2025-11-27 Operational Systems (Ivan)

Ivan - Manages hardware, processes, users, resources - Kernel is a bridge between hardware and application - Kernel has 2 modes - Privileged mode and Restricted mode - Solves problems of differences in hardware, making API constant - printf() is a sys call - Kernel mode switching is resource expensive! - Time multiplexing - Scheduling different processes on the CPU over time - Space multiplexing - Dividing RAM and Disk space among processes and users - Isolation used for not starving between processes - Program vs process - static exe on disk vs a program is executed instructions in RAM - Context switching - halts a process and switches to the other one, PCB - OS does memory management, and does protection against fragmentation - Seqfault - happens when OS tries to access a point in a memory that is not available in mapping in TLB - TLB - Cache that holds the translation table - Hardware MMU part of a processor that does the translation dig to vir and other way around.