Intermec ck1 参照ガイド
Appendix A —
µClinux System
CK1 SDK Programmer’s Reference Manual
315
Typically the Flash partition under the
µClinux holds the bootloader and
some other configurations at the beginning and the rest of the Flash
reserved to the Linux image. The following illustration shows a typical
Flash partition.
reserved to the Linux image. The following illustration shows a typical
Flash partition.
Bootloader
Vendro Settings
Kernel
Root File System
Typical Flash Partition Arrangement of
µClinux Platform
The solution of placing the kernel and the root file system in the Flash has
several options with their advantages and disadvantages. In Arctic, the
kernel and root file system are concatenated together and placed as a
compressed image to the Flash. From there, at the boot, the image is
decompressed and placed to the RAM. For configuration and file saving,
the Arctic provides a separate serial Flash chip. From the root file system,
the most important and changed folders like /etc can be linked to the
point in the serial Flash.
several options with their advantages and disadvantages. In Arctic, the
kernel and root file system are concatenated together and placed as a
compressed image to the Flash. From there, at the boot, the image is
decompressed and placed to the RAM. For configuration and file saving,
the Arctic provides a separate serial Flash chip. From the root file system,
the most important and changed folders like /etc can be linked to the
point in the serial Flash.
Another option is to place the kernel and the root file system as separate
files in the storage. This way the updating of one of these pieces is easier
and does not require of compiling and loading the whole image again. It
also makes it possible that the root file system is kept in the Flash as it is,
so all of the modifications will automatically be saved. The kernel in this
option can be kept in a compressed form in the Flash and from there
decompressed to the RAM. This option requires some hacking as the
crt0_ram.S for processors always tries to relocate an attached romfs after
the .bss section. The solution for this is either to modify the crt0_ram.S or
just to create a pseude-romfs image file that the code can locate.
files in the storage. This way the updating of one of these pieces is easier
and does not require of compiling and loading the whole image again. It
also makes it possible that the root file system is kept in the Flash as it is,
so all of the modifications will automatically be saved. The kernel in this
option can be kept in a compressed form in the Flash and from there
decompressed to the RAM. This option requires some hacking as the
crt0_ram.S for processors always tries to relocate an attached romfs after
the .bss section. The solution for this is either to modify the crt0_ram.S or
just to create a pseude-romfs image file that the code can locate.
Like in the regular Linux, the initialization continues to detect and
initialize the hardware. It sets up the interrupts and loads the necessary
drivers for these devices. After the hardware is set up, the kernel executes
the init, which then reads the system inittab file. Next, the init executes
the start script, which holds applications that are executed only once at the
boot. To finalize the boot process, the
initialize the hardware. It sets up the interrupts and loads the necessary
drivers for these devices. After the hardware is set up, the kernel executes
the init, which then reads the system inittab file. Next, the init executes
the start script, which holds applications that are executed only once at the
boot. To finalize the boot process, the
µClinux runs the rc script, which
contains the commands that need to be run for the device to work. The
script normally mounts the necessary file systems and assigns the network
addresses.
script normally mounts the necessary file systems and assigns the network
addresses.