About OS Flashcards
Introduction - Chapter 0
What is the difference between a Monolithic and a Microkernel OS?
Monolithic: All systems and services on the OS are run with a single program in kernel mode.
Microkernel: Only essential services operate on the main kernel, otherwise different processes use different address spaces.
Name a prominent monolithic operating system from the following: Linux, Windows, Mac.
Linux or Windows. Mac is on a hybrid structure.
Name a prominent microkernel operating system from the following: Linux, Windows, Mac.
None of the given. Mac is on a hybrid structure, and the other two are monolithic.
What is a CPU?
The computer’s “brain;” Controls other parts of the device. Stands for “Central Processing Unit.”
What is memory built to do in computers?
Support processing through storage of instructions and data. Includes caching.
What are L1, L2, and L3?
Three different levels of cache memory. L1 is the fastest but smallest, L3 is the slowest (faster than disc access though) and biggest.
What is DRAM?
Dynamic Random Access Memory. Computer memory that stores data temporarily for CPU usage during applications. The main computer memory above disc space.
What’s the difference between the group of L1, L2, and L3 and DRAM?
DRAM is main memory unit, while L1-3 are smaller caches.
What is the Frontside bus?
Connects the CPU to main memory and speedy components.
What is the Backside bus?
Connects the CPU to the L2 and L3 caches.
Where is the L1 cache stored?
In the CPU itself; Runs at the same speed as the CPU.
What is the system bus?
Connects the CPU to all system components.
What is a HDD?
Hard Drive Disc. Physical Memory stored on a mechanical rotating disc. Good at sequential memory access.
What is an SSD?
Solid-State Drive. Non-mechanical. Great at random access.
What’s the main advantage of HDD’s over SSD’s?
Price.
What is an NIC?
Network Interface Card. Interfaces with networks. Can interface with ethernet cables or wireless methods.
What is a GPU?
Graphics Processing Unit. Handles display of image on a computer. Good at parallel processing.
What is a TPU?
Hardware accelerator designed to optimize machine learning tasks (especially deep learning models).
What is an FPGA?
Field-Programmable Gate Array. Type of semiconductor that can be programmed to handle specific functionality even after manufacturing. Pricey, but efficient.
What does Moore’s Law outline?
Transistor capacity doubles every ~18 months, though this has hit a wall in 2003, instead people now focus on multi-core systems.
When does a Bootstrapping Process start?
When power is initially applied.
What does the OS Bootstrapping Process aim to accomplish?
Get the system ready to service user actions and needs.
TRUE/FALSE: The bootstrapping process will only ever provide services to a user after the booting is completed.
FALSE: Services might be provided before booting completion (GUI display). Example: Connecting to the network for SSH use, or displaying a Splash screen before user can run programs.
What are the three basic operating system duties?
Resource Management, Isolation & Security, and Scheduling.
Describe an Operating System’s handling of Resource Management.
The initialization of physical resources, sharing and managing resources for the kernel and applications, abstraction of resources, and managing power and sleep status.
Describe an Operating System’s handling of Isolation & Security.
Managing disjoint users and processes at the same time, making sure little degradation of other processes occurs when a large process happens at the same time (guarding against noisy neighbors), and securing data.
Describe an Operating System’s handling of Scheduling.
Allowing many processes to share a set of cores, enabling the switch between processes (threading) with minimal latency, determining which process is run after one stops.
TRUE/FALSE: Hard Realtime Systems are designed to optimize worst-case performance.
TRUE.
TRUE/FALSE: Firm Realtime Systems care primarily about the amount of time a deadline is missed by.
FALSE: Firm Realtime Systems care primarily about the number and percentage of missed deadlines.
TRUE/FALSE: An example of a Soft Realtime System is a router.
TRUE.
