computer science

Ted Kaehler

Ted Kaehler 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 Ted Kaehler rather than just read about it. In short: Ted Kaehler (born 1950) is an American computer scientist known for his role in the development of several system methods. He is most noted for his contributions to the programming languages Smalltalk, Squeak, and Apple Computer's HyperCard system, and other technologies developed at Xerox PARC.

Key takeaways

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

Reference excerpt

Ted Kaehler (born 1950) is an American computer scientist known for his role in the development of several system methods. He is most noted for his contributions to the programming languages Smalltalk, Squeak, and Apple Computer's HyperCard system, and other technologies developed at Xerox PARC.

Background Kaehler is a son of a mechanical engineer and grew up tinkering with mechanical toys. During the 1960s, he built a computer on his own following an article published in Scientific American. He went to Gunn High School, a public school in Palo Alto, California. He graduated in 1968. While in high school, Kaehler was accepted to a summer job at then named Fairchild Industries. During this work, he learned the programming language Fortran. During his high school days, he was introduced to his first computer, an IBM 1620, operated by the Palo Alto Unified School District. Kaehler then attended Stanford University to study physics, studied programming under Donald Knuth, learned the language APL, and met Dan Ingalls. He graduated with a Bachelor of Science (B.S.) in physics in 1972. Later, Xerox began a pilot program with Gunn High School, loaning them a Xerox Alto.

Xerox PARC Ingalls introduced Kaehler to PARC when he secured a contract with Xerox. They formed a team that included George White, who was already with the company working on speech recognition software. During his early years at PARC, he attended Carnegie Mellon University. He graduated with a Master of Science (MSc) in computer science in 1976. By the 1980s, he was reportedly demonstrating a virtual reality (VR) technology that involved a user in Maze War 3D game. This depiction successfully voiced a response in-world to another user in the real world. The development has been touted as the first avatar-centric reference to this kind of VR technology. Kaehler was also documented as one of the researchers at PARC who briefed Steve Jobs about the company's three innovations: the graphical user interface (GUI) of the Xerox Alto computer, Smalltalk, and Ethernet network at PARC.

Smalltalk Kaehler was part of a group led by Dr. Alan Kay who refined the concept of network computing through Smalltalk. This is a system that drew from John McCarthy's language LISP and from simulation programming language Simula, versions 1 and 67, which were developed by the Norwegian Computing Center. In Kay's account of Smalltalk's early development, he cited key milestones attributed to Kaehler. According to Kay, along with Ingalls, Dave Robson, and Diana Merry, for instance, Kaehler successfully implemented the Smalltalk-76 system from scratch within a period of seven months. It constituted 50 classes that composed 180 pages of source code. Kaehler was also credited for designing the virtual memory system named Object-Oriented Zoned Environment (OOZE). This system gave Smalltalk more speed, and the development of a system tracer used to clone Smalltalk-76 since the technology can write out new virtual memories from their prior iterations. With Smalltalk, Kaehler worked closely with two future Turing Award winners. He began a lifelong professional association with Alan Kay, as described herein. Kaehler also co-authored a book, A Taste of Smalltalk, with University of California, Berkeley professor David Patterson, future leader of the RISC-V movement.

Apple

In March 1985, Kaehler moved to Apple as a researcher. He became involved in the development of Macintosh computers, primarily providing technical support. However, Kaehler was more noted for improving other technologies such as the company's HyperCard system from 1985 to 1987. This is a tool that allows users to create entertainment and instructional content. Kaehler added an interface that made it possible to control videodiscs. In 1996, while at Apple, Kaehler received a US patent for co-inventing user interface intermittent on-demand (pop up) halos around objects, with buttons to manipulate that object.

Squeak Kaehler also became part of the open-source software community-supported Squeak Central Team in 1996, which also included Ingalls, John Maloney, Scott Wallace, and Andreas Raab. It was initially developed out of the Smalltalk-80 at Apple Research Laboratory and was later continued at Walt Disney Imagineering. Squeak was developed as an open and highly-portable language that is written fully in Smalltalk and included the EToys system, which allows children to see the software operation. The use of Smalltalk technology allows Squeak to be easier to debug, analyze, and change. Kaehler was credited for writing the code of the platform's painting system, Squeak Paintbox, and other EToys pilot versions.

Personal life In 1982, Kaehler wed Carol Nasby, who also worked at Apple for several years, wrote the first Macintosh Owners Guide, built the HyperCard Help System for version 1.0, and wrote the book HyperCard Power. In 1991, she died from complications of Type 1 diabetes. In 1998, he wed his second wife Cynthia. She was a former preschool teacher for 25 years, and an artist who made fused glass pendants for necklaces and broaches. They lived in Las Vegas, Nevada and had three children. In 2020, she died from cancer.

See also List of computer scientists List of programmers

References

External links Official website

Worked examples

Example 1 — a first encounter with Ted Kaehler

Start with the simplest possible case. Write down what Ted Kaehler 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 Ted Kaehler 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 Ted Kaehler 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 Ted Kaehler

In research: Ted Kaehler 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 Ted Kaehler 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: Ted Kaehler is common in secondary-school and first-year university syllabi. It links to neighbouring topics 1950 births, 20th-century American scientists, 21st-century American scientists, so understanding it makes those chapters shorter.
In everyday life: Look for Ted Kaehler 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 Ted Kaehler in 20 minutes

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

Frequently asked questions

What is Ted Kaehler in simple terms?

Why does Ted Kaehler 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 Ted Kaehler?

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 Ted Kaehler.