A Machine-Independent Debugger--Revisited

Most debuggers are notoriously machine-dependent, but some recent research prototypes achieve varying degrees of machine-independence with novel designs. Cdb, a simple source-level debugger for C, is completely independent of its target architecture. This independence is achieved by embedding symbol tables and debugging code in the target program, which costs both time and space. This paper describes a revised design and implementation of cdb that reduces the space cost by nearly one-half and the time cost by 13% by storing symbol tables in external files. A symbol table is defined by a 31-line grammar in the Abstract Syntax Description Language (ASDL). ASDL is a domain-specific language for specifying tree data structures. The ASDL tools accept an ASDL grammar and generate code to construct, read, and write these data structures. Using ASDL automates implementing parts of the debugger, and the grammar documents the symbol table concisely. Using ASDL also suggested simplifications to the interface between the debugger and the target program. Perhaps most important, ASDL emphasizes that symbol tables are data structures, not file formats. Many of the pitfalls of working with low-level file formats can be avoided by focusing instead on high-level data structures and automating the implementation details.Comment: 12 pages; 6 figures; 3 table

Are Houses Too Big or In the Wrong Place? Tax Benefits to Housing and Inefficiencies in Location and Consumption

Tax benefits to owner-occupied housing provide incentives to consume housing, offsetting weaker disincentives of the property tax. These benefits also help counter the penalty federal taxes impose on households who work in productive high-wage areas, but reinforce incentives to consume local amenities. We simulate the effects of these benefits in a parameterized model, and determine the consequences of various tax reforms. Reductions in housing tax benefits generally increase efficiency in consumption, but reduce efficiency in location decisions, unless they are accompanied by tax rate reductions. The most efficient policy would eliminate most tax benefits to housing and index taxes to local wage levels

Interview with Robert D. Hanson, October 2, 1998

Robert D. Hanson, son of Gettysburg College President Henry W.A. Hanson, was interviewed on October 2, 1998 by Michael J. Birkner & David Hedrick. He discusses his father\u27s presidency, and what it was like to grow up in Gettysburg College\u27s White House. He also describes his experience as a student in the class of 1939--what it was like to be the son of the president as a student, fraternity life, academics, and his service in World War II. Length of Interview: 134 minutes Collection Note: This oral history was selected from the Oral History Collection maintained by Special Collections & College Archives. Transcripts are available for browsing in the Special Collections Reading Room, 4th floor, Musselman Library. GettDigital contains the complete listing of oral histories done from 1978 to the present. To view this list and to access selected digital versions please visit -- http://gettysburg.cdmhost.com/cdm/landingpage/collection/p16274coll

“No Shut-off” Policies and Natural Gas Consumption

Many U.S. states have regulations that prevent natural gas utility companies from turning off service to non-paying consumers. The goal of these policies, termed “no shut-off” (NSO) regulations, is to provide a guaranteed minimum level of residential comfort by reducing the marginal cost of consumption to zero for a period of time. This paper employs a difference-in-difference approach applied to residential U.S. Energy Information Administration data to evaluate whether NSO policies generate higher levels of gas usage. Our preferred specifications suggest that activation of a NSO policy increases natural gas consumption by between 4.7–4.8%, resulting in a total increase of between 66 and 67 billion cubic feet of natural gas consumed per winter season in covered states, at a value of as much as $950–970 million annually

The Effect of Simulated Hail Damage on Oats

With all of the advances in science and technology, the farmer is still helpless against the powers of nature. A natural disaster, such as a hailstorm, can seriously affect an individual fanner, or a small region. During the course of a growing season, the sum of these hailstorms can result in a substantial loss to the total farm economy. Hail insurance provides a way for farmers to protect themselves from losses due to hail, but the estimation of losses in a hailed field is a difficult job since the entire field is often hit leaving no check area from which to determine actual yield. It is to the benefit of farmers and insurers alike to have accurate and uniform adjusting procedures. The improvement of adjusting procedures has come A long way in small grains, especially in the case of wheat and barley. There are still several questions left unanswered in the case of oats, however. The major objective of this study was to determine the effect of simulated hail damage on oats at various stages of growth. This information may lead to the development of an adjustment table for use solely on oats; at the present time, there is one adjustment table for all small grains. In addition to providing a more factual basis for the adjustment of hail damage on oats, it will also increase our knowledge on the growth and development of the oat plant. Several treatments applied at various stages of growth were examined in an attempt to answer several of the questions raised about the adjustment of oats. The specific objectives were: 1) to determine the amount of blast caused by hail, 2) to determine whether a reduction in kernel weight occurs when the cu1m is broken below the head, and 3) to determine the percent of heads that fall prior to harvest. Answers to these objectives will help insurers make more accurate and uniform adjustments and provide farmers with just compensation for their losses