[rtems-docs commit] c-user: Move "Filesystem Configuration"
Sebastian Huber
sebh at rtems.org
Thu Mar 12 09:32:36 UTC 2020
Module: rtems-docs
Branch: master
Commit: c0a70dba6154f605226b2e1f763875f8d00f9a7b
Changeset: http://git.rtems.org/rtems-docs/commit/?id=c0a70dba6154f605226b2e1f763875f8d00f9a7b
Author: Sebastian Huber <sebastian.huber at embedded-brains.de>
Date: Mon Mar 9 08:51:47 2020 +0100
c-user: Move "Filesystem Configuration"
Update #3836.
---
c-user/config/filesystem.rst | 547 +++++++++++++++++++++++++++++++++++++++++++
c-user/config/index.rst | 545 +-----------------------------------------
2 files changed, 548 insertions(+), 544 deletions(-)
diff --git a/c-user/config/filesystem.rst b/c-user/config/filesystem.rst
new file mode 100644
index 0000000..063a8c3
--- /dev/null
+++ b/c-user/config/filesystem.rst
@@ -0,0 +1,547 @@
+.. SPDX-License-Identifier: CC-BY-SA-4.0
+
+.. Copyright (C) 1988, 2008 On-Line Applications Research Corporation (OAR)
+
+Filesystem Configuration
+========================
+
+By default, the In-Memory Filesystem (IMFS) is used as the base filesystem (also
+known as root filesystem). In order to save some memory for your application,
+you can disable the filesystem support with the
+:ref:`CONFIGURE_APPLICATION_DISABLE_FILESYSTEM` configuration option.
+Alternatively, you can strip down the features of the base filesystem with the
+:ref:`CONFIGURE_USE_MINIIMFS_AS_BASE_FILESYSTEM` and
+:ref:`CONFIGURE_USE_DEVFS_AS_BASE_FILESYSTEM` configuration options. These
+three configuration options are mutually exclusive. They are intended for an
+advanced application configuration.
+
+Features of the IMFS can be disabled and enabled with the following
+configuration options:
+
+* :ref:`CONFIGURE_IMFS_DISABLE_CHMOD`
+
+* :ref:`CONFIGURE_IMFS_DISABLE_CHOWN`
+
+* :ref:`CONFIGURE_IMFS_DISABLE_LINK`
+
+* :ref:`CONFIGURE_IMFS_DISABLE_MKNOD`
+
+* :ref:`CONFIGURE_IMFS_DISABLE_MKNOD_FILE`
+
+* :ref:`CONFIGURE_IMFS_DISABLE_MOUNT`
+
+* :ref:`CONFIGURE_IMFS_DISABLE_READDIR`
+
+* :ref:`CONFIGURE_IMFS_DISABLE_READLINK`
+
+* :ref:`CONFIGURE_IMFS_DISABLE_RENAME`
+
+* :ref:`CONFIGURE_IMFS_DISABLE_RMNOD`
+
+* :ref:`CONFIGURE_IMFS_DISABLE_SYMLINK`
+
+* :ref:`CONFIGURE_IMFS_DISABLE_UNMOUNT`
+
+* :ref:`CONFIGURE_IMFS_DISABLE_UTIME`
+
+* :ref:`CONFIGURE_IMFS_ENABLE_MKFIFO`
+
+.. index:: CONFIGURE_APPLICATION_DISABLE_FILESYSTEM
+
+.. _CONFIGURE_APPLICATION_DISABLE_FILESYSTEM:
+
+CONFIGURE_APPLICATION_DISABLE_FILESYSTEM
+----------------------------------------
+
+CONSTANT:
+ ``CONFIGURE_APPLICATION_DISABLE_FILESYSTEM``
+
+DATA TYPE:
+ Boolean feature macro.
+
+RANGE:
+ Defined or undefined.
+
+DEFAULT VALUE:
+ This is not defined by default. If no other root file system configuration
+ parameters are specified, the IMFS will be used as the root file system.
+
+DESCRIPTION:
+ This configuration parameter is defined if the application dose not intend
+ to use any kind of filesystem support. This include the device
+ infrastructure necessary to support ``printf()``.
+
+NOTES:
+ None.
+
+.. index:: CONFIGURE_IMFS_ENABLE_MKFIFO
+
+.. _CONFIGURE_IMFS_ENABLE_MKFIFO:
+
+CONFIGURE_IMFS_ENABLE_MKFIFO
+----------------------------
+
+CONSTANT:
+ ``CONFIGURE_IMFS_ENABLE_MKFIFO``
+
+DATA TYPE:
+ Boolean feature macro.
+
+RANGE:
+ Defined or undefined.
+
+DEFAULT VALUE:
+ This is not defined by default.
+
+DESCRIPTION:
+ In case this configuration option is defined, then the support to make FIFOs
+ is enabled in the root IMFS.
+
+.. index:: CONFIGURE_IMFS_DISABLE_CHMOD
+
+.. _CONFIGURE_IMFS_DISABLE_CHMOD:
+
+CONFIGURE_IMFS_DISABLE_CHMOD
+----------------------------
+
+CONSTANT:
+ ``CONFIGURE_IMFS_DISABLE_CHMOD``
+
+DATA TYPE:
+ Boolean feature macro.
+
+RANGE:
+ Defined or undefined.
+
+DEFAULT VALUE:
+ This is not defined by default.
+
+DESCRIPTION:
+ In case this configuration option is defined, then the support to change
+ the mode is disabled in the root IMFS.
+
+.. index:: CONFIGURE_IMFS_DISABLE_CHOWN
+
+.. _CONFIGURE_IMFS_DISABLE_CHOWN:
+
+CONFIGURE_IMFS_DISABLE_CHOWN
+----------------------------
+
+CONSTANT:
+ ``CONFIGURE_IMFS_DISABLE_CHOWN``
+
+DATA TYPE:
+ Boolean feature macro.
+
+RANGE:
+ Defined or undefined.
+
+DEFAULT VALUE:
+ This is not defined by default.
+
+DESCRIPTION:
+ In case this configuration option is defined, then the support to change
+ the owner is disabled in the root IMFS.
+
+.. index:: CONFIGURE_IMFS_DISABLE_LINK
+
+.. _CONFIGURE_IMFS_DISABLE_LINK:
+
+CONFIGURE_IMFS_DISABLE_LINK
+---------------------------
+
+CONSTANT:
+ ``CONFIGURE_IMFS_DISABLE_LINK``
+
+DATA TYPE:
+ Boolean feature macro.
+
+RANGE:
+ Defined or undefined.
+
+DEFAULT VALUE:
+ This is not defined by default.
+
+DESCRIPTION:
+ In case this configuration option is defined, then the support to create
+ hard links is disabled in the root IMFS.
+
+.. index:: CONFIGURE_IMFS_DISABLE_MKNOD
+
+.. _CONFIGURE_IMFS_DISABLE_MKNOD:
+
+CONFIGURE_IMFS_DISABLE_MKNOD
+----------------------------
+
+CONSTANT:
+ ``CONFIGURE_IMFS_DISABLE_MKNOD``
+
+DATA TYPE:
+ Boolean feature macro.
+
+RANGE:
+ Defined or undefined.
+
+DEFAULT VALUE:
+ This is not defined by default.
+
+DESCRIPTION:
+ In case this configuration option is defined, then the support to make
+ directories, devices, regular files and FIFOs is disabled in the root IMFS.
+
+.. index:: CONFIGURE_IMFS_DISABLE_MKNOD_FILE
+
+.. _CONFIGURE_IMFS_DISABLE_MKNOD_FILE:
+
+CONFIGURE_IMFS_DISABLE_MKNOD_FILE
+---------------------------------
+
+CONSTANT:
+ ``CONFIGURE_IMFS_DISABLE_MKNOD_FILE``
+
+DATA TYPE:
+ Boolean feature macro.
+
+RANGE:
+ Defined or undefined.
+
+DEFAULT VALUE:
+ This is not defined by default.
+
+DESCRIPTION:
+ In case this configuration option is defined, then the support to make
+ regular files is disabled in the root IMFS.
+
+.. index:: CONFIGURE_IMFS_DISABLE_MOUNT
+
+.. _CONFIGURE_IMFS_DISABLE_MOUNT:
+
+CONFIGURE_IMFS_DISABLE_MOUNT
+----------------------------
+
+CONSTANT:
+ ``CONFIGURE_IMFS_DISABLE_MOUNT``
+
+DATA TYPE:
+ Boolean feature macro.
+
+RANGE:
+ Defined or undefined.
+
+DEFAULT VALUE:
+ This is not defined by default.
+
+DESCRIPTION:
+ In case this configuration option is defined, then the support to mount
+ other file systems is disabled in the root IMFS.
+
+.. index:: CONFIGURE_IMFS_DISABLE_READDIR
+
+.. _CONFIGURE_IMFS_DISABLE_READDIR:
+
+CONFIGURE_IMFS_DISABLE_READDIR
+------------------------------
+
+CONSTANT:
+ ``CONFIGURE_IMFS_DISABLE_READDIR``
+
+DATA TYPE:
+ Boolean feature macro.
+
+RANGE:
+ Defined or undefined.
+
+DEFAULT VALUE:
+ This is not defined by default.
+
+DESCRIPTION:
+ In case this configuration option is defined, then the support to read a
+ directory is disabled in the root IMFS. It is still possible to open nodes
+ in a directory.
+
+.. index:: CONFIGURE_IMFS_DISABLE_READLINK
+
+.. _CONFIGURE_IMFS_DISABLE_READLINK:
+
+CONFIGURE_IMFS_DISABLE_READLINK
+-------------------------------
+
+CONSTANT:
+ ``CONFIGURE_IMFS_DISABLE_READLINK``
+
+DATA TYPE:
+ Boolean feature macro.
+
+RANGE:
+ Defined or undefined.
+
+DEFAULT VALUE:
+ This is not defined by default.
+
+DESCRIPTION:
+ In case this configuration option is defined, then the support to read
+ symbolic links is disabled in the root IMFS.
+
+.. index:: CONFIGURE_IMFS_DISABLE_RENAME
+
+.. _CONFIGURE_IMFS_DISABLE_RENAME:
+
+CONFIGURE_IMFS_DISABLE_RENAME
+-----------------------------
+
+CONSTANT:
+ ``CONFIGURE_IMFS_DISABLE_RENAME``
+
+DATA TYPE:
+ Boolean feature macro.
+
+RANGE:
+ Defined or undefined.
+
+DEFAULT VALUE:
+ This is not defined by default.
+
+DESCRIPTION:
+ In case this configuration option is defined, then the support to rename
+ nodes is disabled in the root IMFS.
+
+.. index:: CONFIGURE_IMFS_DISABLE_RMNOD
+
+.. _CONFIGURE_IMFS_DISABLE_RMNOD:
+
+CONFIGURE_IMFS_DISABLE_RMNOD
+----------------------------
+
+CONSTANT:
+ ``CONFIGURE_IMFS_DISABLE_RMNOD``
+
+DATA TYPE:
+ Boolean feature macro.
+
+RANGE:
+ Defined or undefined.
+
+DEFAULT VALUE:
+ This is not defined by default.
+
+DESCRIPTION:
+ In case this configuration option is defined, then the support to remove
+ nodes is disabled in the root IMFS.
+
+.. index:: CONFIGURE_IMFS_DISABLE_SYMLINK
+
+.. _CONFIGURE_IMFS_DISABLE_SYMLINK:
+
+CONFIGURE_IMFS_DISABLE_SYMLINK
+------------------------------
+
+CONSTANT:
+ ``CONFIGURE_IMFS_DISABLE_SYMLINK``
+
+DATA TYPE:
+ Boolean feature macro.
+
+RANGE:
+ Defined or undefined.
+
+DEFAULT VALUE:
+ This is not defined by default.
+
+DESCRIPTION:
+ In case this configuration option is defined, then the support to create
+ symbolic links is disabled in the root IMFS.
+
+.. index:: CONFIGURE_IMFS_DISABLE_UNMOUNT
+
+.. _CONFIGURE_IMFS_DISABLE_UNMOUNT:
+
+CONFIGURE_IMFS_DISABLE_UNMOUNT
+------------------------------
+
+CONSTANT:
+ ``CONFIGURE_IMFS_DISABLE_UNMOUNT``
+
+DATA TYPE:
+ Boolean feature macro.
+
+RANGE:
+ Defined or undefined.
+
+DEFAULT VALUE:
+ This is not defined by default.
+
+DESCRIPTION:
+ In case this configuration option is defined, then the support to unmount
+ file systems is disabled in the root IMFS.
+
+.. index:: CONFIGURE_IMFS_DISABLE_UTIME
+
+.. _CONFIGURE_IMFS_DISABLE_UTIME:
+
+CONFIGURE_IMFS_DISABLE_UTIME
+----------------------------
+
+CONSTANT:
+ ``CONFIGURE_IMFS_DISABLE_UTIME``
+
+DATA TYPE:
+ Boolean feature macro.
+
+RANGE:
+ Defined or undefined.
+
+DEFAULT VALUE:
+ This is not defined by default.
+
+DESCRIPTION:
+ In case this configuration option is defined, then the support to change
+ times is disabled in the root IMFS.
+
+.. index:: CONFIGURE_IMFS_MEMFILE_BYTES_PER_BLOCK
+
+.. _CONFIGURE_IMFS_MEMFILE_BYTES_PER_BLOCK:
+
+CONFIGURE_IMFS_MEMFILE_BYTES_PER_BLOCK
+--------------------------------------
+
+CONSTANT:
+ ``CONFIGURE_IMFS_MEMFILE_BYTES_PER_BLOCK``
+
+DATA TYPE:
+ Boolean feature macro.
+
+RANGE:
+ Valid values for this configuration parameter are a power of two (2)
+ between 16 and 512 inclusive. In other words, valid values are 16, 32, 64,
+ 128, 256,and 512.
+
+DEFAULT VALUE:
+ The default IMFS block size is 128 bytes.
+
+DESCRIPTION:
+ This configuration parameter specifies the block size for in-memory files
+ managed by the IMFS. The configured block size has two impacts. The first
+ is the average amount of unused memory in the last block of each file. For
+ example, when the block size is 512, on average one-half of the last block
+ of each file will remain unused and the memory is wasted. In contrast, when
+ the block size is 16, the average unused memory per file is only 8
+ bytes. However, it requires more allocations for the same size file and
+ thus more overhead per block for the dynamic memory management.
+
+ Second, the block size has an impact on the maximum size file that can be
+ stored in the IMFS. With smaller block size, the maximum file size is
+ correspondingly smaller. The following shows the maximum file size possible
+ based on the configured block size:
+
+ - when the block size is 16 bytes, the maximum file size is 1,328 bytes.
+
+ - when the block size is 32 bytes, the maximum file size is 18,656 bytes.
+
+ - when the block size is 64 bytes, the maximum file size is 279,488 bytes.
+
+ - when the block size is 128 bytes, the maximum file size is 4,329,344 bytes.
+
+ - when the block size is 256 bytes, the maximum file size is 68,173,568 bytes.
+
+ - when the block size is 512 bytes, the maximum file size is 1,082,195,456
+ bytes.
+
+.. index:: CONFIGURE_MAXIMUM_DEVICES
+
+.. _CONFIGURE_MAXIMUM_DEVICES:
+
+CONFIGURE_MAXIMUM_DEVICES
+-------------------------
+
+CONSTANT:
+ ``CONFIGURE_MAXIMUM_DEVICES``
+
+DATA TYPE:
+ Unsigned integer (``uint32_t``).
+
+RANGE:
+ Positive.
+
+DEFAULT VALUE:
+ If ``BSP_MAXIMUM_DEVICES`` is defined, then the default value is
+ ``BSP_MAXIMUM_DEVICES``, otherwise the default value is 4.
+
+DESCRIPTION:
+ ``CONFIGURE_MAXIMUM_DEVICES`` is defined to the number of individual
+ devices that may be registered in the device file system (devFS).
+
+NOTES:
+ This option is specific to the device file system (devFS) and should not be
+ confused with the ``CONFIGURE_MAXIMUM_DRIVERS`` option. This parameter
+ only impacts the devFS and thus is only used by ``<rtems/confdefs.h>`` when
+ ``CONFIGURE_USE_DEVFS_AS_BASE_FILESYSTEM`` is specified.
+
+.. index:: CONFIGURE_USE_DEVFS_AS_BASE_FILESYSTEM
+
+.. _CONFIGURE_USE_DEVFS_AS_BASE_FILESYSTEM:
+
+CONFIGURE_USE_DEVFS_AS_BASE_FILESYSTEM
+--------------------------------------
+
+CONSTANT:
+ ``CONFIGURE_USE_DEVFS_AS_BASE_FILESYSTEM``
+
+DATA TYPE:
+ Boolean feature macro.
+
+RANGE:
+ Defined or undefined.
+
+DEFAULT VALUE:
+ This is not defined by default. If no other root file system configuration
+ parameters are specified, the IMFS will be used as the root file system.
+
+DESCRIPTION:
+ This configuration parameter is defined if the application wishes to use
+ the device-only filesytem as the root file system.
+
+NOTES:
+ The device-only filesystem supports only device nodes and is smaller in
+ executable code size than the full IMFS and miniIMFS.
+
+ The devFS is comparable in functionality to the pseudo-filesystem name
+ space provided before RTEMS release 4.5.0.
+
+.. index:: CONFIGURE_USE_MINIIMFS_AS_BASE_FILESYSTEM
+
+.. _CONFIGURE_USE_MINIIMFS_AS_BASE_FILESYSTEM:
+
+CONFIGURE_USE_MINIIMFS_AS_BASE_FILESYSTEM
+-----------------------------------------
+
+CONSTANT:
+ ``CONFIGURE_USE_MINIIMFS_AS_BASE_FILESYSTEM``
+
+DATA TYPE:
+ Boolean feature macro.
+
+RANGE:
+ Defined or undefined.
+
+DEFAULT VALUE:
+ This is not defined by default.
+
+DESCRIPTION:
+ In case this configuration option is defined, then the following
+ configuration options will be defined as well
+
+ - ``CONFIGURE_IMFS_DISABLE_CHMOD``,
+
+ - ``CONFIGURE_IMFS_DISABLE_CHOWN``,
+
+ - ``CONFIGURE_IMFS_DISABLE_UTIME``,
+
+ - ``CONFIGURE_IMFS_DISABLE_LINK``,
+
+ - ``CONFIGURE_IMFS_DISABLE_SYMLINK``,
+
+ - ``CONFIGURE_IMFS_DISABLE_READLINK``,
+
+ - ``CONFIGURE_IMFS_DISABLE_RENAME``, and
+
+ - ``CONFIGURE_IMFS_DISABLE_UNMOUNT``.
diff --git a/c-user/config/index.rst b/c-user/config/index.rst
index 54e2fb2..8e9f41b 100644
--- a/c-user/config/index.rst
+++ b/c-user/config/index.rst
@@ -19,550 +19,7 @@ Configuring a System
posix-init-thread
task-stack-alloc
msg-queue-buffer
-
-Filesystem Configuration
-========================
-
-By default, the In-Memory Filesystem (IMFS) is used as the base filesystem (also
-known as root filesystem). In order to save some memory for your application,
-you can disable the filesystem support with the
-:ref:`CONFIGURE_APPLICATION_DISABLE_FILESYSTEM` configuration option.
-Alternatively, you can strip down the features of the base filesystem with the
-:ref:`CONFIGURE_USE_MINIIMFS_AS_BASE_FILESYSTEM` and
-:ref:`CONFIGURE_USE_DEVFS_AS_BASE_FILESYSTEM` configuration options. These
-three configuration options are mutually exclusive. They are intended for an
-advanced application configuration.
-
-Features of the IMFS can be disabled and enabled with the following
-configuration options:
-
-* :ref:`CONFIGURE_IMFS_DISABLE_CHMOD`
-
-* :ref:`CONFIGURE_IMFS_DISABLE_CHOWN`
-
-* :ref:`CONFIGURE_IMFS_DISABLE_LINK`
-
-* :ref:`CONFIGURE_IMFS_DISABLE_MKNOD`
-
-* :ref:`CONFIGURE_IMFS_DISABLE_MKNOD_FILE`
-
-* :ref:`CONFIGURE_IMFS_DISABLE_MOUNT`
-
-* :ref:`CONFIGURE_IMFS_DISABLE_READDIR`
-
-* :ref:`CONFIGURE_IMFS_DISABLE_READLINK`
-
-* :ref:`CONFIGURE_IMFS_DISABLE_RENAME`
-
-* :ref:`CONFIGURE_IMFS_DISABLE_RMNOD`
-
-* :ref:`CONFIGURE_IMFS_DISABLE_SYMLINK`
-
-* :ref:`CONFIGURE_IMFS_DISABLE_UNMOUNT`
-
-* :ref:`CONFIGURE_IMFS_DISABLE_UTIME`
-
-* :ref:`CONFIGURE_IMFS_ENABLE_MKFIFO`
-
-.. index:: CONFIGURE_APPLICATION_DISABLE_FILESYSTEM
-
-.. _CONFIGURE_APPLICATION_DISABLE_FILESYSTEM:
-
-CONFIGURE_APPLICATION_DISABLE_FILESYSTEM
-----------------------------------------
-
-CONSTANT:
- ``CONFIGURE_APPLICATION_DISABLE_FILESYSTEM``
-
-DATA TYPE:
- Boolean feature macro.
-
-RANGE:
- Defined or undefined.
-
-DEFAULT VALUE:
- This is not defined by default. If no other root file system configuration
- parameters are specified, the IMFS will be used as the root file system.
-
-DESCRIPTION:
- This configuration parameter is defined if the application dose not intend
- to use any kind of filesystem support. This include the device
- infrastructure necessary to support ``printf()``.
-
-NOTES:
- None.
-
-.. index:: CONFIGURE_IMFS_ENABLE_MKFIFO
-
-.. _CONFIGURE_IMFS_ENABLE_MKFIFO:
-
-CONFIGURE_IMFS_ENABLE_MKFIFO
-----------------------------
-
-CONSTANT:
- ``CONFIGURE_IMFS_ENABLE_MKFIFO``
-
-DATA TYPE:
- Boolean feature macro.
-
-RANGE:
- Defined or undefined.
-
-DEFAULT VALUE:
- This is not defined by default.
-
-DESCRIPTION:
- In case this configuration option is defined, then the support to make FIFOs
- is enabled in the root IMFS.
-
-.. index:: CONFIGURE_IMFS_DISABLE_CHMOD
-
-.. _CONFIGURE_IMFS_DISABLE_CHMOD:
-
-CONFIGURE_IMFS_DISABLE_CHMOD
-----------------------------
-
-CONSTANT:
- ``CONFIGURE_IMFS_DISABLE_CHMOD``
-
-DATA TYPE:
- Boolean feature macro.
-
-RANGE:
- Defined or undefined.
-
-DEFAULT VALUE:
- This is not defined by default.
-
-DESCRIPTION:
- In case this configuration option is defined, then the support to change
- the mode is disabled in the root IMFS.
-
-.. index:: CONFIGURE_IMFS_DISABLE_CHOWN
-
-.. _CONFIGURE_IMFS_DISABLE_CHOWN:
-
-CONFIGURE_IMFS_DISABLE_CHOWN
-----------------------------
-
-CONSTANT:
- ``CONFIGURE_IMFS_DISABLE_CHOWN``
-
-DATA TYPE:
- Boolean feature macro.
-
-RANGE:
- Defined or undefined.
-
-DEFAULT VALUE:
- This is not defined by default.
-
-DESCRIPTION:
- In case this configuration option is defined, then the support to change
- the owner is disabled in the root IMFS.
-
-.. index:: CONFIGURE_IMFS_DISABLE_LINK
-
-.. _CONFIGURE_IMFS_DISABLE_LINK:
-
-CONFIGURE_IMFS_DISABLE_LINK
----------------------------
-
-CONSTANT:
- ``CONFIGURE_IMFS_DISABLE_LINK``
-
-DATA TYPE:
- Boolean feature macro.
-
-RANGE:
- Defined or undefined.
-
-DEFAULT VALUE:
- This is not defined by default.
-
-DESCRIPTION:
- In case this configuration option is defined, then the support to create
- hard links is disabled in the root IMFS.
-
-.. index:: CONFIGURE_IMFS_DISABLE_MKNOD
-
-.. _CONFIGURE_IMFS_DISABLE_MKNOD:
-
-CONFIGURE_IMFS_DISABLE_MKNOD
-----------------------------
-
-CONSTANT:
- ``CONFIGURE_IMFS_DISABLE_MKNOD``
-
-DATA TYPE:
- Boolean feature macro.
-
-RANGE:
- Defined or undefined.
-
-DEFAULT VALUE:
- This is not defined by default.
-
-DESCRIPTION:
- In case this configuration option is defined, then the support to make
- directories, devices, regular files and FIFOs is disabled in the root IMFS.
-
-.. index:: CONFIGURE_IMFS_DISABLE_MKNOD_FILE
-
-.. _CONFIGURE_IMFS_DISABLE_MKNOD_FILE:
-
-CONFIGURE_IMFS_DISABLE_MKNOD_FILE
----------------------------------
-
-CONSTANT:
- ``CONFIGURE_IMFS_DISABLE_MKNOD_FILE``
-
-DATA TYPE:
- Boolean feature macro.
-
-RANGE:
- Defined or undefined.
-
-DEFAULT VALUE:
- This is not defined by default.
-
-DESCRIPTION:
- In case this configuration option is defined, then the support to make
- regular files is disabled in the root IMFS.
-
-.. index:: CONFIGURE_IMFS_DISABLE_MOUNT
-
-.. _CONFIGURE_IMFS_DISABLE_MOUNT:
-
-CONFIGURE_IMFS_DISABLE_MOUNT
-----------------------------
-
-CONSTANT:
- ``CONFIGURE_IMFS_DISABLE_MOUNT``
-
-DATA TYPE:
- Boolean feature macro.
-
-RANGE:
- Defined or undefined.
-
-DEFAULT VALUE:
- This is not defined by default.
-
-DESCRIPTION:
- In case this configuration option is defined, then the support to mount
- other file systems is disabled in the root IMFS.
-
-.. index:: CONFIGURE_IMFS_DISABLE_READDIR
-
-.. _CONFIGURE_IMFS_DISABLE_READDIR:
-
-CONFIGURE_IMFS_DISABLE_READDIR
-------------------------------
-
-CONSTANT:
- ``CONFIGURE_IMFS_DISABLE_READDIR``
-
-DATA TYPE:
- Boolean feature macro.
-
-RANGE:
- Defined or undefined.
-
-DEFAULT VALUE:
- This is not defined by default.
-
-DESCRIPTION:
- In case this configuration option is defined, then the support to read a
- directory is disabled in the root IMFS. It is still possible to open nodes
- in a directory.
-
-.. index:: CONFIGURE_IMFS_DISABLE_READLINK
-
-.. _CONFIGURE_IMFS_DISABLE_READLINK:
-
-CONFIGURE_IMFS_DISABLE_READLINK
--------------------------------
-
-CONSTANT:
- ``CONFIGURE_IMFS_DISABLE_READLINK``
-
-DATA TYPE:
- Boolean feature macro.
-
-RANGE:
- Defined or undefined.
-
-DEFAULT VALUE:
- This is not defined by default.
-
-DESCRIPTION:
- In case this configuration option is defined, then the support to read
- symbolic links is disabled in the root IMFS.
-
-.. index:: CONFIGURE_IMFS_DISABLE_RENAME
-
-.. _CONFIGURE_IMFS_DISABLE_RENAME:
-
-CONFIGURE_IMFS_DISABLE_RENAME
------------------------------
-
-CONSTANT:
- ``CONFIGURE_IMFS_DISABLE_RENAME``
-
-DATA TYPE:
- Boolean feature macro.
-
-RANGE:
- Defined or undefined.
-
-DEFAULT VALUE:
- This is not defined by default.
-
-DESCRIPTION:
- In case this configuration option is defined, then the support to rename
- nodes is disabled in the root IMFS.
-
-.. index:: CONFIGURE_IMFS_DISABLE_RMNOD
-
-.. _CONFIGURE_IMFS_DISABLE_RMNOD:
-
-CONFIGURE_IMFS_DISABLE_RMNOD
-----------------------------
-
-CONSTANT:
- ``CONFIGURE_IMFS_DISABLE_RMNOD``
-
-DATA TYPE:
- Boolean feature macro.
-
-RANGE:
- Defined or undefined.
-
-DEFAULT VALUE:
- This is not defined by default.
-
-DESCRIPTION:
- In case this configuration option is defined, then the support to remove
- nodes is disabled in the root IMFS.
-
-.. index:: CONFIGURE_IMFS_DISABLE_SYMLINK
-
-.. _CONFIGURE_IMFS_DISABLE_SYMLINK:
-
-CONFIGURE_IMFS_DISABLE_SYMLINK
-------------------------------
-
-CONSTANT:
- ``CONFIGURE_IMFS_DISABLE_SYMLINK``
-
-DATA TYPE:
- Boolean feature macro.
-
-RANGE:
- Defined or undefined.
-
-DEFAULT VALUE:
- This is not defined by default.
-
-DESCRIPTION:
- In case this configuration option is defined, then the support to create
- symbolic links is disabled in the root IMFS.
-
-.. index:: CONFIGURE_IMFS_DISABLE_UNMOUNT
-
-.. _CONFIGURE_IMFS_DISABLE_UNMOUNT:
-
-CONFIGURE_IMFS_DISABLE_UNMOUNT
-------------------------------
-
-CONSTANT:
- ``CONFIGURE_IMFS_DISABLE_UNMOUNT``
-
-DATA TYPE:
- Boolean feature macro.
-
-RANGE:
- Defined or undefined.
-
-DEFAULT VALUE:
- This is not defined by default.
-
-DESCRIPTION:
- In case this configuration option is defined, then the support to unmount
- file systems is disabled in the root IMFS.
-
-.. index:: CONFIGURE_IMFS_DISABLE_UTIME
-
-.. _CONFIGURE_IMFS_DISABLE_UTIME:
-
-CONFIGURE_IMFS_DISABLE_UTIME
-----------------------------
-
-CONSTANT:
- ``CONFIGURE_IMFS_DISABLE_UTIME``
-
-DATA TYPE:
- Boolean feature macro.
-
-RANGE:
- Defined or undefined.
-
-DEFAULT VALUE:
- This is not defined by default.
-
-DESCRIPTION:
- In case this configuration option is defined, then the support to change
- times is disabled in the root IMFS.
-
-.. index:: CONFIGURE_IMFS_MEMFILE_BYTES_PER_BLOCK
-
-.. _CONFIGURE_IMFS_MEMFILE_BYTES_PER_BLOCK:
-
-CONFIGURE_IMFS_MEMFILE_BYTES_PER_BLOCK
---------------------------------------
-
-CONSTANT:
- ``CONFIGURE_IMFS_MEMFILE_BYTES_PER_BLOCK``
-
-DATA TYPE:
- Boolean feature macro.
-
-RANGE:
- Valid values for this configuration parameter are a power of two (2)
- between 16 and 512 inclusive. In other words, valid values are 16, 32, 64,
- 128, 256,and 512.
-
-DEFAULT VALUE:
- The default IMFS block size is 128 bytes.
-
-DESCRIPTION:
- This configuration parameter specifies the block size for in-memory files
- managed by the IMFS. The configured block size has two impacts. The first
- is the average amount of unused memory in the last block of each file. For
- example, when the block size is 512, on average one-half of the last block
- of each file will remain unused and the memory is wasted. In contrast, when
- the block size is 16, the average unused memory per file is only 8
- bytes. However, it requires more allocations for the same size file and
- thus more overhead per block for the dynamic memory management.
-
- Second, the block size has an impact on the maximum size file that can be
- stored in the IMFS. With smaller block size, the maximum file size is
- correspondingly smaller. The following shows the maximum file size possible
- based on the configured block size:
-
- - when the block size is 16 bytes, the maximum file size is 1,328 bytes.
-
- - when the block size is 32 bytes, the maximum file size is 18,656 bytes.
-
- - when the block size is 64 bytes, the maximum file size is 279,488 bytes.
-
- - when the block size is 128 bytes, the maximum file size is 4,329,344 bytes.
-
- - when the block size is 256 bytes, the maximum file size is 68,173,568 bytes.
-
- - when the block size is 512 bytes, the maximum file size is 1,082,195,456
- bytes.
-
-.. index:: CONFIGURE_MAXIMUM_DEVICES
-
-.. _CONFIGURE_MAXIMUM_DEVICES:
-
-CONFIGURE_MAXIMUM_DEVICES
--------------------------
-
-CONSTANT:
- ``CONFIGURE_MAXIMUM_DEVICES``
-
-DATA TYPE:
- Unsigned integer (``uint32_t``).
-
-RANGE:
- Positive.
-
-DEFAULT VALUE:
- If ``BSP_MAXIMUM_DEVICES`` is defined, then the default value is
- ``BSP_MAXIMUM_DEVICES``, otherwise the default value is 4.
-
-DESCRIPTION:
- ``CONFIGURE_MAXIMUM_DEVICES`` is defined to the number of individual
- devices that may be registered in the device file system (devFS).
-
-NOTES:
- This option is specific to the device file system (devFS) and should not be
- confused with the ``CONFIGURE_MAXIMUM_DRIVERS`` option. This parameter
- only impacts the devFS and thus is only used by ``<rtems/confdefs.h>`` when
- ``CONFIGURE_USE_DEVFS_AS_BASE_FILESYSTEM`` is specified.
-
-.. index:: CONFIGURE_USE_DEVFS_AS_BASE_FILESYSTEM
-
-.. _CONFIGURE_USE_DEVFS_AS_BASE_FILESYSTEM:
-
-CONFIGURE_USE_DEVFS_AS_BASE_FILESYSTEM
---------------------------------------
-
-CONSTANT:
- ``CONFIGURE_USE_DEVFS_AS_BASE_FILESYSTEM``
-
-DATA TYPE:
- Boolean feature macro.
-
-RANGE:
- Defined or undefined.
-
-DEFAULT VALUE:
- This is not defined by default. If no other root file system configuration
- parameters are specified, the IMFS will be used as the root file system.
-
-DESCRIPTION:
- This configuration parameter is defined if the application wishes to use
- the device-only filesytem as the root file system.
-
-NOTES:
- The device-only filesystem supports only device nodes and is smaller in
- executable code size than the full IMFS and miniIMFS.
-
- The devFS is comparable in functionality to the pseudo-filesystem name
- space provided before RTEMS release 4.5.0.
-
-.. index:: CONFIGURE_USE_MINIIMFS_AS_BASE_FILESYSTEM
-
-.. _CONFIGURE_USE_MINIIMFS_AS_BASE_FILESYSTEM:
-
-CONFIGURE_USE_MINIIMFS_AS_BASE_FILESYSTEM
------------------------------------------
-
-CONSTANT:
- ``CONFIGURE_USE_MINIIMFS_AS_BASE_FILESYSTEM``
-
-DATA TYPE:
- Boolean feature macro.
-
-RANGE:
- Defined or undefined.
-
-DEFAULT VALUE:
- This is not defined by default.
-
-DESCRIPTION:
- In case this configuration option is defined, then the following
- configuration options will be defined as well
-
- - ``CONFIGURE_IMFS_DISABLE_CHMOD``,
-
- - ``CONFIGURE_IMFS_DISABLE_CHOWN``,
-
- - ``CONFIGURE_IMFS_DISABLE_UTIME``,
-
- - ``CONFIGURE_IMFS_DISABLE_LINK``,
-
- - ``CONFIGURE_IMFS_DISABLE_SYMLINK``,
-
- - ``CONFIGURE_IMFS_DISABLE_READLINK``,
-
- - ``CONFIGURE_IMFS_DISABLE_RENAME``, and
-
- - ``CONFIGURE_IMFS_DISABLE_UNMOUNT``.
+ filesystem
Block Device Cache Configuration
================================
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