> For the complete documentation index, see [llms.txt](https://open-mainframe-project.gitbook.io/mainframe-open-education-project/llms.txt). Markdown versions of documentation pages are available by appending `.md` to page URLs; this page is available as [Markdown](https://open-mainframe-project.gitbook.io/mainframe-open-education-project/chapter-2-mainframe-101-foundational-technology.md). # Chapter 2: Mainframe 101 - Foundational Technology As of now we already know what a mainframe is, as a next step we have prepared a section for those of you that are looking for guidance about mainframe architecture and software. The objective of this session is to share with you the initial information about the mainframe components, architecture foundational concepts, how and from where you should start. Before proceeding further, let's understand more about the components and architecture of mainframe machines: ### Hardware Resources: #### Central Processor (CP) The part of computer that contains the sequencing and processing for: * Instruction execution: Fetching instructions from memory and decoding these instructions to understand the required action and then executes the decoded instructions using its arithmetic and logic unit (ALU). * Initial program load: During IPL, the CP loads the operating system into the main memory and starts various system services for the smooth working and operation of mainframe. * Others machine operations. #### Physical Storage: * Central storage is the primary storage located within the processor complex. It is directly accessible by the Central Processing Unit (CPU) for executing instructions and processing data. * Auxiliary storage, external to the processor and includes various types of non-volatile storage media. #### Logical Partitions (LPARs): Mainframes are typically divided into Logical Partitions (LPARs), which are subsets of the computer's hardware resources virtualized as separate computers with its own set of hardware resources, such as CPU, memory, and I/O channels. A physical machine can be partitioned into multiple LPARs, each housing a separate operating system. For example, one LPAR might run z/OS while other runs z/VM. ### System Peripherals: * Hardware Master Console (HMC): Controls mainframe hardware . * Manages logical partitions (LPARs). * Controls system initialization, configuration, and operational tasks. * Operator console: Controls and operates z/OS operating systems. * Auxiliary Storage Devices. ### Software and additional mainframe components: ### Operating Systems: Software that controls the running of programs; in addition, operating system may also provide services like resource allocations, scheduling and data management. * **z/OS:** The primary operating system for IBM mainframes, designed for high availability, security, and scalability. * **z/VM:** A hypervisor (virtual machine monitor) that allows multiple virtual machines to run on a single mainframe where each VM can run its own operating system. * **z/VSE:** An operating system for small and medium-sized mainframe environments used for batch processing and transaction processing. #### IBM WebSphere Application Server: An IBM transaction processing facility for processing messages to/from web services. #### Enterprise Security Management (ESM): Software that provides access control and auditing functionality for z/OS and z/VM operating systems. ### Utilities and Tools: #### JCL (Job Control Language): Scripting language for defining and controlling batch jobs on z/OS. In mainframe systems, "batch" refers to a method of processing set of tasks or programs without requiring user interaction in real-time. #### Time Sharing Option (TSO): An operating system facility to enable users to share computer time and resources. **ISPF (Interactive System Productivity Facility):** Provides a better interface for managing z/OS resources, dataset management, and job submission. It offers a more user-friendly interface compared to the command-line interface of TSO. It was an overview to the components and technology used in mainframe systems before we could move to next part and dive deeper into it. --- # Agent Instructions This documentation is published with GitBook. GitBook is the documentation platform designed so that both humans and AI agents can read, navigate, and reason over technical content effectively. 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