Concurrency control

Giant lock

In operating systems, a giant lock, also known as a big-lock or kernel-lock, is a lock that may be used in the kernel to provide concurrency control required by symmetric multiprocessing (SMP) systems. A giant lock is a solitary global lock that is held whenever a thread enters kernel space and released when the thread returns to user space; a system call is the archetypal example. In this model, threads in user space can run concurrently on any available processors or processor cores, but no more than one thread can run in kernel space; any other threads that try to enter kernel space are forced to wait. In other words, the giant lock eliminates all concurrency in kernel space. By isolating the kernel from concurrency, many parts of the kernel no longer need to be modified to support SMP. However, as in giant-lock SMP systems only one processor can run the kernel code at a time, performance for applications spending significant amounts of time in the kernel is not much improved. Accordingly, the giant-lock approach is commonly seen as a preliminary means of bringing SMP support to an operating system, yielding benefits only in user space. Most modern operating systems use a fine-grained locking approach. (Wikipedia).

Video thumbnail

Solving The Most DIFFICULT Lock Puzzle on the Planet!! - LEVEL 10

Today I'm going to attempt to solve the most difficult lock puzzle in the world, the rare, Level 10 Crown Iron Lock Puzzle! This is a handmade metal lock puzzle which weighs around 5 lbs, consisting of several internal maze puzzles and a key which should unlock it! Enjoy! BUY PUZZLES HERE

From playlist Puzzles!

Video thumbnail

Samsung Galaxy S5 customization - set up lock screen

In this video we teach you how to set up the Samsung Galaxy S5 lock screen to provide some security for your phone.

From playlist Technology

Video thumbnail

This LOCK is NOT What it Seems!! - Solving the CHALLENGING Lock Puzzle!

B Lock Puzzle: http://bit.ly/2Fx8urh Today I'm attempting to solve the infamous B Lock puzzle by Boaz Feldman. This lock puzzle is very difficult and can be used as an actual lock! The secret to opening is contained within the lock and key. Enjoy! OTHER LOCK PUZZLE VIDEO: https://www.you

From playlist Puzzles!

Video thumbnail

Solving The ANCIENT Lock Puzzle!!

Today, I'm attempting to solve this ancient Lock Puzzle replica. Made of steel, this level 7 puzzle weighs 1.5KG and comes with a set of three keys which will help me to unlock it. Enjoy! BUY PUZZLES LIKE THIS HERE: http://www.puzzlemaster.ca/?a=681162 INSTAGRAM: https://www.instagram.co

From playlist Puzzles!

Video thumbnail

Combination Locks - Intro to Algorithms

This video is part of an online course, Intro to Algorithms. Check out the course here: https://www.udacity.com/course/cs215.

From playlist Introduction to Algorithms

Video thumbnail

How to change door locks

Demonstrated using the Yale Knob Lockset.

From playlist Everyday How-to

Video thumbnail

Tsar bomba

The Tsar Bomba footage 50Mt. The largest nuclear detonation in history.

From playlist Best of Science!

Video thumbnail

The Largest Land-Based Crane in the World: Massive SGC-250

The massive SGC-250 crane, the biggest and most potent crane in Sarens' fleet in terms of size and capability, was presented.  They are doing a load-in, loading, and assembly of jackets for the bleacher project in this new episode of Giant Machines. Additionally, they are making a stateme

From playlist Giant Machines

Video thumbnail

Solving The ANCIENT KEY LOCK Puzzle!!

Today I'm going to attempt to solve the Ancient Key Lock Puzzle by Jean-Claude Constantin. The objective is to open the key-shaped lock with the help of the small key that is attached. The only problem is where do you put it in order to open the lock? Enjoy! 1000's of PUZZLES Available h

From playlist Puzzles!

Video thumbnail

When Will Earth Lock to the Moon? Becoming a Binary Planet

The Moon is tidally locked to the Earth so it always shows us the same face. But the Earth is slowing down so that it’ll eventually lock to the Moon as well. What are the forces involved and when will this happen? Support us at: http://www.patreon.com/universetoday More stories at: http:/

From playlist Guide to Space

Video thumbnail

Could planets from Star Trek TNG really exist?

Space. The final frontier. Full of Californian planets. Watch Dr Wakeford and I discuss the physics of Kraofewd on Nebula (link updated March 2023): https://nebula.tv/videos/simon-clark-free-as-a-bird-original-episode-with-discussion In this video Dr Hannah and I go through every planet f

From playlist Science videos

Video thumbnail

IMAGINE: What if Earth Orbited Saturn?

You can buy Universe Sandbox 2 game here: http://amzn.to/2yJqwU6 Hello and welcome to What Da Math! In this video, we will talk about Earth in orbit of Saturn Support this channel on Patreon to help me make this a full time job: https://www.patreon.com/whatdamath Space Engine is availa

From playlist Space Engine

Video thumbnail

Giant Neodymium Monster Magnet vs Superconductor—Quantum Locking Part 2

In this video I show you what happens when you expose a type 2 superconductor to a very strong magnetic field from a giant neodymium magnet. In a previous video I explain more about quantum locking or flux pinning. See this video here: Quantum Locking Will Blow Your Mind—How Does it Work?

From playlist The Action Lab Does Quantum Mechanics

Video thumbnail

Top 5 GREATEST Mysteries of Great Britain | The Proof Is Out There

Check out these 5 insane UK mysteries in this compilation from The Proof Is Out There. 00:00- Loch Ness 04:17- Giant Bird Murmuration 09:13- Anti-gravity Hillside 12:57- Gravity Defying Waterfall 17:01- Nessie’s Cousin Watch all your favorite episodes of The Proof Is Out There, and st

From playlist The Proof Is Out There: Official Series Playlist | History

Video thumbnail

The Truth Behind The Panama Canal | Super Structures | Spark

Deep in the jungles of Central America, man has battled nature to build an engineering marvel. Its epic story continues to astonish us! Its dimensions defy imagination! It’s price…thousands of lives. It’s the crossroads of the world’s economy. Many have gone to war over it. Subscribe to S

From playlist Super Structures

Video thumbnail

What if Jupiter Orbited Closer to the Sun?

Hello and welcome to What Da Math! Check out the website mentioned at https://brilliant.org/AntonPetrov/ 20% off subscription for first 200 sign ups of Brilliant Premium subscription You can buy Universe Sandbox 2 game here: http://amzn.to/2yJqwU6 Support this channel on Patreon to help

From playlist Jupiter and Its Moons

Video thumbnail

5 MYSTERIOUS SEA MONSTERS UNCOVERED | The Proof is Out There

These five sea creatures are some of the most unusual beasts ever seen, in this The Proof Is Out There compilation. 0:00 - Water Demon Ogopogo 5:11 - Massive Globster 9:27 - Mysterious Alaskan Serpent 13:07 - Gulf Of Mexico Prehistoric Sea Monster 17:06 - Irish Sea Eel If you are intere

From playlist The Proof Is Out There: Official Series Playlist | History

Video thumbnail

[Twitch] Universe Sandbox 2 - Part 1 - Terraforming

Hello and welcome to What Da Math. [this video is edited for your convenience, non edited video erased] In this video we are going to try to terraform and also create various things on Twitch using Universe Sandbox 2. This was recorded on Twitch here: http://www.twitch.tv/whatdamath Th

From playlist Universe Sandbox 2

Video thumbnail

Are TRAPPIST-1 Planets Really Tidally Locked?

Hello and welcome to What Da Math! In this video, we will talk about why we know for a fact TRAPPIST-1 planets are tidally locked to their parent stars. Patreon page: https://www.patreon.com/user?u=2318196&ty=h Enjoy and please subscribe. Other videos here: https://www.youtube.com/playl

From playlist Universe Sandbox 2

Video thumbnail

Make A Combination Lock - Intro to Algorithms

This video is part of an online course, Intro to Algorithms. Check out the course here: https://www.udacity.com/course/cs215.

From playlist Introduction to Algorithms

Related pages

Lock (computer science) | Global interpreter lock | Concurrency control