Intermec ck1 参照ガイド
Appendix A —
µClinux System
316
CK1 SDK Programmer’s Reference Manual
The location of the configuration scripts are the same as in Linux. The /etc
folder contains all the necessary scripts that are necessary to boot up the
device. It also includes all the other general configuration files that the
different applications like PPP, chat, and the cron uses. These files are in
Arctic, are saved to the serial Flash so that they can easily be modified, and
are then saved after booting the device.
folder contains all the necessary scripts that are necessary to boot up the
device. It also includes all the other general configuration files that the
different applications like PPP, chat, and the cron uses. These files are in
Arctic, are saved to the serial Flash so that they can easily be modified, and
are then saved after booting the device.
Root File System
The
µClinux supports a variety of different file systems, including the ones
specially designed for the embedded systems. Usually the hardware
platform used with the
platform used with the
µClinux is a combination of different physical
memory storages, which all require a different file system for efficient use.
The user application in
µClinux is compiled into a ROM file system,
which the kernel mounts at the boot time. This file system is quite simple:
a space efficient read only file system mainly used for initial RAM disks on
the installation disks. The file structure of the ROM file system is defined
in the vendor specific makefile. All the executables created from the user
applications are placed in the /bin file. The other folders created are
basically following the same structure as in regular Linux distribution.
a space efficient read only file system mainly used for initial RAM disks on
the installation disks. The file structure of the ROM file system is defined
in the vendor specific makefile. All the executables created from the user
applications are placed in the /bin file. The other folders created are
basically following the same structure as in regular Linux distribution.
The second extended file system, ext2 is the most widely used file system
in Linux systems. It is an efficient file system with fast performance and a
support for file linking. It is designed to keep data in fixed size blocks,
which is set when the file system is created. The files in the ext2 are
presented with a single inode, which each have a single number identifying
it. All the inodes for the file system are kept in an inode table so the
directories in the ext2 are simply special files that contain pointers to the
inodes of their directory entries.
in Linux systems. It is an efficient file system with fast performance and a
support for file linking. It is designed to keep data in fixed size blocks,
which is set when the file system is created. The files in the ext2 are
presented with a single inode, which each have a single number identifying
it. All the inodes for the file system are kept in an inode table so the
directories in the ext2 are simply special files that contain pointers to the
inodes of their directory entries.
The proc file system provides some useful information about the current
state of the kernel and the kernel modules. The proc is a virtual file system
providing the ability to peer into the kernel’s view of the system. It is also
mounted from the rc script to the /proc folder, which includes the
information in a plain text form.
state of the kernel and the kernel modules. The proc is a virtual file system
providing the ability to peer into the kernel’s view of the system. It is also
mounted from the rc script to the /proc folder, which includes the
information in a plain text form.
The
µClinux also contains some virtual or pseudo file systems that do not
require a block device for mounting. These systems are used by default in
the image. It includes the pipefs, which provides the entry point into the
pipe system call, the socket file system enabling the socket layers, and bdev
defining a disk boot device.
the image. It includes the pipefs, which provides the entry point into the
pipe system call, the socket file system enabling the socket layers, and bdev
defining a disk boot device.
Serial Flash File System
The
µClinux provides three main types of file systems for use in Flash
devices: CRAMFS, JFFS, and JFFS2. From these the JFFS and JFFS2
belong to the same evolution tree originally designed by Axis
Communications AB. The CRAMFS was originally developed by Linus
Torvalds and was added to the kernel source of the 2.4 series. It was
designed to be a simple read-only file system that uses compression in each
belong to the same evolution tree originally designed by Axis
Communications AB. The CRAMFS was originally developed by Linus
Torvalds and was added to the kernel source of the 2.4 series. It was
designed to be a simple read-only file system that uses compression in each