processors of the time.

I was struck by the irony of Knuth’s quote “I couldn’t stand to see my books so ugly” while spelling the name of his software “TeX” as he reminisced in the concluding part of Edward Feigen-baum’s interview with him “Donald Knuth: A Life’s Work Interrupted” (Aug. 2008). Microsoft products have evolved to the point where it’s now possible to render the correct spelling— “T_EX”—with subscript capital E and condensed, kerned character spacing and still manage to email it intact.

Whenever I stumble across “TeX,” I recall being scolded about that spelling in the introduction to its instruction manual.

michael Pelletier, merrimack, NH

include these Programming
Voices too

Though Peter J. Denning’s take on programming in his “Profession of IT” “Viewpoint” “Voices of Computing” (Aug. 2008) hit the mark, I’d like to acknowledge the importance of two other roles (voices):

Maintainer. Tries to understand, correct, and improve the “product,” though years later may pay dearly for poorly designed coding and a lack of documentation; and

Operations manager. Ensures everyday user service based on the availability of programs—the point of producing programs in the first place.

Requiring programmers to serve some of their apprenticeship as maintainers would help them understand what is important in the conception, design, implementation, and operation of programs. College and university courses that more accurately reflect all aspects of a program’s lifespan—from conception to decommissioning— would certainly contribute to their professional development.

Brian Kirk, Painswick, U.K.

 

how to Know When important Details are omitted Though the issue explored by Mark Guzdial, in “Paving the Way for Computational Thinking” (Aug. 2008) was important, it carries an equally important caveat. There is no reason to assume, a priori, that every important concept in

computation has a natural counterpart in precomputational thinking; some, indeed, do not.

This theme of making thinking about computation more natural has come up many times and, to my knowledge, always carried a tacit assumption that it can be taught in a way that is natural to newcomers. Guzdial’s examples of students’ propensity to omit an *else* clause in conditional statements illustrate the point. This is a case of giving ambiguous instructions and assuming the instruction-follower will correctly infer and carry out the appropriate action.

This cannot be fixed by making computers better at guessing how to resolve ambiguous or incomplete instructions. Developing the skill to recognize when important details are omitted and make them explicit is an indispensable part of computational thinking. Moreover, it is largely a new concept to students and thus not easily made natural to them.

There are, of course, aspects of computational thinking that can be made more natural, and doing so is a valuable goal when achievable. But any such attempt must be guided by constant vigilance about what can and what cannot be made natural. Otherwise, the results degenerate into just dumbing-down the material, making it easier, perhaps, but also misleading.

Rodney m. Bates, Wichita, KS

.hK Danger ‘under control’

We were surprised by the McAfee, Inc. research findings reported in the “News” item “Dangerous Web Domains” (Aug. 2008) and would like to add the following:

Old data. McAfee seemed to be describing the situation in 2008 but collected its data in 2007. While it said that 9.9 million Web sites were tested, most of the malicious ones were tested months before and may no longer exist;

New controls. Since March 2007, the Hong Kong Internet Registration Corporation Limited (HKIRC) has worked closely with the Office of the Telecommunications Authority of the Government of the Honk Kong Special Administrative Region, the Hong Kong Police, and the Hong Kong Computer Emer-

gency Response Team Coordination Centre to monitor and control suspicious Web sites using the .hk domain; and

Less phishing. Beginning in 2007, HKIRC adopted measures against suspicious Web sites. The number of reports of phishing and spamvertising using .hk thus decreased 92%, from an average of 38 per day in 2007 to three per day in 2008 (January to May).

In view of these measures, HKIRC

deems the situation under control. hong Kong internet Registration corporation Limited and hong Kong Domain name Registration company Limited; www.hkirc.hk/

 

The news item said malicious activity that might be associated with the .hk domain doesn’t necessarily take place in Hong Kong or China; “The owner of a domain name could theoretically situate his or her business anywhere.” McAfee declined to respond.—Ed.

no Best Way to Build
a mental model

The six-bullet software design process Robert L. Glass outlined as a trial-and-error activity in his “Practical Programmer” column “Software Design and the Monkey’s Brain” (June 2008) is better described as a sophisticated analysis-and-design activity that includes a trial-and-error strategy, given that the purpose of the activity is to analyze a problem and create an automated solution for it.

One root of the less-than-optimal progress in software (and software tools) lies in the column’s second bullet item—“Build a mental model of a proposed solution to the problem.” Nobody knows the one best way to build a mental model of a software solution. Supporting this conclusion are a large number of software strategies and artifacts, like structured programming, object-oriented programming systems, fourth-generation languages, network/ hierarchical/relational DBMSs, FORTRAN, COBOL, C, C++, and Java, some of which endure and some of which simply go extinct.

alex simonelis, montreal

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