OBJ1.pptVIP

Operating System Simulator Project Purpose Basic concepts of event driven simulation Operating System Concepts Resource allocation and management context switching and interrupt handling Basic flow of control with in OS Fundamental data structures Operating System Simulator Project Program will simulate the action of both hardware and software components Hardware CPU Memory Peripheral devices Interrupt Handler Software CPU scheduler Process management functions Operating System Simulator Project Input files System configuration File CONFIG.DAT User logon File LOGON.DAT Process File SCRIPT.DAT Program files EDITOR.DAT PRINT.DAT COMPILER.DAT LINKER.DAT Operating System Simulator Project Simulator Overview The simulator is based on events Begins by processing events, generates more events during the progress and processes the generated events Normally starts with LOGON events Interrupt hardware Changes the CPU and memory states Calls Interrupt handler Services the interrupt OSSIM – Major Data Structures Major Data Structures OSSIM – Major Data Structures OSSIM -Minor Data Structures Big Picture: Process Mgmt Big Picture: IO Mgmt Big Picture: Memory Mgmt OSSIM – Objective 1 LOGON.DAT EVENT,AGENT,TIME EVENT An event in a computer system is a change of system state LOGON, SIO, WIO, END, and EIO Should be able to handle event names in both upper an lower cases AGENT Two types User (Terminal) format: Uxxx Device Format: disk1, printer TIME Unsigned long decimal OSSIM – Objective 1 Void Add_event(struct simtime *time, int event, int agent ) This function inserts a future event in the list new_events in the proper time sequence.new_events points to the end of the list having the smallest time defined by the given function: Cmpr_time(struct simtime * , struct simtime *) OSSIM – Objective 1 Directions: This function is called by Load_events(void) Use the structure event_type with the given simtime, agent, and event. /* The event list is a doubly-linked