computer science

PuTTY

PuTTY 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 PuTTY rather than just read about it. In short: PuTTY () is a free and open-source terminal emulator, serial console and network file transfer application. It supports several network protocols, including SCP, SSH, Telnet, rlogin, and raw socket connection.

Key takeaways

PuTTY 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 PuTTY to a quantity you can measure, compute or draw — that is where exam questions come from.
Reproduce the core statement of PuTTY from memory before moving on to harder problems.

Reference excerpt

PuTTY () is a free and open-source terminal emulator, serial console and network file transfer application. It supports several network protocols, including SCP, SSH, Telnet, rlogin, and raw socket connection. It can also connect to a serial port. The name "PuTTY" has no official meaning. PuTTY was originally written for Microsoft Windows, but it has been ported to various other operating systems. Official ports are available for some Unix-like platforms, with work-in-progress ports to Classic Mac OS and macOS, and unofficial ports have been contributed to platforms such as Symbian, Windows Mobile and Windows Phone. PuTTY was written and is maintained primarily by Simon Tatham, a British programmer.

Features PuTTY supports many variations on the secure remote terminal, and provides user control over the SSH encryption key and protocol version, alternate ciphers such as AES, 3DES, RC4, Blowfish, DES, and public-key authentication. PuTTY uses its own format of key files – PPK (protected by Message Authentication Code). PuTTY supports SSO through GSSAPI, including user provided GSSAPI DLLs. It also can emulate control sequences from xterm, VT220, VT102 or ECMA-48 terminal emulation, and allows local, remote, or dynamic port forwarding with SSH (including X11 forwarding). The network communication layer supports IPv6, and the SSH protocol supports the zlib@openssh.com delayed compression scheme. It can also be used with local serial port connections. PuTTY comes bundled with command-line SCP and SFTP clients, called "pscp" and "psftp" respectively, and plink, a command-line connection tool, used for non-interactive sessions. PuTTY does not support session tabs directly, but many wrappers are available that do.

History PuTTY development began in 1996, and was a usable SSH-2 client by October 2000.

Components PuTTY consists of several components:

PuTTY the Telnet, rlogin, and SSH client itself, which can also connect to a serial port PSCP an SCP client, i.e. command-line secure file copy. Can also use SFTP to perform transfers PSFTP an SFTP client, i.e. general file transfer sessions much like FTP PuTTYtel a Telnet-only client Plink a command-line interface to the PuTTY back ends. Usually used for SSH Tunneling Pageant an SSH authentication agent for PuTTY, PSCP and Plink PuTTYgen an RSA, DSA, ECDSA and EdDSA key generation utility pterm (Unix version only) an X11 client which supports the same terminal emulation as PuTTY

Illustrations

Worked examples

Example 1 — a first encounter with PuTTY

Start with the simplest possible case. Write down what PuTTY 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 PuTTY 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 PuTTY 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 PuTTY

In research: PuTTY 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 PuTTY 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: PuTTY is common in secondary-school and first-year university syllabi. It links to neighbouring topics 1998 software, Cross-platform free software, Cryptographic software, so understanding it makes those chapters shorter.
In everyday life: Look for PuTTY 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 PuTTY in 20 minutes

Read the reference excerpt below once, without taking notes.
Close the page and write down what PuTTY 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 PuTTY out loud to somebody else — or to Teacher Smith in the lgStudy chat.

Frequently asked questions

What is PuTTY in simple terms?

Why does PuTTY 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 PuTTY?

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 PuTTY.