computer science

H2O (web server)

H2O (web server) is a computer science topic covered in the lgStudy science library. This page brings together a partial reference excerpt, illustrations, worked examples, real-world applications and a short study plan, so you can understand H2O (web server) rather than just read about it. In short: H2O is a free and open-source web server. It is written in C, and is distributed under the terms of the MIT License.

Key takeaways

H2O (web server) belongs to computer science; place it in that map before memorising details.
Learn the definition first, then one example that makes the definition concrete.
Connect H2O (web server) to a quantity you can measure, compute or draw — that is where exam questions come from.
Reproduce the core statement of H2O (web server) from memory before moving on to harder problems.

Reference excerpt

H2O is a free and open-source web server. It is written in C, and is distributed under the terms of the MIT License. It was designed with a focus on supporting HTTP/2 and TLS, maximizing the use of new web technologies such as prioritization and server push. As a result it achieves significantly better performance than conventional web servers such as nginx.

Features H2O has the following key features:

HTTP/1.0 and HTTP/1.1 support HTTP/2 support Full support for dependency and weight-based prioritization with server-side tweaks Cache-aware server push HTTP/3 support (experimental) TCP Fast Open TLS support Session resumption (standalone and memcached) Session tickets with automatic key rollover Automatic OCSP stapling Forward secrecy and fast AEAD cipher suite Private key protection using privilege separation Encrypted Client Hello (experimental) Static file serving FastCGI support Reverse proxy Scripting using mruby (Rack-based) Graceful restart and self-upgrade

History In July 2014, Kazuho Oku started development of H2O for usage as a server for mobile games while working at DeNA. The initial version was released in December 2014, and the first stable version was released in February 2015 when the HTTP/2 specification was finalized.

Worked examples

Example 1 — a first encounter with H2O (web server)

Start with the simplest possible case. Write down what H2O (web server) claims or describes in one sentence, then invent the smallest concrete situation in which that sentence is true. In computer science, the smallest case is usually a single object, a single equation or a single measurement. Check that every symbol or term in your sentence has a meaning in that case.

Example 2 — changing one variable

Take the situation from Example 1 and change exactly one quantity: double it, halve it, or set it to zero. Predict what should happen to H2O (web server) before you calculate. Comparing your prediction with the result is the fastest way to find out whether you understand the idea or only the words.

Example 3 — an exam-style question

Typical questions about H2O (web server) ask you to (a) state it precisely, (b) apply it to given data, and (c) explain a limitation. Practise writing all three answers in under five minutes; the third part is what separates a full-mark answer from an average one.

Applications of H2O (web server)

In research: H2O (web server) appears in computer science research whenever the underlying quantities have to be modelled precisely. Papers usually cite it as a starting assumption and then explore where it breaks down.
In technology and industry: Engineering practice reuses H2O (web server) in design rules, simulations and safety margins. Knowing the idea lets you read a specification sheet and understand why the numbers look the way they do.
In the classroom: H2O (web server) is common in secondary-school and first-year university syllabi. It links to neighbouring topics 2015 software, DeNA, Free and open-source software stubs, so understanding it makes those chapters shorter.
In everyday life: Look for H2O (web server) outside the textbook — in sport, cooking, traffic, electronics or the sky above you. An example you found yourself is remembered far longer than one you were given.

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How to study H2O (web server) in 20 minutes

Read the reference excerpt below once, without taking notes.
Close the page and write down what H2O (web server) means in your own words.
Compare your version with the excerpt and mark what you missed.
Work through the three examples above with pen and paper.
Explain H2O (web server) out loud to somebody else — or to Teacher Smith in the lgStudy chat.

Frequently asked questions

What is H2O (web server) in simple terms?

H2O is a free and open-source web server. It is written in C, and is distributed under the terms of the MIT License.

Why does H2O (web server) matter?

Because it connects several computer science ideas at once: it gives you a definition you can apply, a quantity you can calculate, and a way to check whether a result is plausible.

How should I study H2O (web server)?

Read the excerpt, restate it from memory, then work through the examples and applications listed on this page. The five-step study plan above takes about twenty minutes.

What does this page cover?

It gives you a compact reference excerpt plus original lgStudy explanations, examples, applications and study material on H2O (web server).