TCP/IP: Architecture, Protocols and Implementation
TCP/IP: Architecture, Protocols and Implementation
Multiple-logical-channel subsystems: increasing zSeries I/O scalability and connectivity
IBM Journal of Research and Development
IBM System z9 open systems adapter for communication controller for Linux
IBM Journal of Research and Development
Practical software reuse for IBM System z I/O subsystems
IBM Journal of Research and Development
Libra: a library operating system for a jvm in a virtualized execution environment
Proceedings of the 3rd international conference on Virtual execution environments
FCP for the IBM eServer zSeries systems: access to distributed storage
IBM Journal of Research and Development
IBM system z10 open systems adapter ethernet data router
IBM Journal of Research and Development
Scalable I/O - a well-architected way to do scalable, secure and virtualized I/O
WIOV'08 Proceedings of the First conference on I/O virtualization
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In recent years the capacity of mainframe-class servers has grown, and the quantity of data they are required to handle has grown with them. As a result, the existing S/390® I/O architecture required modifications to support an order of magnitude increase in the bandwidth. In addition, new Internet applications increased the demand for improved latency. Adapters were needed to support more users and a larger number of connections to consolidate the external network interfaces. The combination of all of the above requirements presented a unique challenge to server I/O subsystems. With the introduction of the zSeries™ comes an enhanced version of a new I/O architecture for the mainframe called queued direct I/O (QDIO). The architecture was initially exploited for Gigabit and Fast Ethernet adapters. More recently the architecture was exploited by the OSA-Express network adapter for Asynchronous Transfer Mode (ATM) and high-speed Token Ring connections, and it was exploited by HiperSockets for internal LPAR-to-LPAR connections. In each of these features, the TCP/IP stack is changed to tightly integrate the new I/O interface and to offload key TCP/IP functions to hardware facilities. For external communications, the offloaded functions are performed by the OSA-Express hardware microcode; for internal communications, the offloaded functions are performed in the zSeries Licensed Internal Code (LIC). The result is a significant improvement in both latency and bandwidth for sockets-based messaging which is transparent to the exploiting applications.