HackerNews Summary (2023-05-22 07AM)

Source: Black holes might be defects in spacetime

Summary
A team of theoretical physicists have uncovered an exotic structure of spacetime that appears to a distant observer as a black hole, but on closer inspection is anything but. These topological solitons are natural defects in space-time, as stable as cracks in ice, and are being used as test studies to find an observation that is distinct from a traditional black hole, potentially leading to viable updates to our understanding of physics and theories like string theory.

Facts

🌌 Topological solitons are stable defects in space-time that appear as black holes to distant observers.

🪐 They require no matter or other forces to exist and are as natural to the fabric of space-time as cracks in ice.

🌠 Topological solitons are based on our understanding of string theory, which aims to explain all particles in the universe as microscopic vibrating loops of string.

🔍 By discovering a specific observation difference between topological solitons and traditional black holes, researchers may be able to test string theory and find better explanations to demonstrate our understanding of physics.

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Source: Vim Ninja — Master Vim From Your Browser Through Interactive Exercises

Summary
Learn Vim on your web browser with no setup time and practice on any device.

Fact

🖥️ No setup required on local machine

🌐 Learn Vim on web browser

💻 Practice Vim on any device

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Source: dankwiki, the wiki of nick black

Summary
io_uring is a system for providing the kernel with a schedule of system calls and receiving the results, combining asynchronous I/O, system call polybatching, and flexible buffer management. It uses SQEs (Submission Queue Entries) and CQEs (Completion Queue Entries) descriptors on two shared ringbuffers, and does not generally make use of errno.

Facts

🔄 io_uring allows specifying the system calls themselves and executing the schedule at the kernel “dataflow limit”.

📡 It supports both polling- and interrupt-driven I/O on the kernel side.

🔒 io_uring does not generally make use of errno, and completion queue entries have the negated error code placed in their res fields.

💾 SQEs roughly correspond to a single system call, are allocated externally to the submission queue, and are tagged with an operation type.

📈 CQEs are usually 16 bytes, and SQEs are usually 64 bytes (but see IORING_SETUP_SQE128 and IORING_SETUP_CQE32 below).

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Source: The Culture: The Drawings

Summary
Sign up for the Little, Brown newsletter to stay updated on upcoming publications, competitions, and author updates. You must be 13 or over to sign up, and you can unsubscribe at any time.

Fact

✉️ Receive news on upcoming publications and author updates

🎉 Enter competitions by signing up

🔐 Your data is protected according to our Privacy Notice

📋 We may send you surveys to get to know you better

👋 You can unsubscribe at any time

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Source: Rail passengers in England could lose wifi access amid cost cuts

Summary
The UK government has told train companies to stop offering wifi services unless it can be shown they are profitable. The officials say that trains need to reduce costs and they are looking to reform the railways.

Fact

📉  The Department of Transport is determined to cut costs and has informed the contracted train operators to cease the wifi service if they cannot justify the cost.

🚆  The officials are keen to reform the railway and make it financially stable. The department claims that wifi is low on passengers’ priorities, especially on shorter journeys.

🔁  Passenger groups and transport industry experts had criticized the decision, citing the need to attract passengers back to the railways in light of fewer peak commuters due to the pandemic.

📱  Transport Focus’s survey showed that wifi on trains wasn’t a top priority when measured against essential features like value-for-money fares, punctuality, personal security, and reliability.

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