Deployment

The topics in this section provide information regarding the deployment of applications built with CBFS Disk. The information in these topics should be reviewed carefully when designing a deployment strategy, since CBFS Disk's kernel mode drivers and other supplementary DLLs must be distributed along with the application in order for it to function correctly.

Topics

• Driver Installation
• User Mode API

Driver Installation

At a high level, CBFS Disk consists of a kernel mode driver, a helper DLL, and a user mode library; all of which work together in tandem to provide the product's functionality. Therefore, it is necessary to install the CBFS Disk kernel mode driver and helper DLL when deploying an application built with the CBFS Disk user mode library.

The functionality needed to install the above-mentioned modules is included in the user mode library itself, as well as in a separate installer DLL. The drivers directory, located within the product's Python package (see notes below), contains the following files:

Windows: Note: When the user-mode library is installed or updated on end-user systems, it is required to ensure that the kernel-mode drivers already present in the system are updated to match the version of the installed user-mode library.

Python Package Notes

In the Python edition, the drivers directory described above is included as part of the product's Python package, <install_dir>\cbfsdisk-24.0.xxxx.tar.gz. After installing the package with pip (see the User Mode API topic), the drivers directory can be found within the product's package directory, which can be located by running pip show cbfsdisk.

Installation and Uninstallation via User Mode Library Methods

The class includes the following methods to install and uninstall the required files; please refer to their documentation for more information:

• install
• uninstall
• get_driver_status
• get_module_version
• register_icon
• unregister_icon

Important: uninstall must only be used when completely removing the driver. When updating the driver, this method must not be used as it may cause the OS to incorrectly remove the driver on reboot. Please refer to the "Updating the Driver" section, below, for more information.

Installation and Uninstallation via Installer DLL Functions

The installer DLL is a lightweight, stand-alone library that contains only the functionality required for installing and uninstalling the required files. It is available in both 32-bit and 64-bit versions (each of which is capable of installing both 32-bit and 64-bit drivers and helper DLLs); and may be used as desired in installation scripts, setup applications, or any other executable capable of loading dynamically-linked libraries (DLLs).

The functions exposed by the installer DLL mirror the class methods listed above. Each function is available in two forms: those with an *A suffix, which can be used with ANSI/UTF8 strings; and those with a *W suffix, which can be used with Unicode (UTF16) strings.

Updating the Driver

To update the driver, call the install method. The new version of the driver will replace the older version. Please do not call the uninstall method when updating the driver.

Uninstalling the Driver

To uninstall the driver completely, call the uninstall method. If the driver cannot be immediately uninstalled, it will be marked for removal and uninstalled on the next reboot.

Use caution when calling uninstall ; if it gets called and the driver cannot be uninstalled immediately, and then install is subsequently called to install a new version, then upon reboot, the OS will end up uninstalling the newly-installed driver.

Important: The driver should only be uninstalled when the intent is to completely remove it from the system. Do not uninstall the driver to update it.

Reboot Requirements

Depending on the current state of the system, as well as the options chosen when installing or uninstalling the driver, the OS may need to reboot to complete the operation.

For example, the helper DLL must be loaded by Windows File Explorer when it starts, and a reboot or restart of Explorer is required for this to occur. When installing or uninstalling the Plug-and-Play (PnP) drivers, a reboot is almost always requested by Windows.

Always check the return value of the install and uninstall methods/functions; it will indicate whether a reboot is required (and if so, which module(s) required it).

Additional Notes

The OS treats major versions of the driver as separate products; they can operate in parallel and do not share any resources. Old major versions may optionally be removed from the system when calling install by passing the appropriate value for its Flags parameter.

For each major version of the product, only one copy of the driver can be installed at any time. When the driver is being installed, its version is checked, and one of the following three things occurs:

• If no driver with the same major version is currently installed, then the install procedure installs the driver as a new product.
• If a driver with the same major version and an older minor version is currently installed, then the install procedure updates the existing driver with the new one.
• If a driver with the same major version and a newer minor version is currently installed, then the install procedure leaves the existing driver unchanged.

When deploying files to a target system, the CAB file must remain present on the system. This file is required for uninstallation of the driver at a later time.

The product's installation code maintains a ProductGUID-based record of driver installations in the Windows Registry, creating a separate registry entry for each different ProductGUID. When the driver is "uninstalled", the corresponding registry entry is removed. The driver is only removed from the system if there are no entries left in the registry that reference the driver.

Windows 7 and Windows 2008 Server R2

Kernel-mode drivers are signed using the SHA2 algorithm. The original releases of Windows 7 and Windows 2008 Server R2 didn't support SHA2. To be able to load the newest versions of the drivers, the system needs to have certain updates installed. The updates are KB976932 (Service Pack 1 of the mentioned systems) and KB4474419 (Security Update).

Required Permissions

By default, Windows only allows installation and uninstallation of the CBFS Disk system files (kernel mode drivers and helper DLLs) to be performed from a user account which is a member of the Administrators group.

On systems where UAC is enabled, the process responsible for installing or uninstalling the system files must run with elevated permissions. Detection of current privileges and elevation of permissions is not within the scope of the class itself.

Some examples of obtaining the required permissions for driver installation and uninstallation are below.

• Starting the application which uses the class with the "Run as administrator" option.
• Modifying the Load and unload device drivers setting in the Local Security Policy under the User Rights Assignment section.
• Including a manifest alongside the application indicating the requirement for elevated permissions. For instance, if a file MyApp.exe.manifest with the content below exists next to the application MyApp.exe, it will prompt for elevated permissions when started (if required).

  <?xml version="1.0" encoding="UTF-8" standalone="yes"?> <assembly xmlns="urn:schemas-microsoft-com:asm.v1" manifestVersion="1.0"> <assemblyIdentity version="1.0.0.0" processorArchitecture="X86" name="ExeName" type="win32"/> <description>elevate execution level</description> <trustInfo xmlns="urn:schemas-microsoft-com:asm.v2"> <security> <requestedPrivileges> <requestedExecutionLevel level="requireAdministrator" uiAccess="false"/> </requestedPrivileges> </security> </trustInfo> </assembly>

User Mode API

Windows Only: The user-mode library must be deployed to end-user systems along with the kernel-mode drivers; the version of the kernel-mode drivers on the end-user systems must be equal to or newer than the version of the user-mode library. Thus, when the user-mode library is installed or updated on end-user systems, it is required to ensure that the kernel-mode drivers already present in the system are updated to match the version of the installed user-mode library.

The user-mode library comes in two pieces, both of which must be deployed with the application:

• A Python module named cbfsdisk.py.
• A native dynamic library (unmanaged), named as follows:
  • Windows: pycbfsdisk24.dll (available for x64 and x86 processor architectures)
  • Linux: libpycbfsdisk.so.24.0 (available for x64 and x86 processor architectures)
  • macOS: libpycbfsdisk24.0.dylib (available for x64 and ARM64 processor architectures)

Both the module and the native library are included in the product's Python package, <install_dir>\cbfsdisk-24.0.xxxx.tar.gz, which should be installed using pip: cd C:\path\to\install_dir python -m pip install cbfsdisk-24.0.xxxx.tar.gz

Once the product's Python package has been installed, the module can be imported and used: from cbfsdisk import *. Nothing else is required to deploy the application.

As an alternative to installing the module using pip, you can utilize the built-in setuptools module to package the module for deployment or install it to the machine. python setup.py build --build-lib=<app_dir> The above setup command packages the module and native library for deployment. A folder is created in the app_dir directory with the module and the native library packaged inside.

Windows Only: Remember to deploy the drivers too, as they are an integral part of CBFS Disk.

General Information

The topics in this section provide general information about various aspects of the product's functionality.

Topics

• Thread Safety of the API
• Custom Drive Icons
• Error Handling
• Event Handling section
• Helper DLL
• Mounting Points
• Troubleshooting

Thread Safety of the API

The properties and methods provided by CBFS Disk's APIs fall into one of the following categories when it comes to thread safety:

• Properties and methods that are intended to be accessed from event handlers (i.e., those documented as such) are thread-safe, since event handlers always execute in the context of worker threads.
• Methods related to installation, uninstallation, and status retrieval are not thread-safe, since they are expected to be used during the application installation process. (Methods in this category are those which are documented as being "available in both the class API and the Installer DLL".)
• Any helper methods documented in the class's API (i.e., those used to convert error codes, or provide similar supplementary functionality) don't use any explicit thread synchronization, but also don't access any other class properties or methods, and thus are inherently thread-safe.
• All other properties and methods are not thread-safe, so applications must employ proper thread synchronization techniques when using them on multiple threads (including, but not limited to, during event handlers).

Custom Drive Icons

Virtual drives created with the CBDisk class can have a custom icon associated with them to better distinguish them in Windows File Explorer. There are a few different ways to accomplish this:

Using Additional Files

If placing additional files into the virtual drive itself is an acceptable condition, Windows provides a couple of file-based mechanisms for specifying a custom icon.

To specify a custom icon for the virtual drive itself, an autorun.inf file can be created based on the information in Microsoft's Autorun.inf article.

Additionally, custom icons can be specified for subdirectories of the virtual drive using desktop.ini files, which can be created based on the information in Microsoft's Desktop.ini article. Note that desktop.ini files cannot be used to specify a custom icon for the root directory of the virtual drive (i.e., they cannot be used to change the icon of the virtual drive itself).

Using Registry Keys

If the virtual drive is assigned a persistent drive letter, using registry keys to assign a custom icon may be a good option. To specify a custom icon using the registry, create a subkey like {DriveLetter}\DefaultIcon (e.g., K\DefaultIcon) under one of the following keys:

• HKEY_CURRENT_USER\SOFTWARE\Classes\Applications\Explorer.exe\Drives, if the custom icon should only be used for the current user.
• HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Windows\CurrentVersion\Explorer\DriveIcons, if the custom icon should be used for all users. (Note that manipulating anything under the HKEY_LOCAL_MACHINE registry hive requires administrative rights.)

Regardless of which key it is created under, the {DriveLetter}\DefaultIcon subkey's (Default) (i.e., "unnamed") value should then be set to the absolute path of the icon file.

Please note that custom icons specified in this manner are only effective so long as the drive letter assigned to the virtual drive remains unchanged over time; if its drive letter changes, the registry keys used to specify the custom icon will need to be updated accordingly.

Using the Class and its Shell Helper DLL

As long as the Helper DLL has been installed to the system using the install method, custom icons can be assigned to a virtual drive directly using the class. This method of specifying custom icons is especially valuable when project constraints preclude placing additional files into the drive or modifying the registry.

Custom icons assigned in this manner function a bit differently than those assigned using the two methods described above, as they are implemented using Windows' icon overlay mechanism. Consequently, the custom icons are restricted to 25% of the original icon's area (except for 16x16 icons); the tables below describe the required sizes and color levels of the assets in the icon file.

Overlay icon sizes map as follows:

Icon assets must have the following color levels:

Because it's possible to specify multiple different overlay icons (e.g., to represent different drive states), icons are assigned through the class using a two-step process:

1. Register the desired icon(s) using the register_icon method. (Note that administrative rights are required to execute this method successfully.)
2. Switch between the registered icon(s) using the set_icon and reset_icon methods.

Icons are copied to a temporary location when registered; and removed from said location when unregistered using the unregister_icon method.

It is important to keep in mind that Windows limits the number of registered overlay icons to 15 (this is a global limit for the entire system, and it cannot be changed). Since other applications on the system (e.g., OneDrive, Dropbox, etc.) may have registered multiple overlay icons, it's not uncommon to get into a situation where various applications are competing to have their overlay icons registered.

Overlay icons are registered by placing values in the following keys in the Registry:

• HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Windows\CurrentVersion\Explorer\ShellIconOverlayIdentifiers
• HKEY_LOCAL_MACHINE\SOFTWARE\Wow6432Node\Microsoft\Windows\CurrentVersion\explorer\ShellIconOverlayIdentifiers (64-bit Windows only)

If necessary, it's up to the application (or better yet, the user) to decide whether or not to remove other entries; however, doing so too aggressively will likely have a negative impact on the user's experience with other applications.

Error Handling

Error Codes

The CBFS Disk communicates errors using the Win32 error codes defined in WinError.h, which is part of the Windows Platform SDK. The CBFS Disk system drivers, however, use NT native error codes, which do not have one-to-one mappings with Win32 error codes. The class includes logic for converting between the two as necessary, and that logic can be updated if any codes are not covered.

Additionally, CBFS Disk uses use certain error codes in a special manner. For more information about such error codes, please refer to the Error Codes page.

Reporting Errors to the Class from Event Handlers

If an event has a ResultCode parameter, an event handler can use it to return the result code of the operation to the class. The ResultCode parameter is set to 0 by default, which indicates the operation was successful.

If an unhandled exception occurs in the event handler, it will be caught by the class, which will fire the OnError event.

In some events, the OS does not expect the error code to be returned and either the class or the OS ignores the returned error code. Please refer to the description of a particular event for more information.

How to Handle Errors Reported by the Class

If an error occurs, the class will throw an exception. The code property of the exception object will contain an error code, and the message property will contain an error message (if available).

Extended Logging in Windows

Some class methods in CBFS Disk are capable of writing extended information about reported errors to the Windows event logs, which can be viewed using the system's eventvwr.exe tool. The user mode part of the class writes to the "Windows Logs \ Application" folder, while the kernel mode part writes to the "Windows Logs \ System" folder.

The information written in the extended logs is meaningful to the Callback Technologies development team, but not to end-users, so extended logging is disabled by default. If issues occur during the installation of the CBFS Disk system drivers, or while using the class, please do the following:

1. Enable extended logging (see below).
2. Replicate the issue.
3. Using Event Viewer (eventvwr.exe), export the event log entries from the locations mentioned above in native format (please restrict the scope of the export to just those entries related to CBFS Disk).
4. Submit an issue report that includes the exported file.

There are two ways to toggle extended logging for a class:

1. By toggling the class's LoggingEnabled configuration setting.
2. By adding a DWORD-typed value named Enabled to the HKEY_LOCAL_MACHINE\SOFTWARE\Callback Technologies\{ClassName}\EventLog registry key and setting it to 0 (disabled) or 1 (enabled).
   • Replace the {ClassName} part of the registry key path with the name of the applicable class.
   • If this registry key, one of its parents, or the actual value does not exist, please create it manually.

   Note: If your code runs in emulated mode (x86 mode on x64 or ARM64 architecture), you need to add the value to the HKEY_LOCAL_MACHINE\SOFTWARE\WOW6432Node\Callback Technologies\{ClassName}\EventLog registry key in addition to the "main" registry key.

The system must be rebooted anytime extended logging is enabled or disabled to make the changes take effect.

Event Handling

The topics in this section provide information about event handling.

Topics

• Buffer Parameters
• Recursive Calls
• Timeouts

Buffer Parameters

Some events include one or more parameters intended for use as a binary data buffer. Depending on the event, these parameters may contain data when the event is fired, or it may be expected that the application populates them with the desired amount of data during the event handler. Some events combine both paradigms and then expect the application to modify the data already present when the event is fired.

The documentation for such events will describe which of these cases applies to each buffer parameter. In all cases, buffer parameters point to a preallocated block of unmanaged memory, the size of which is specified by the parameter immediately following the buffer parameter. In cases in which data are to be written, be sure to write it directly to the pointed-to memory, do not change the value of the buffer parameter itself. Buffer parameters are always of the ctypes.c_void_p type; use the ctypes.memmove() method to read and write data from and to the unmanaged memory region. To obtain a pointer to a Python buffer suitable for use with ctypes.memmove(), call ctypes.c_void_p.from_buffer() and pass it a byte array or some other type that implements Python's buffer interface.

Recursive Calls

To ensure stable operation, it is critical to avoid accessing drives and filesystems recursively. Essentially, this means that event handlers must not perform any operations involving the drive or filesystem that the event fired for (i.e., don't read from/write to files on it, don't unmount the media, etc.).

Timeouts

Because the class's events are typically tied directly to requests from the OS itself, it is critical that event handlers complete requests quickly to prevent the system from being blocked. To help prevent such blocking, the CBFS Disk system driver can enforce request timeouts on a per-virtual-drive basis.

A virtual drive's request timeout interval is specified by passing the desired number of milliseconds to the Timeout parameter when calling the mount_media method. The value passed to the Timeout parameter must either be a positive value greater than or equal to 3000, or 0, indicating that timeouts should not be enforced, in which case events may take as long as necessary to execute.

When timeout enforcement is in effect, and an event executes long enough for its timeout to expire, the driver cancels the underlying request by reporting an error to the OS. The tardy event still runs to completion, but any results it returns once finished are ignored because the underlying request has already been handled.

Applications should always strive to ensure that all event handlers complete quickly, even if request timeouts are disabled. Do not perform time-consuming work, especially network operations, within event handlers; offload such work to background threads. For example, a viable strategy for writing to a remote file would be to pass the data to be written to a background thread, and then to immediately finish the event handler. Similarly, to read from a remote file, an application could pre-cache some of its data with the help of a worker thread, and then return the cached data when requested.

Helper DLL

The Helper DLL is integrated into Windows File Explorer and offers functionality designed to provide users with a consistent and pleasant experience. It is recommended that the Helper DLL be installed alongside the system driver, which can be accomplished by including the MODULE_HELPER_DLL flag when calling the install method.

The Helper DLL is distributed in the same .cab file as the system driver; its name is CBDiskShellHelper24.dll, and it is shipped in both 32-bit and 64-bit variants. Its functionality is described below.

Mounting Point Change Broadcasts

Anytime a mounting point is added or removed, the system driver will send a notification to the Helper DLL, which then broadcasts a system message instructing Windows File Explorer to refresh the list of drives. Without this functionality, Windows File Explorer will not refresh the list of drives if a mounting point is added or removed from a Windows service or another user session.

Network Mounting Point

When a network mounting point is used, the Helper DLL provides the functionality that allows Windows File Explorer to correctly display the current status of, and interact with, the virtual drive. Without this functionality, the virtual drive will display as "Disconnected", which may result in unexpected behavior.

Custom Icons

When custom icons are used for a virtual drive, the Helper DLL ensures that they are properly displayed in Windows File Explorer.

Mounting Points

A mounting point is a name that can be used to access a volume. When the filesystem driver mounts a volume, it must make that volume accessible by creating one or more mounting points for it.

Windows:

Mounting points can be global (visible in all user sessions) or local (visible only to a specific user session). The add_mounting_point method creates global mounting points by default; applications must include the STGMP_LOCAL flag in the Flags parameter value to create local mounting points. (Note: The STGMP_MOUNT_MANAGER flag is not compatible with the STGMP_LOCAL flag.)

When creating a local mounting point, applications can specify a specific user session for it to be visible in by passing that session's Authentication ID for the AuthenticationId parameter (retrieval of Authentication IDs is discussed in a later section). If no Authentication ID is provided (i.e., 0 is passed), the local mounting point is created in the current user session; and if the application does this while running with elevated rights, then the local mounting point will only be visible in the elevated session, and consequently won't be available to applications in other sessions (such as, e.g., Windows File Explorer).

When mounting points are added or removed, a system message (WM_DEVICECHANGE) is broadcast. It instructs Windows File Explorer to refresh the list of drives available. However, these messages cannot cross user session boundaries; so if, for example, the application is running as a service, Windows File Explorer may not receive the broadcast and thus fail to refresh the list of drives. To address this issue, CBFS Disk includes a Helper DLL which, among other things, helps ensure that Windows File Explorer always refreshes the list of drives regardless of which user session the application is running in; please refer to that topic for more information.

Types of Mounting Points

There are a handful of different mounting point types, each of which exposes volumes in a slightly different manner:

• Drive letter mounting points
• Folder mounting points
• Network mounting points
• UNC path mounting points

Each type of mounting point is discussed in more detail below.

Drive Letter Mounting Points

Drive letter mounting points are one of the more commonly-used mounting point types thanks to users' familiarity with them. To create a drive letter mounting point, pass a string composed of a single character in the A-Z range followed by a colon (e.g., Z:) for the add_mounting_point method's MountingPoint parameter.

If the value passed for the add_mounting_point method's Flags parameter includes the STGMP_AUTOCREATE_DRIVE_LETTER flag, the class will assign a drive letter automatically. In this case, the value passed for the MountingPoint parameter must not include a drive letter.

Folder Mounting Points

A folder mounting point makes a volume accessible through a folder located on another (pre-existing) NTFS volume. Folder mounting points are always visible to all users in the system, and their creation requires administrative privileges.

To create a folder mounting point using the add_mounting_point method, include the STGMP_MOUNT_MANAGER flag in the Flags parameter , and pass the target folder's absolute path for the MountingPoint parameter (e.g., C:\MountedDrives\MyMountingPoint). The target folder must already exist, must reside on an NTFS volume, and must be empty; otherwise, the call will fail.

Authentication IDs

An Authentication ID is a locally unique identifier (LUID) assigned to a logon session (or, "user session"), retrievable through the access token that represents said session. Applications can obtain the Authentication ID of a session from an access token or by enumerating logon sessions.

To obtain an Authentication ID from an access token, call the Windows API's GetTokenInformation function and pass either TokenGroupsAndPrivileges or TokenStatistics for the TokenInformation parameter. The resulting value will be a reference to a structure (TOKEN_GROUPS_AND_PRIVILEGES or TOKEN_STATISTICS, respectively) containing the needed Authentication ID.

To enumerate logon sessions, use the Windows API's LsaEnumerateLogonSessions function, which returns a list of existing logon session IDs (that is, Authentication IDs). To obtain additional information about a particular logon session (e.g., in order to determine if it's the desired one), use the Windows API's LsaGetLogonSessionData function. Network Mounting Points

Network mounting points are similar to other mounting point types, except that the system treats them as "remote devices". This distinction is useful since:

• Windows File Explorer makes fewer requests for files located on remote devices.
• Some applications are more tolerant of timeouts and delays when working with remote devices.

Therefore, when an application is designed to work with some slow or remote storage medium, it's recommended that it use a network mounting point. When using network mounting points, it's important that the Helper DLL be used so that Windows File Explorer displays the correct drive status.

To create a network mounting point using the add_mounting_point method, include the STGMP_NETWORK flag in the Flags parameter, and pass a string of the form <Local Name>;<Server Name>;<Share Name> for the MountingPoint parameter.

• <Local Name> is the name to use for the mounting point on the local system; it can be a drive letter or a name for use in a UNC path. Alternatively, it can be left empty, in which case the volume will only be accessible via the network path (see below) or the drive letter will be assigned automatically if the STGMP_AUTOCREATE_DRIVE_LETTER flag is used.
  • Note: This "local name" is not related to the concept of "local and global mounting points" discussed in the overview.
• <Server Name> and <Share Name> are used to create a network path of the form \\<Server Name>\<Share Name>. This network path is not shared by default (see notes following examples below).

The set of characters allowed in server names, is defined in this document. The set of characters allowed in share names, is defined in this document.

With the above information in mind, here are some examples of valid MountingPoint parameter values when creating network mounting points:

• Y:;MyServer;VirtualShare: Creates a network mounting point accessible both via the drive letter Y: and via the network path \\MyServer\VirtualShare.
• MyMountingPoint;MyServer;VirtualShare: Creates a network mounting point accessible both via the UNC path \\.\MyMountingPoint and via the network path \\MyServer\VirtualShare
• ;MyServer;VirtualShare: Creates a network mounting point accessible only via the network path \\MyServer\VirtualShare.

As stated above, the network paths created for network mounting points are not shared (i.e., visible to other computers on the network) by default. To have the class create an actual network share when add_mounting_point is called, applications must include either the STGMP_NETWORK_READ_ACCESS or the STGMP_NETWORK_WRITE_ACCESS flag in the Flags parameter value, and use empty string for the <Server Name> segment of the MountingPoint parameter value (the local computer's name is used). Note that when the mounting point is shared in this way, a local resource is created and then shared. The name of the resource is derived from the Share Name defined above. However, the set of allowed characters for such name is not strictly defined. Additionally, sharing is done using a call to NetShareAdd Windows API function, which can be called by Administrators, System Operators, and Power Users.

UNC Path Mounting Points

UNC path mounting points make a volume available via a specific name, and unlike other mounting points types, they are not displayed anywhere in Windows File Explorer; the UNC path must already be known.

UNC path mounting points consist of the \\.\ prefix, followed by a name (e.g., \\.\CBDrive1). The mounting-point-related class methods expect just the name (i.e., the UNC path with the \\.\ prefix omitted). So to add a new UNC path mounting point like, e.g., \\.\CBDrive1, call the add_mounting_point method and pass CBDrive1 for the MountingPoint parameter.

Linux and macOS:

A virtual drive / filesystem is mounted to a directory, which must exist at the time of mounting and be empty; otherwise, the call will fail.

Troubleshooting

Note: The below information applies to the operations of the class on Windows .

CBFS Disk is a complex product that operates in both user mode and kernel mode simultaneously; so when a serious issue occurs, it's critical that we are able to obtain sufficient information about the circumstances of the failure.

In order to help us assist you in a more expedient manner, please collect the information described in the instructions below when reporting a serious issue (i.e., one that causes the system to crash or hang). Our development team cannot effectively diagnose such issues without this information.

Also, please note that these sorts of issues commonly involve environmental differences and other factors that are either unforeseen or otherwise out of our control. It is also not unheard-of for a crash to appear attributable to one thing while in fact being caused by something completely different. Rest assured that we are committed to assisting you as best we can, and we thank you ahead-of-time for your patience and understanding throughout the support process.

System Crashes (BSODs)

If you encounter a consistently-reproducible system crash (BSOD) that you suspect may be due to CBFS Disk, please obtain a crash dump and include it when reporting the issue to us. Our development team is unable to diagnose system crashes without the information these dumps contain.

Ensure that your system is set up to generate crash dumps, and to not restart automatically after a crash, by following the steps found in Microsoft's Enabling a Kernel-Mode Dump File article. The options available in the memory dump dropdown vary depending on your version of Windows; please choose the first one from the following list that is present in yours:

• Complete
• Full
• Automatic
• Kernel

Once your system is set up to generate crash dumps, perform the same action that caused the BSOD originally to trigger the crash again. When it occurs, be sure to copy the information on the BSOD screen exactly so that it can be included in your submission (a picture of the screen in which all of the information is legible is also acceptable). Here are some examples of the specific information we're looking for:

Recent versions of Windows:

What failed: cb***24.sys Stop Code: FILE_SYSTEM

Older versions of Windows:

STOP: 0x00000022 (0x00240076, 0xF7A07AA8, 0xF7A077A8, 0xF7800C82) cb***24.sys - Address F7800C82 base at F77CD000, DateStamp 447d6975

After you've copied this information, reboot and check that the memory dump file was created at %SYSTEMROOT%\MEMORY.DMP (typically this is C:\Windows\MEMORY.DMP; if you changed the dump file location in the crash dump settings, check the location you specified instead). It will be a very large file that is too big to attach to an email, so please upload it to a file sharing site of your choice and generate a sharing link that our development team can use to download it.

Finally, submit a support issue to us that includes the link to your dump file, all of the information from the BSOD screen (if you took a picture, attach it or provide another sharing link), a description of how the BSOD was triggered, and any other information that you feel is relevant.

System Hangs

If you encounter a consistently-reproducible system hang that you suspect may be due to CBFS Disk, you'll need to collect the same information as described above. But in order to obtain a crash dump, you'll first need to configure your system so that you can trigger a crash from the keyboard once it hangs. To make this possible, follow these steps (adapted from Microsoft's Forcing a System Crash from the Keyboard article):

1. First, using the instructions provided in the section above, configure your system to generate crash dumps, and to not restart automatically after a crash.
2. Next, you must enable keyboard-initiated crashes in the registry by creating a new value named CrashOnCtrlScroll, and setting it equal to a REG_DWORD value of 0x01, in all of the following registry keys:
   • HKEY_LOCAL_MACHINE\System\CurrentControlSet\Services\i8042prt\Parameters
   • HKEY_LOCAL_MACHINE\System\CurrentControlSet\Services\kbdhid\Parameters
   • HKEY_LOCAL_MACHINE\System\CurrentControlSet\Services\hyperkbd\Parameters
3. Finally, you must restart the system in order for these settings to take effect.

After these steps are complete, you'll be able to trigger a keyboard-initiated crash by using the following hotkey sequence: hold down the Right CTRL key, and press the SCROLL LOCK key twice.

At this point, you can perform the same action that caused the system to hang originally to trigger the hang again. Once the system hangs, use the hotkey sequence to force it to crash, and then follow the rest of the instructions from the section above to collect and submit the necessary information.

Method Never Returns

If your application makes a call to some CBFS Disk method and that method never returns, there's a high chance that the driver deadlock has occurred. This can be caused by various factors; to determine the reason and possible solutions, we need a memory dump, as described above. If your system remains functional, you may also use easier ways to initiate a crash:

1. Use the NotMyFault tool by SysInternals to initiate a system crash. This is the preferred way because it generates Complete memory dumps. This tool has a self-explanatory GUI.
2. Use the LiveKD tool by SysInternals to create a live memory dump without crashing a system. The disadvantage of this method is that it creates Kernel dumps that are missing user-mode information. To use LiveKD on 32-bit systems, use this command: "livekd.exe -ml -o memory.dmp". On 64-bit systems, the command line would be "livekd64.exe -ml -k .\kd64.exe -o memory.dmp".

Application Crashes

Sometimes, an application crashes while the OS continues to operate, and the name of one of the modules of CBFS Disk is present in the crash information. A crashing application can be the one that uses CBFS Disk or some third-party process. If the crash occurs repeatedly, it is possible to make use of a User-Mode Crash Dump to locate or narrow down the source of the crash. Generation of crash dumps is disabled by default. Before you reproduce the crash, you need to Enable Collecting User-Mode Crash Dumps.

After you enable the crash dump, you don't need to reboot, you can proceed to reproduction of the crash immediately. After the crash re-occurs, you can pick the dump file from its location. The default locations of user-mode dump files are:

• For regular applications: %LOCALAPPDATA%\CrashDumps
• For System services: %WINDIR%\System32\Config\SystemProfile
• For Network and Local services: %WINDIR%\ServiceProfiles

If you changed the dump file location in the crash dump settings in the Registry, check the location you specified instead.

A crash dump can be a large file (depending on the settings) that is too big to attach to an email, so please upload it to a file sharing site of your choice and generate a sharing link that our development team can use to download it.

Finally, submit a support issue to us that includes the link to your dump file, a description of how the BSOD or a manual crash was triggered, and any other information that you feel is relevant.