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PSINet

PSINet is a 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 PSINet rather than just read about it. In short: PSINet, formerly Performance Systems International, was an American internet service provider based in Ashburn, Virginia. As one of the first commercial Internet service providers (ISPs), it was involved in the commercialization of the Internet until the company's bankruptcy in 2001 during the dot-com bubble and subsequent acquisition by Cogent Communications in 2002.

PSINet — main illustration
PSINet — illustration

Key takeaways

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

Reference excerpt

PSINet, formerly Performance Systems International, was an American internet service provider based in Ashburn, Virginia. As one of the first commercial Internet service providers (ISPs), it was involved in the commercialization of the Internet until the company's bankruptcy in 2001 during the dot-com bubble and subsequent acquisition by Cogent Communications in 2002. It was founded on December 5, 1989, and began offering services, including limited for-profit access to the Internet, on January 1, 1990, becoming one of the first companies to sell Internet connectivity.

History

Founding PSINet was founded in 1989 by Martin L. Schoffstall and William L. Schrader, who initially funded the company through personal loans, including using credit cards and by selling the family car. It was initially known as Performance Systems International. In very late 1989, the company acquired NYSERNet assets and established an ongoing outsourcing contract with NYSERNet. NYSERNet, a non-profit research and education network serving New York State, had created one of the first regional Internet networks under Schrader's and Richard Mandelbaum's leadership and technical leadership from Schoffstall, Mark Fedor, and others. This acquisition gave PSINet commercial access to what would come to be known as the Internet.

Commercialization Before 1990, the Internet had been largely funded by government agencies including DARPA (the original and still existing at that time, ARPANET), the National Science Foundation (NSF) for NSFNET, various U.S. federal agency networks such as the Department of Energy and NASA, and with grants to various regional networks including NYSERNet. Many of the stake-holders of the Internet of the 1980s were military, industrial, or academic researchers who were largely satisfied with the then current model of usage and governance. However, appropriate commercial usage policies were debated on such mailing lists as com-priv (commercialization and privatization of the Internet), within semi-public forums such as the Internet Engineering Task Force (IETF), and included an investigation by the NSF's Inspector General staff. This included an intense debate on the "settlement model" of the Internet which was worldwide and both public and private in scope. The NSF's appropriations act authorized NSF to "foster and support the development and use of computer and other scientific and engineering methods and technologies, primarily for research and education in the sciences and engineering." This allowed NSF to support NSFNET and related networking initiatives, but only to the extent that that support was "primarily for research and education in the sciences and engineering." And this in turn was taken to mean that use of NSFNET for commercial purposes was not allowed. At the time the National Science Foundation (NSF) believed in a settlement model based on usage, with payments or contributions based on how much data was sent or received, mirroring the public X.25 networks at that time. Such a settlement policy would allow research and education and commercial traffic to share a common network infrastructure without using NSF funds to support the commercial use. NSF in fact entered into an agreement with the non-profit Advanced Network and Services to allow commercial traffic through a for-profit subsidiary, ANS CO+RE (commercial plus research), subject to the conditions (i) that the NSFNET Backbone Service was not diminished; (ii) that ANS CO+RE recovered at least the average cost of the commercial traffic traversing the network; and (iii) that any excess revenues recovered above the cost of carrying the commercial traffic would be placed into an infrastructure pool to be distributed by an allocation committee broadly representative of the networking community to enhance and extend national and regional networking infrastructure and support. PSINet through Schrader, Schoffstall, Rick Adams of UUNET, Mitch Kapor, and others waged an intense policy battle that the Internet needed a fixed access payment strategy to ensure that the ultimate utility of the Internet become available to all.

Initial public offering PSINet eventually took venture capital investment from Matrix Partners, Sigma Partners, and Amerindo as a private entity to grow the company throughout the US and then outside of the country. On May 1, 1995, the initial public offering listed its shares on the NASDAQ stock exchange under symbol PSIX.

… excerpt ends here. Continue reading the full article.

Illustrations

PSINet illustration

Worked examples

Example 1 — a first encounter with PSINet

Start with the simplest possible case. Write down what PSINet claims or describes in one sentence, then invent the smallest concrete situation in which that sentence is true. In 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 PSINet 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 PSINet 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 PSINet

In research
PSINet appears in 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 PSINet 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
PSINet is common in secondary-school and first-year university syllabi. It links to neighbouring topics Defunct Internet service providers, History of the Internet, Internet service providers of the United States, so understanding it makes those chapters shorter.
In everyday life
Look for PSINet 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 PSINet in 20 minutes

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

Frequently asked questions

What is PSINet in simple terms?

PSINet, formerly Performance Systems International, was an American internet service provider based in Ashburn, Virginia. As one of the first commercial Internet service providers (ISPs), it was involved in the commercialization of the Internet until the company's bankruptcy in 2001 during the dot…

Why does PSINet matter?

Because it connects several 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 PSINet?

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 PSINet.

Tags

  • Defunct Internet service providers
  • History of the Internet
  • Internet service providers of the United States
  • Technology companies disestablished in 2001
  • Telecommunications companies established in 1989

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