NT] <-- Replace DDInstall with the name of the install section for the device ; Contains CopyFiles and other directives
• Policy = 2 - ExpectOrderlyRemoval. The user will rarely remove the device, or will initiate removal only through software or hardware.
• Policy = 3 - ExpectSurpriseRemoval. The user will regularly remove the device with no warning to the operating system.
Override Removal Policy in a Device INF File (
SetupDiSetDeviceRegistryProperty (SPDRP_REMOVAL_POLICY is reserved for use by the operating system and cannot be used in the Property parameter)
(Windows XP and later) The function retrieves the device's current removal policy as a DWORD that contains one of the CM_REMOVAL_POLICY_Xxx values that are defined in Cfgmgr32.h.
(Windows XP and later) The function retrieves the device's hardware-specified default removal policy as a DWORD that contains one of the CM_REMOVAL_POLICY_Xxx values that are defined in Cfgmgr32.h.
(Windows XP and later) The function retrieves the device's override removal policy (if it exists) from the registry, as a DWORD that contains one of the CM_REMOVAL_POLICY_Xxx values that are defined in Cfgmgr32.h.