Introduction to Computing Platforms & OS Fundamentals Flashcards

Vocabulary flashcards covering computing platform architecture, kernel modes, OS roles, kernel types, operating system comparisons, and virtualization hypervisors.

Computing Platform

The foundational combination of hardware architecture and operating system environment that provides the execution framework for software applications.

Operating System (OS)

Core system software that manages physical hardware resources (processor time, main memory, peripheral storage, input/output operations) and provides standard execution services for user applications.

Kernel

The foundational core component of an operating system that operates at the highest execution privilege level, maintaining total control over hardware resources, memory space, and process execution.

Instruction Set Architecture (ISA)

The standardized interface between computer hardware and software that defines the machine-level commands, CPU registers, address modes, and data types supported by a processor (e.g., x86_64, ARM64).

Kernel Space (Kernel Mode / Ring 0)

A protected, highly privileged processor execution mode where the OS kernel resides, allowing direct, unrestricted execution of CPU instructions and direct hardware access.

User Space (User Mode / Ring 3)

An isolated, restricted processor execution mode where user applications, utilities, and background applications run, preventing software bugs or rogue code from damaging system hardware or kernel memory.

System Call (Syscall)

The standardized software interface that allows a user-space application to safely request privileged services—such as reading a file from disk, allocating additional memory, or establishing a network connection—from the OS kernel.

Hardware Abstraction Layer (HAL)

A low-level code module within an OS that hides hardware vendor differences behind standardized interfaces, enabling the kernel to interact with diverse hardware components without requiring custom kernel rewrites.

Hypervisor (Virtual Machine Monitor - VMM)

Software, firmware, or hardware that abstracts physical host resources to create, run, and isolate multiple virtualized computing environments simultaneously.

Host Operating System

The primary operating system installed directly on the physical machine's bare-metal hardware that runs hardware drivers and hypervisors like Oracle VirtualBox.

Guest Operating System

An operating system running inside an isolated Virtual Machine (VM), interacting with virtualized hardware presented by the underlying hypervisor.

Virtual Machine (VM)

A tightly isolated, software-emulated container that behaves like an independent physical computer with its own virtualized CPU, RAM, disk, and network interfaces.

Monolithic Kernel

An OS kernel design where all major OS services (process scheduling, memory management, file systems, device drivers, network stacks) run together inside a single, highly privileged address space in Kernel Mode.

Microkernel

An OS kernel design that keeps only the absolute bare minimum in Kernel Mode (basic IPC, low-level memory management, and primitive thread scheduling), running services like file systems and drivers as user-space daemons.

Hybrid Kernel

An OS kernel design that combines the modular layout of a microkernel with the high-performance execution of a monolithic kernel by running critical subsystems in kernel space while maintaining structured sub-service interfaces.

Type-1 Hypervisor (Bare-Metal)

A hypervisor that installs directly on physical host hardware without an underlying host OS, providing low overhead, high virtualization performance, and enterprise-grade scalability.

Type-2 Hypervisor (Hosted)

A hypervisor that installs as a software application on top of an existing host operating system and uses the host OS drivers to manage physical hardware calls.

Hypervisor Architecture Comparison

The structural comparison between Type-1 bare-metal VMMs operating directly on physical hardware and Type-2 hosted hypervisors operating on top of a host OS.

Windows Architecture

A proprietary, closed-source operating system architecture built on the Windows NT Hybrid Kernel, natively supporting Active Directory, centralized group policies, and NTFS/ReFS file systems.

Linux Architecture

An open-source, monolithic kernel operating system ecosystem featuring ext4/Btrfs/XFS file systems and CLI management (Bash/Zsh), widely used for cloud infrastructure, web servers, and containerization.