computer science

3Com

3Com 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 3Com rather than just read about it. In short: 3Com Corporation was an American digital electronics manufacturer best known for its computer network products. The company was co-founded in 1979 by Robert Metcalfe, Howard Charney and others.

Key takeaways

3Com 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 3Com to a quantity you can measure, compute or draw — that is where exam questions come from.
Reproduce the core statement of 3Com from memory before moving on to harder problems.

Reference excerpt

3Com Corporation was an American digital electronics manufacturer best known for its computer network products. The company was co-founded in 1979 by Robert Metcalfe, Howard Charney and others. Bill Krause joined as President in 1981. Metcalfe explained the name 3Com was a contraction of "Computer Communication Compatibility", with its focus on Ethernet technology that he had co-invented, which enabled the networking of computers. 3Com provided network interface controller and switches, routers, wireless access points and controllers, IP voice systems, and intrusion prevention systems. The company was based in Santa Clara, California. From its 2007 acquisition of 100 percent ownership of H3C Technologies Co., Limited (H3C) —initially a joint venture with China-based Huawei Technologies—3Com achieved a market presence in China, and also sold products in Europe, Asia, and the Americas. 3Com products were sold under the brands 3Com, H3C, and TippingPoint. On April 12, 2010, Hewlett-Packard completed the acquisition of 3Com. It was merged into HPE's Aruba Networks business unit following HP's acquisition of Aruba in 2015 and subsequent split into HPE later that same year.

History

Xerox PARC (1972–1979) After reading an article on ALOHAnet, Robert Metcalfe became interested in computer networking. ALOHAnet was an over-the-air wide area network system in Hawaii using ultra high frequency radios and made several assumptions that Metcalfe thought would not be correct in practice. He developed his own theories of how to manage traffic, and began to consider an "ALOHAnet in a wire" networking system. In 1972, he joined Xerox PARC to develop these ideas, and after pairing up with David Boggs, the two had early 3 Mbit/s versions of Ethernet working in 1973. They then went on to build up a networking protocol known as PARC Universal Packet (PuP), with the entire system ready for build-out by late 1974. At this point, Xerox management did nothing with it, even after being approached by prospective customers. Increasingly upset by management's lack of interest, Metcalfe left Xerox in 1975, but he was lured back again the next year. Further development followed, resulting in the seminal Xerox Network Systems (XNS) protocol, which was completed by 1978. Once again, Metcalfe found that management was unwilling to actually do anything with the product, and he threatened to leave and in 1979 he left the company.

Founding and early days (1979–1996) Metcalfe subsequently co-founded 3Com in 1979. The other co-founders were Metcalfe's college friend Howard Charney and two others. Bill Krause joined as President in 1981 and became CEO in 1982 and led 3Com until 1992 when he retired. 3Com began making Ethernet adapter cards for many early 1980s computer systems, including the DEC LSI-11, DEC VAX-11, Sun-2 and the IBM PC. In the mid-1980s, 3Com branded their Ethernet technology as EtherSeries, while introducing a range of software and PC-based equipment to provide shared services over a local area network (LAN) using XNS protocols. These protocols were branded EtherShare (for file sharing), EtherPrint (for printing), EtherMail (for email), and Ether-3270 (for IBM host emulation). 3Com became a public company via an initial public offering (IPO) in 1984. The company's network software products included:

3+Share file and printer sharing. 3+Mail e-mail. 3+Route for routing XNS over a 3+ Server serial port towards a remote 3+ (Route) LAN. 3+Remote/PC for routing XNS towards a Remote 3+ PC Workstation serial port. 3+NetConnect to support flexible XNS routing between a number of connected 3+ Ethernets AND/OR Token Ring Networks. 3+3270/SNA Gateway to enable standard 3+ MS-DOS workstations to emulate standard IBM 3270 Terminals, via the 3+ LAN and the connected SNA Gateway, towards a remote IBM-compatible mainframe system MultiConnect (?) was a chassis-based multi-port 10BASE2 Ethernet repeater. 3Server, a server-grade PC for running 3+ services. 3Station, a diskless workstation. 3+Open file and printer sharing (based on Microsoft's LAN Manager). Etherterm terminal emulation. Etherprobe LAN analysis software. DynamicAccess software products for Ethernet load balancing, response time, and RMON II distributed monitoring.

3Com's expansion beyond its original base of PC and thin Ethernet products began in 1987 when it merged with Bridge Communications. This provided a range of equipment based on Motorola 68000 processors and using XNS protocols compatibly with 3Com's Etherterm PC software.

CS/1, CS/200 communication servers ("terminal servers") Ethernet bridges and XNS routers GS/1-X.25 X.25 gateway CS/1-SNA SNA gateway NCS/1 network control software running on a Sun Microsystems computer By 1995, 3Com's status was such that it was able to enter into an agreement with the city of San Francisco to pay $900,000 per year for the naming rights to Candlestick Park. That agreement ended in 2002.

1997–2000

… excerpt ends here. Continue reading the full article.

Illustrations

Worked examples

Example 1 — a first encounter with 3Com

Start with the simplest possible case. Write down what 3Com 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 3Com 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 3Com 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 3Com

In research: 3Com 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 3Com 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: 3Com is common in secondary-school and first-year university syllabi. It links to neighbouring topics 1979 establishments in California, 1980s initial public offerings, 2010 disestablishments in California, so understanding it makes those chapters shorter.
In everyday life: Look for 3Com 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.

Ask Teacher Smith questions about this articleOpens your AI tutor with a question about “3Com” →

Affiliate

Preply — study more efficiently by working with a personal tutor. 50% off.

How to study 3Com in 20 minutes

Read the reference excerpt below once, without taking notes.
Close the page and write down what 3Com 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 3Com out loud to somebody else — or to Teacher Smith in the lgStudy chat.

Frequently asked questions

What is 3Com in simple terms?

3Com Corporation was an American digital electronics manufacturer best known for its computer network products. The company was co-founded in 1979 by Robert Metcalfe, Howard Charney and others.

Why does 3Com 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 3Com?

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 3Com.