IBM zEnterprise System Channel Architecture and I/O Operations

This course provides an overview of current IBM System z family of servers. It gives detailed information on the System z channel architecture, System z High Performance FICON, (zHPF), Fiber connection (FICON) and Enterprise Systems Connection (ESCON) channels. It lists operational and protocol characteristics and use of available tools for problem determination (PD) purposes. It discusses operator commands, directors, and Hardware Management Console (HMC)/Support Element (SE) usage for channel problem determination and resolution. Also discussed is the I/O operations component of System Automation (SA) for z/OS (SA z/OS), its purpose and how it is used to manage and assist in PD for large enterprises with FICON and ESON configurations. Hands on lab exercises are included to reinforce lecture topics.

The course describes how the OS initiates an I/O request, passes it to the channel subsystem (CSS) and identifies the flow through the CSS, control blocks used, and the associated FICON or ESCON channel path components to the target I/O device. It compares the operation of zHPF capable channels using command mode and transport mode, describing the differences in the channel program command structure and operation. Operational and protocol differences are identified between zHPF, FICON, and ESCON architecture used by the System z servers.

System z channel subsystem enhancements such as: System z high performance FICON (zHPF) architecture, persistent information unit (IU) pacing for extended distances, FICON channel-to-channel (CTC) capabilities and FICON cascaded director support are discussed in detail. Channel operation and performance between ESCON and FICON are compared and discussed.

The course describes FCS FC-SB missing information unit detection, retry and recovery sequences, channel path problems and what type of indications surface potential trouble areas and corrective action. Operator messages and indications on the z/OS console, Hardware Management Console, (HMC) and SE will be shown. HMC and z/OS command usage will be identified to display current FICON channel and path status.