Operating System Concepts: Processes, Threads, and Scheduling
CH 3 – Processes
Definition:
Process = program in execution (active); program = passive file.
Process layout:
Text (code) | Data (globals) | Heap (dynamic alloc.) | Stack (function frames).
States:
new → ready → running → waiting → terminated.
PCB (Process Control Block):
state, PC, registers, priority, memory info, I/O status, accounting.
Schedulers:
Long-term (job) → admit to memory (degree of multiprogramming); Short-term (CPU) → choose next ready process; Medium-term → swap in/out
Workshop
We say that there is a surge when the nominal voltage of 220VAC, a certain percentage goes up and stays there for a certain period of time say that there are tensions Low Low voltage when the nominal value of 220 VAC, low a percentage and maintained at that value over a period of time peaks, transients and electrical noise or transient spikes appear in the power line for example when switched on or off electric motors. It appears as a very sudden surge of very high value during a tiny period of
Read MoreEssential English Grammar: Verbs, Modals, and Structures
The Verb “To Be” in the Past Simple: Was / Were
Affirmative and Negative Forms
| Subject | Affirmative | Negative |
|---|---|---|
| I | was | wasn’t |
| You | were | weren’t |
| He/She/It | was | wasn’t |
| We/You/They | were | weren’t |
Questions
Structure: Was/Were + Subject
- Was I?
- Were You?
- Was He/She/It?
- Were We/You/They?
Existential Sentences: There Was / There Were
| Form | Singular Example | Plural Example |
|---|---|---|
| Affirmative | There was a concert. | There were ten people. |
| Negative | There wasn’t a concert. | There weren’t any people. |
The Imperative Form
Affirmative Commands
- Make a fire!
- Help me!
Negative
Read MoreGeological Time Scale, Dating Methods, and Earth History
Geological Time Periods and Key Events
Paleozoic Era
- Cambrian: Marine invertebrates with external skeletons.
- Ordovician: First vertebrates appear.
- Silurian: First jawed fish; first land plants.
- Devonian: First amphibians.
- Carboniferous: Forests of giant ferns; first reptiles.
- Permian: Pangaea forms. The climate became very dry toward the end, leading to the greatest mass extinction event.
Mesozoic Era
- Triassic: First dinosaurs; first mammals.
- Jurassic: Gymnosperm plants dominate; first birds appear.
- Cretaceous:
Heroism, Power, and Deception: Key Themes in Beowulf, Chaucer, and Hamlet
Beowulf: Heroism and Anglo-Saxon Values
Beowulf is more than a story about a brave warrior; it is a reflection of the values that shaped Anglo-Saxon society. The poem argues that a true hero must show not only strength and courage but also loyalty to others. Through Beowulf’s arrival at Heorot and his battle with Grendel, the poem demonstrates how heroism is tied to responsibility and honor. These moments highlight that personal glory is only meaningful when it serves the greater good.
Loyalty and
Read MoreJava Fundamentals: Structure, Data Types, and Casting
The basic structure of a Java program is based on the concept of classes. Every executable Java program must contain at least one class definition.
Essential Structure of a Java Program
A typical Java application follows this hierarchical structure:
Package Statement (Optional)
The very first statement in a Java source file (if present) is the package statement. It organizes classes into logical groups, preventing naming conflicts.
- Syntax:
package package_name; - Example:
package com.mycompany.app;
- Syntax:
Import
Essential Definitions of Mechanical and Pneumatic Components
Four-Stroke Engine Operation
The four-stroke engine operates through four distinct stages:
- Intake: Air enters the cylinder, mixing with atomized fuel.
- Compression: The air and fuel mixture is compressed by the upward movement of the piston.
- Power (Combustion): The burning fuel forces the piston downward with great force, producing useful work.
- Exhaust: The upward movement of the piston cleans the cylinder by expelling spent gases.
Two-Stroke Engine Mechanics
Two-stroke engines are piston engines where
Read MorePonyboy Curtis: Analyzing Teenage Identity in The Outsiders
In S.E. Hinton’s 1967 novel, The Outsiders, Hinton uses the character Ponyboy Curtis to examine the theme of teenage identity by portraying the challenges of navigating peer pressure and societal expectations. Through Ponyboy, Hinton utilizes first-person narration, setting, and language features to represent teenage identity and highlight the importance of individuality, loyalty, and self-expression.
First-Person Narration and Internal Conflict
S.E. Hinton’s use of first-person narration in The
Read MoreMalaysian Subordinate Court Jurisdiction Rules (SCA 1948)
Subordinate Court Jurisdiction: Chapter 2
Counterclaims and Monetary Limits
Section 66(1) – Sessions Court: Can hear the case even if the counterclaim is bigger than the plaintiff’s claim, but cannot award more than its own limit (e.g., max RM1 million).
Section 66(2) – High Court: Any party can apply to move the whole case to the High Court, which has no monetary limit.
Calculating Claim Value: Principal and Interest
Issue: Claim Calculation for Jurisdiction
Claim = Principal (within limit) + Interest
Read MoreMineral Properties and the Complete Rock Cycle Explained
Mineral Properties and Formation
Origin of Minerals
The origin of minerals can be:
- Within a mass of molten rock (magma), such as feldspar or olivine.
- Within solid rocks under high pressures and temperatures, such as calcite.
Properties of Minerals
- Color
- The type of light a mineral reflects when illuminated.
- Luster (Brightness)
- The way a mineral reflects light (e.g., metallic, glassy, dull).
- Hardness
- The resistance of a mineral to being scratched.
- Streak (Color of the Line)
- The color of the dust that occurs when