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Similar to Operating systemMINIX GitHub: https://github.com/Stichting-MINIX-Research-Foundation/minix Description: The MINIX operating system served as the basis for Tanenbaum’s book and is a microkernel OS designed for teaching. (20)
Operating systemMINIX GitHub: https://github.com/Stichting-MINIX-Research-Foundation/minix Description: The MINIX operating system served as the basis for Tanenbaum’s book and is a microkernel OS designed for teaching.
- 2. Operating System An Operating System (OS) is system software that manages computer hardware and software resources . It acts as an intermediary between users and the computer hardware.
- 3. Functions of an Operating System: 1.Process Management – Handles the execution of processes, including multitasking, scheduling, and termination. 2.Memory Management – Allocates and manages RAM usage by different applications. 3.File System Management – Organizes, stores, retrieves, and secures files and directories. 4.Device Management – Controls and coordinates hardware components like printers, disks, and input devices.
- 4. System and application program Operating system Computer hardware User 1 User 2 User 3 User n compil er assem ble Text editor Database system
- 5. Computer components 1. Hardware Provides basic computing resources . For example: ( CPU, memory, I/O devices) 2. Operating system Controls the use of the hardware among the various application programs for the various users 3. Applications programs Define the ways in which the system resources are used to solve the computing problems of the users . 4. Users people, machines, other computers
- 6. User View in an Operating System •Varies by Interface Depends on the type of system used. •Ease of Use & Resource Utilization Balances usability and efficient resource sharing. •Mainframe/Minicomputer Users Multiple users access the same system via terminals, sharing resources and information. •Workstations & Networks Users have both dedicated and shared resources within a network. •Handheld & Standalone Devices Focus on individual usability with limited resource sharing.
- 7. View in an Operating System •Resource Allocator Manages and allocates resources efficiently among programs and users. •Conflict Management Resolves conflicting resource requests to maintain system efficiency. I/O & User Program Management Oversees input/output devices and user processes. Control Program Prevents errors and ensures smooth execution of user programs and system operations. •Goal Simplifies computing by executing programs efficiently and making the system usable.
- 8. System view Conflict Resolution Handles multiple, conflicting resource requests. •System Efficiency Ensures optimal operation of programs and users. •I/O & Program Management Oversees input/output devices and user programs. •Control Program Prevents errors and improper system use.
- 9. Defining Operating Systems OS Functionality Simplifies computing, making it user-friendly. •Resource Allocator Manages and distributes system resources. •Control Program Oversees execution of programs and I/O operations. •Kernel The core OS program always running, while other programs are applications.
- 11. Computer-System Operation •CPU (One or More) Performs logical and mathematical calculations. •Device Controllers Manage specific devices (e.g., disk drives, audio devices). •Common Bus Facilitates access to shared memory.
- 12. Computer Startup Process & Interrupts •Bootstrap Program Runs at startup, stored in firmware (EEPROM). Initializes system and loads the OS. •Kernel Must be loaded into memory. •Interrupts Triggered by hardware, sending a signal to the CPU via the system bus. .Software Interrupts Also known as system/monitor calls. CPU pauses execution and jumps to a predefined address. Interrupt vector: Stores addresses mapped to device-specific interrupt service routines.
- 13. Storage Structure & Instruction Execution •Main Memory (RAM) Stores computer programs temporarily. Only storage directly accessible by the CPU. DRAM: Each word has its own address. •Instruction Execution Cycle Fetch instruction from memory. Store in instruction register. Decode the instruction. Execute the instruction. Store result in memory. •Limitations of Main Memory Too small to store all programs and data. Volatile (loses data when power is off).
- 14. Storage Structure •Semiconductor Memory Fast and cost-effective. •Volatile Storage Loses data when power is off. •Non-Volatile Storage Retains data without power. •Electronic Disk Can be either volatile or non-volatile. •Flash Memory Removable storage for general-purpose computers. •NVRAM (Non-Volatile RAM) DRAM with battery backup.
- 16. I/O Structure •Device Controllers & Bus Connected through a common bus; may control multiple devices. •Example A SCSI controller can manage 7+ devices. •Role of Device Controller Moves data between peripherals and its local buffer. •Device Driver OS has a specific driver for each controller. I/O Operation (Small Data Transfers) 1.Device driver configures registers in the device controller. 2.Controller determines the required action. 3.Data moves from the device to the controller's buffer. 4.Controller notifies the driver when done. 5.Driver returns control to the OS. Bulk Data Transfers (Direct Memory Access - DMA) Setup: Buffers, pointers, and counters are configured. Execution: Controller transfers entire data blocks between its buffer and memory. Efficiency: Only one interrupt per block; CPU remains free for other tasks.