IBM AS/400E manual

Chapter 8. Integrated File System APIs and the Network File System

Error Conditions

There are two error conditions that commonly appear when working with the Network File System through integrated ®le system APIs (application program interface) that require special consideration. These error conditions are the ESTALE and EACCES error conditions.

ESTALE Error Condition

The return of this error number means that the server has rejected the ®le or object handle.

If you are accessing a remote ®le through the Network File System, the ®le may have been deleted at the server. Or, the ®le system that contains the object may no longer be accessible.

EACCES Error Condition

The return of this error number means that the server denies permission to the object.

A process or job made an attempt to access an object in a way that the object access permissions forbid.

The process or job does not have access to the speci®ed ®le, directory, component, or path.

If you access a remote ®le through NFS, the client will not re¯ect any ®le permissions at the client until local data updates occur. There are several options to the Add Mounted File System (ADDMFS) and MOUNT commands that determine the time between refreshes of local data. Access to a remote ®le may also fail due to different UID or GID mapping on the local and remote systems.

API Considerations

When using APIs that either create or remove ®les, there are considerations that deal with the throughput of the NFS server. If a server is busy, a client making requests can timeout and send the same requests multiple times to the server. Because of this, clients may receive either the EEXIST or ENOENT error conditions when they create or remove ®les using APIs. These error conditions may appear even though the operation completely successfully.

User Datagram Protocol (UDP) Considerations

To create or remove a ®le, the client sends a request to the server. If the server is busy, the client may timeout a number of times before the server completes the original request. The underlying UDP support of the NFS protocol may incorrectly handle these multiple requests.

AS/400E specifications

The IBM AS/400E, now more commonly known as IBM i, is a robust and versatile midrange server that has been designed to provide a comprehensive computing solution for businesses of all sizes. First introduced in the late 1980s, the AS/400 series has undergone multiple enhancements and rebranding, with the AS/400E being one of the notable iterations. This powerful platform is closely associated with IBM's commitment to reliability, scalability, and integrated business solutions.

One of the main features of the AS/400E is its highly integrated architecture that combines hardware and software into a cohesive system. This integration allows for seamless operations, reducing the complexity typically associated with managing disparate systems. The system is powered by IBM's proprietary OS/400 operating system, which has evolved into IBM i, featuring advanced capabilities like object-oriented programming, integrated database management, and security features that are essential for enterprise environments.

A key characteristic of the AS/400E is its robust database support, primarily through the use of DB2 for i. This integrated database management system enables efficient data handling and retrieval, facilitating real-time business analytics and reporting. Furthermore, the platform supports a variety of programming languages, including RPG, COBOL, and Java, making it flexible for developers who require diverse tools for application development.

The AS/400E is also known for its exceptional reliability and uptime, making it a preferred choice for critical business applications in industries such as finance, healthcare, and manufacturing. This reliability is backed by advanced error detection and correction mechanisms, as well as redundancy features that help prevent data loss and minimize downtime.

In terms of scalability, the AS/400E can effortlessly expand to accommodate growing business demands. Organizations can increase processing power by adding more resources without significant disruption. This scalability, combined with the system’s built-in virtualization capabilities, allows businesses to optimize resource usage and streamline operations.

Security is another defining feature of the AS/400E. The platform incorporates various layers of security measures, including user authentication, encryption, and comprehensive auditing capabilities, ensuring that sensitive business data is protected against unauthorized access.

Overall, the IBM AS/400E remains a powerful tool in the enterprise computing landscape, providing businesses with an integrated, reliable, and secure solution for their technological needs. Its enduring popularity is a testament to its capability to evolve with changing business requirements while maintaining its core attributes of high performance and stability.

IBM AS/400E manual Integrated File System APIs and the Network File System

Models: AS/400E