Read-Only File System Romfs | Moxa Technologies UC-7110 manual

Moxa Technologies UC-7110 Read-Only File System Romfs, Journaling Flash File System JFFS2

UC-7110 Series User’s Manual

Software Package

and uses JFFS2 for the User Directory.

The partition sizes are hard coded into the kernel binary. You must rebuild the kernel to change the partition sizes. The flash memory map is shown in the following table.

Flash Context	Flash Address	Size		Access control
Boot loader	0 – 0x3ffff	256 K		Read ONLY

Kernet &	0x40000– 0x3fffff	4	M - 256 K	Read ONLY
Root File System	0x40000– 0x3fffff	4	M - 256 K	ROMFS
Root File System				ROMFS

User Directory	0x400000 – 0x7fffff	4	M	Read / Write
User Directory	0x400000 – 0x7fffff	4	M	JFFS2
				JFFS2

In addition to the flash file systems, a RAM based file system will be mounted on /var/.

Read-Only File System (ROMFS)

ROMFS is a read-only file system for Linux. This means that it is a non-journaling file system. Unlike CRAMFS, ROMFS does not support code compression.

A working Linux system requires the kernel and at least some programs, so obviously a file system is also needed. Most Linux disk file systems are designed to be high performance, supporting all POSIX features, and sometimes elaborate recovery from crashes (journaling). This makes the system quite heavy-weighted, and thus often inappropriate for some special purposes.

Additional information about ROMFS is available at:

http://romfs.sourceforge.net/

Journaling Flash File System (JFFS2)

The flash User Directory is formatted by the Journaling Flash File System (JFFS2), which places a compressed file system on the flash, transparent to the user.

The Journaling Flash File System (JFFS2) was developed by Axis Communications in Sweden.

JFFS2 provides a file system directly on flash, rather than emulating a block device designed for use on flash-ROM chips, and it recognizes flash-ROM chips' special write requirements, does wear-leveling to extend flash life, keeps the flash directory structure in RAM at all times, and implements a log-structured file system that is always consistent—even if the system crashes or unexpectedly powers down. It does not require fsck on boot up.

JFFS2, the next version of JFFS, provides improved wear-leveling and garbage-collection performance, improved RAM footprint and response to system-memory pressure, improved concurrency and support for suspending flash erases, marking of bad sectors with continued use of the remaining good sectors (thus enhancing the write-life of the devices), native data compression inside the file system design; and support for hard links.

Key features of JFFS2 are:

yDirectly targeted to Flash ROM

yRobust

yConsistent across power failure

yNo integrity scan (fsck) is required at boot time after normal or abnormal shutdown

yExplicit wear leveling

yTransparent compression

3-3

UC-7110 specifications

The Moxa Technologies UC-7110 is a powerful and versatile computing platform designed for industrial applications and IoT (Internet of Things) deployments. It represents a compelling solution for edge computing needs, with an emphasis on reliability, flexibility, and ease of integration. The UC-7110 offers a compact form factor, making it suitable for space-constrained environments while delivering robust performance.

One of the UC-7110's main features is its Intel Atom E3825 processor, which provides a balance of power efficiency and computational capability, ensuring it can handle the demands of data processing tasks at the edge. With 1GB of DDR3 RAM and support for up to 32GB of onboard eMMC storage, the UC-7110 can efficiently manage applications that require quick access to data without the need for extensive external storage devices.

The UC-7110 also stands out for its extensive connectivity options. It is equipped with multiple serial ports, digital input/output (DIO), USB ports, and Ethernet interfaces, allowing seamless integration with a wide range of industrial devices and protocols. This connectivity is crucial for real-time data acquisition and control in various industrial settings. The device also supports optional wireless communication modules, including LTE, Wi-Fi, and Bluetooth, enhancing its suitability for remote and mobile applications.

In terms of software capabilities, the UC-7110 operates on a Linux-based operating system, providing users with the flexibility to develop custom applications tailored to their specific needs. Moxa also provides the MXIO library, which simplifies the programming of input/output operations, making it easier for developers to create robust and responsive applications.

The UC-7110 is designed to endure harsh industrial environments, featuring wide operating temperature ranges from -40°C to 70°C and IP30-rated protection against dust and moisture. This ruggedness ensures reliable performance in challenging conditions, which is critical for industries such as manufacturing, transportation, and energy.

Additionally, the device supports various industrial protocols like Modbus, MQTT, and OPC UA, facilitating integration into existing systems and enabling efficient data communication across different platforms. This compatibility is vital for leveraging existing infrastructure while adopting modern IoT solutions.

In summary, the Moxa UC-7110 is a robust, versatile edge computing solution ideal for industrial IoT applications. Its combination of powerful processing, extensive connectivity options, software flexibility, and rugged design makes it a valuable asset for organizations seeking to enhance their operational efficiency and adapt to evolving technological demands. Whether in manufacturing, smart cities, or remote asset monitoring, the UC-7110 provides the necessary tools to unlock new possibilities in industrial connectivity and data management.