Midterm 1 - Comprehensive Review Cheatsheet

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Midterm 1 - Comprehensive Review Cheatsheet

Part 1: OS Fundamentals (Lecture 1)

What is an OS?

Application Benefits of an OS

User Benefits of an OS

Three Big Ideas

Part 2: Processes (Lecture 2)

Process vs Program

Process State

Process Creation: fork() and exec()

fork() Details

How to Count fork() Output

How to Trace fork() Output

Limited Direct Execution

System Calls Mechanism

Context Switch Steps

Cooperative vs True Multitasking

Hardware vs OS Responsibilities

Part 3: Scheduling (Lectures 3-4)

Metrics

Scheduling Policies Summary

How to Solve Scheduling Problems

FIFO

SJF (Non-Preemptive)

STCF (Preemptive)

Round Robin

Identifying Schedulers from Gantt Charts

Round Robin Time Slice Tradeoffs

MLFQ Rules

MLFQ vs STCF

CFS (Completely Fair Scheduler)

Multiprocessor Scheduling

Part 4: Memory Virtualization Mechanisms (Lectures 5-6)

Address Space Layout

Where Things Live

Key Memory Concepts

Memory Hierarchy

Five Memory Virtualization Approaches

Static Relocation

Base + Bounds

Reverse Engineering Base+Bounds from Traces

Segmentation

Segmented Paging — Combined Translation with Permission Check

Segmentation Disadvantages

Part 5: Paging (Lectures 6-7)

Paging Basics

Key Formulas

Common Page Sizes

Page Table Entry (PTE) Contents

Address Translation with Paging

Paging Doubles Memory References

Linear Page Table Size Calculation

Comparing Memory Reference Counts

Part 6: TLB (Lectures 6-7)

TLB Basics

TLB Miss Rate Calculations

TLB Reach

TLB and Locality

TLB and Context Switches

TLB Contents After Execution

Part 7: Multi-Level Page Tables (Lecture 7)

Why Multi-Level?

Key Formulas

Number of Levels Calculation

Multi-Level Page Table Walk

Page Table Walk from Hex Memory Dump

Multi-Level Space Calculation

x86-64 Page Tables (4 levels)

Memory Reference Counting

Part 8: Paging with Segments

Concept

Part 9: Beyond Physical Memory (Lectures 8-9)

Page Locations

Demand Paging

Page Fault Handling Steps

Copy-on-Write (COW)

Shared Memory

Inverted Page Tables

Part 10: Page Replacement (Lectures 8-9-10)

Page Replacement Policies

How to Trace Page Replacement

FIFO Trace

LRU Trace

OPT Trace

Belady’s Anomaly

Clock Algorithm (Approximate LRU)

LRU Implementation Difficulty

Additional Page Replacement Facts

Working Set

Thrashing

Part 11: Memory-Mapped Files

Part 12: Quick-Reference True/False Gotchas

Process State After Fork + I/O

Part 13: Calculation Quick Reference

Page Table Sizing Cheat Sheet

Scheduling Cheat Sheet

TLB Miss Rate Cheat Sheet

Memory References Cheat Sheet

Fork Cheat Sheet