Power Button → PSU mulai menyalurkan daya.
Firmware (UEFI/BIOS) → menginisialisasi komponen hardware.
POST (Power-On Self Test) → mengecek apakah komponen penting ada dan berfungsi.
Select Boot Device → UEFI memilih perangkat tempat OS berada sesuai boot order.
Bootloader → memuat Operating System dari storage ke RAM, lalu kontrol sistem diserahkan ke OS.

What happens first when you press the power button?

The PSU starts delivering power to components

What is UEFI's role in the boot process?

It initializes and coordinates hardware components

What does POST check for?

Whether required hardware is present and working

How does UEFI know which device to boot from?

It follows a configured boot priority list

What does the bootloader do?

Loads the operating system into RAM

Press Power Button: You press the power button, sending a signal to the PSU to let power through. The system begins powering up.
Firmware Starts (UEFI/BIOS): UEFI (or older BIOS) firmware initializes and coordinates components. It's the first software that runs.
Power-On Self Test (POST): UEFI runs POST to check that required hardware is present, configured, and functioning. Errors trigger beeps or alerts.
Select Boot Device: UEFI follows a priority list to determine which device to boot from - typically an SSD or HDD with the OS installed.
Initiate Bootloader: The bootloader loads the operating system into RAM. Then UEFI hands control to the OS, completing the boot sequence.

What is the flag that you received after completing the exercise?

THM{pc5ucce55fully5t4rt3d}

Computer Types

Sophia's Summer of Hidden Computers - Month 1

Laptop → portabel, cocok untuk aktivitas sehari-hari seperti email dan dokumen.
Desktop → dipakai di lokasi tetap, punya pendinginan dan performa berkelanjutan yang lebih baik.
Workstation → untuk pekerjaan profesional berat seperti simulasi dan 3D, mengutamakan akurasi dan reliability.
Server → biasanya tidak punya screen/keyboard untuk penggunaan langsung; menyediakan layanan ke banyak pengguna melalui network dan dapat berjalan terus-menerus.
Which computer type usually runs without a dedicated screen and keyboard?

server

What kind of computer with specialized components would one buy to carry out precision work?

workstation

Sophia’s Summer of Hidden Computers – Month 2

Smartphone → komputer kecil di saku, fokus pada baterai dan konektivitas.
Tablet → komputer layar sentuh dengan ukuran lebih besar.
IoT device → perangkat khusus yang terhubung ke jaringan, misalnya smart doorbell atau fitness tracker.
Embedded computer → komputer yang tertanam di dalam perangkat lain untuk menjalankan fungsi tertentu.
What is the currently most popular pocket-sized computer?

smartphone

What kind of computer would you expect to find in a coffee machine?

embedded computer

Why Computers Come in Different Flavors

1

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2

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3

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4

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5

Why do laptops throttle more than desktops?

Less cooling space

What does server redundancy prevent?

single points of failure

Why do smartphones last longer on battery than laptops?

Optimized for efeciency

Which feature is more common in workstations?

ECC RAM & Certified drivers

In many smart homes, what coordinates devices?

Hub or cloud service

ANSWER

Go through the attached static site and get the flag.

THM{8_computer_types}

Client-Server Basics

Pizza Delivery

Client → pihak yang memulai permintaan, misalnya browser.
Server → sistem yang menerima permintaan dan memberikan layanan/data.
Request → permintaan dari client ke server.
Response → jawaban dari server ke client.
Protocol → aturan komunikasi antara client dan server, termasuk format, syntax, command, dan jenis response.
Port → “pintu” untuk mengakses layanan tertentu pada server. Satu server bisa punya banyak layanan dengan port berbeda.
DNS → menerjemahkan nama domain seperti example.com menjadi IP address.
IP address → alamat suatu sistem di jaringan.
What do we use to identify a specific service on a server?

Port

What do we call the address of a server?

internet Protocol Address

Web Communication in Practice

HTTP/HTTPS adalah protokol client-server untuk komunikasi di web.
HTTP bersifat stateless, artinya tiap request diproses secara terpisah.
Agar login tetap “diingat”, website biasanya memakai session, cookie, atau token.

Ada 9 method utama HTTP: GET, POST, PUT, DELETE, PATCH, HEAD, OPTIONS, CONNECT, TRACE.

Yang dibahas di sini adalah GET:

Dipakai untuk mengambil resource/data dari web server.
Contoh: GET https://tryhackme.com/index.php

Field penting saat melihat request:

Scheme → HTTP atau HTTPS.
Host → server/domain tujuan.
Filename → file/resource yang diminta.
Address → IP address server.
Status → hasil request, misalnya 200 OK = berhasil.

Response dari server terdiri dari:

Response Header → metadata tentang response.
Response Body → isi/resource yang diminta, misalnya HTML halaman web.

Yang paling penting diingat: GET = mengambil data, dan 200 OK = request berhasil.

What would be the host in the following URL? https://www.iamlearning.thm/contact

www.iamlearning.thm

What would be the scheme in the following URL? https://www.iamlearning.thm/contact

https

Virtualisation Basics

Virtualisation Overview

Intinya:

Dulu umum dipakai konsep “1 server = 1 aplikasi”.
Masalahnya: mahal, banyak resource terbuang, deployment lambat, dan sulit scale.
Virtualization memungkinkan satu server fisik menjalankan beberapa komputer virtual sekaligus.
Hypervisor adalah software yang membagi dan mengatur resource hardware untuk tiap VM.
Setiap VM (Virtual Machine) punya OS, aplikasi, dan konfigurasi sendiri, seolah-olah komputer terpisah.

Analogi gedung:

Gedung = physical server
Apartemen = VM
Penghuni = aplikasi/OS
Pengelola gedung = hypervisor

Yang paling penting diingat: virtualization membuat satu hardware fisik bisa dipakai banyak sistem secara terpisah, aman, dan lebih efisien.

What does virtualization enable multiple applications to share?

physical server

What is the name of the software that manages the resources for each lab machine?

Hypervisor

Virtualization Components

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Hypervisor = software yang membuat dan mengelola VM.
Tugasnya membagi CPU, RAM, storage, menjaga isolasi, dan mengatur lifecycle VM seperti start, stop, pause, clone, dan delete.

Perbedaan hypervisor:

Type 1 → langsung berjalan di hardware fisik. Cocok untuk server produksi, database, data center.
Type 2 → berjalan di atas OS utama. Cocok untuk belajar, testing, Kali Linux, dan lab malware.

VM (Virtual Machine):

Punya virtual CPU, RAM, storage, network, dan OS sendiri.
Lebih terisolasi.
Contoh software Type 2: VirtualBox dan VMware Workstation.

Container:

Lebih ringan daripada VM.
Biasanya menjalankan satu aplikasi beserta dependencies-nya.
Berbagi kernel dengan host, jadi tidak membawa OS lengkap sendiri.
Start lebih cepat dan memakai resource lebih sedikit.
Contoh platform: Docker.

Perbedaan paling penting: VM = punya OS sendiri, sedangkan container = berbagi kernel host.

Analogi:

Physical server = gedung
VM = apartemen
Container = kamar di dalam apartemen
Hypervisor = pengelola gedung

Suppose a user wants to deploy a study lab on their machine to practice some exercises for a cyber security certification. Which type of hypervisor will they use?

type 2

Suppose a company wants to host multiple small applications in the same lab machine. What should they use?

containers

Managing Virtual Machines

What is the name of the lab machine that has been running for the longest time?

Monitoring-SYS

What is the name of the lab machine that is using the biggest amount of memory?

DB-Cluster-01

How many VMs are in the running state after you solved the issue on Mail-SERVER?

8

What is the name of the physical machine that is hosting most of the VMs?

HV-PROD-02

Cloud Computing Fundamentals

Cloud Computing Overview

Cloud computing = menggunakan server, storage, dan resource komputasi melalui internet, bukan hanya dari satu komputer lokal.
Keunggulan utama:
- Scalable → resource bisa dinaikkan atau diturunkan sesuai kebutuhan.
- On-demand → server/storage bisa dibuat kapan saja.
- Pay-as-you-go → bayar sesuai pemakaian.
- High availability → layanan tetap tersedia meski sebagian sistem gagal.
- Global access → bisa diakses dari mana saja.
- Security → infrastruktur diamankan oleh cloud provider.

Tipe deployment:

Public Cloud → murah, mudah scale, cocok untuk kebanyakan aplikasi.
Private Cloud → kontrol dan compliance lebih tinggi, cocok untuk data sensitif.
Hybrid Cloud → gabungan private dan public cloud.

Model layanan:

IaaS → provider mengurus hardware, kamu mengurus OS dan aplikasi.
PaaS → provider juga mengurus OS, kamu fokus ke aplikasi.
SaaS → semuanya dikelola provider, kamu tinggal memakai aplikasinya.

Contoh:

IaaS → virtual server/cloud VM.
PaaS → platform untuk deploy aplikasi.
SaaS → Gmail, Zoom.

Cloud provider yang disebut: AWS, Microsoft Azure, GCP, Alibaba Cloud, IBM Cloud, Oracle Cloud.

Yang paling penting diingat: IaaS = paling banyak kontrol, PaaS = fokus ke aplikasi, SaaS = tinggal pakai.

What is the characteristic of cloud environments that enables you to handle an unexpected increase in access to your application?

Scalability

What is the most common type of cloud deployment used?

Public Cloud

Suppose you want to deploy an application to the internet, focusing only on application development and leaving infrastructure to others. What type of cloud service is the best?

PaaS

Deploying a Cloud Instance

What is the total cost of credits of the entire environment if study-machine-1 and study-machine-2 are stopped?

30

How many credits does an m5.large EC2 instance cost per month?

70

What is the total cost of credits if only the new instances we created are running?

150

What would be the total running cost of the entire environment you created if you add a third t3a.small study machine?

188

Conclusion

Public Cloud → cloud bersama yang diakses lewat internet.
Private Cloud → cloud khusus satu organisasi, kontrol lebih besar.
Hybrid Cloud → gabungan public dan private cloud.
IaaS → sewa server, storage, dan networking.
PaaS → lingkungan siap pakai untuk membangun dan menjalankan aplikasi.
SaaS → aplikasi siap pakai melalui internet, seperti Gmail atau Zoom.
EC2 → layanan virtual computer dari AWS yang bisa dibuat dan diubah kapasitasnya sesuai kebutuhan.

Computer Fundamentals

Inside a Computer System