User`s manual

UC-7402 User’s Manual Introduction
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Software Introduction
Software Architecture
The Linux operating system that is pre-installed in UC-7402 follows the standard Linux
architecture, making it easy to port programs that follow the POSIX standard to UC-7402. Porting
is done with the GNU Tool Chain provided by Moxa. In addition to the Standard POSIX API,
device drivers for the buzzer and CompactFlash mass storage, and Wireless LAN PCMCIA card
are also included in the UC-7402 Linux system.
AP
API
Protocol
Stack
Device
Driver
Microkernel
User Application
Daemon (Apache, Telnet, FTPD, SNMP)
Application Interface (POSIX, Socket, Secure Socket)
TCP, IP, UDP, CMP, ARP, HTTP, SNMP, SMTP
PCMCIA, CF, WLAN, RTC
Memory control, Schedule, Process
RS-232, Ethernet, PCMCIA, CompactFlash
File
System
Hardware
OS Kernel
UC-7402’s Flash ROM is partitioned into Boot Loader, Linux Kernel, Mini Root File System,
and User Root File System partitions.
In order to prevent user applications from crashing the Root File System, UC-7402 uses a specially
designed Mini File System with Protected Configuration for emergency use. This Mini File
System comes with serial and Ethernet communication capability for users to load the Factory
Default Image file. The Mini File System will only be activated if the boot loader fails to load the
User Root File System.
User AP
User Directory
(User Configuration)
Mini Root File System
Configuration
Linux Kernel & Root
HW
Boot Loader
To improve system reliability, UC-7402 has a built-in mechanism that prevents the system from
crashing. The procedure is as follows.
When the Linux kernel boots up, the kernel will mount the root file system, and then enable
services and daemons. During this time, the kernel will start searching for system configuration
parameters via rc or inittab.