Barry W. Boehm

Framework and initial phases for computer performance improvement

Computer performance analysis often evokes an image of a hardware monitor dictating a particular hardware modification that doubles the systems capacity. In fact, it usually involves measuring system performance, but is not necessarily limited to the use of hardware monitors, nor does it necessarily involve a hardware modification. It also includes the use of such measurement data sources as software monitors, computer accounting systems, sign-in logs, maintenance logs, and observations from computer operators, system programmers, and users. No specific improvement modification (hardware, etc.) is dictated by the measurements; the analyst must (1) formulate hypotheses about possible inefficiencies and/or bottlenecks in the system by gathering and analyzing computer performance data and (2) suggest alternative system modifications that will improve performance. Such modifications may deal with computer hardware, but they may also deal with computer software, operational procedures, job scheduling, job costing, and any system elements that directly or indirectly affect total system performance.

Conference results

Although diversity of opinion characterized many of the individual discussions, the conference yielded a surprisingly strong degree of consensus on a series of four major related points.

Curve fitting and editing via interactive graphics

The system described here allows a user to enter a curve into an IBM 360/40 computer via a RAND tablet [1], and interactively to specify various ways of fitting, editing and displaying the curve on an IBM 2250 scope (see Fig. 1). It was developed primarily as a tool to extend the analysis of multivariate function representation (described by Boehm [2]) from tabular methods to polynomial methods. We decided to use an interactive graphics approach for three main reasons: 1. Experience has shown that much time is spent visually editing curves for input errors; this used to be done on an SC-4020 with one-day turn-around. 2. We wanted to experiment rapidly with choice of form, as multivariate functions are hard to classify in terms of representability. 3. The facility was available, along with a basic software support package.

Interactive trajectory analysis: the graphic rocket system

This paper describes an operational interactive computer graphics system, called Graphic ROCKET, currently being used as a performance analysis aid for preliminary design and evaluation of space vehicle systems. It provides means for rapidly specifying and evaluating the performance of a wide range aerospace vehicle designs and flight plans.

POGO: Programmer-oriented graphics operation

POGO is an operational interactive graphics system which allows one to create inter- active graphics programs with relatively little elapsed time, programming expertise, or graphics expertise. It features a design program for composing CRT control “pages” by example instead of by programming, and facilities for cleanly inter- facing such pages with FORTRAN computational and control subroutines, and with a standard set of curve input and display pages. The presentation will include a description of our development and usage experience, and a film showing the use of POGO in creating interactive graphics programs for trajectory analysis, for analysis of fluid balance in the human body, and for creating parts of POGO itself.