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Ada Flyer A Biomedical Engineer's
View of Ada

Robert C. Leif,
Ada_Med Division of Newport Instruments
5648 Toyon Rd.
San Diego CA 92115
Tel: (619) 582 0437
Email: 76137.2164@CompuServe.com
Ensuring Dependability
Most of the medical devices I have worked on have included a significant software component. No simple solution exists to ensure that the software is dependable; however, using Ada provides a beginning. The United States Department of Defense (DoD) certifies that any compiler it "validates" has passed numerous tests in the validation test suite and Ada compiler vendors, such as Alsys, provide meaningful warranties. The use of Ada for developing expensive, dangerous weapons and for projects requiring a high level of safety, such as air traffic control and aircraft, has established an infrastructure of standards and experience for Ada programmers in specifying, designing, creating, and testing the software.

In the United States, if a manufacturer's 510K or Premarket Approval Form fails to substantiate that the product is safe and effective to the Food and Drug Administration's satisfaction, then the device cannot be sold in the country. Even after the sale, a patient can sue the manufacturer for malpractice and negligence if the device harms him or her. Now limited to the United States, the FDA's stringent guidelines are being tailored by the International Organization for Standardization (ISO) for the European Community. Hence, manufacturers will have a harder time avoiding tight standards for high quality by searching outside the United States for their markets.

Building an Instrument
The work on the algorithmic projects demonstrated the necessity for a true 32 bit 386 compiler. Studies indicated that, at the time, the only 386 compiler that could handle very large data structures, compile other test code (primarily acquired from STARS), and had a meaningful warranty was produced by Alsys. We purchased the Alsys Ada Compiler for developing the planned new mid range hematology instrument mostly on two factors: the excellent training courses available from Westley Mackey in software engineering and Eugene Bingue in Ada and AdaSAGE, and the fact that Alsys Ada produced true 32 bit code under Microsoft DOS that did not require overlays.

Two programmers, one who was already familiar with Ada, wrote the 2,833 Ada statements in two years; 996 statements were reused in the second program from the first. One obstacle was that Ada lacked support from third party vendors; for example, we had to develop a screen generator in house. In addition, we could not use the Thor tool or AdaSAGE because our new version of Alsys Ada was no longer compatible with the AdaSAGE libraries. However, the proof was in the pudding: the system’s software was finished before the hardware.

Both in terms of good manufacturing practices and of cost savings, Ada is, I believe, the correct language for medical devices. The improvements scheduled for Ada 95 will significantly facilitate further development of the instrument. The language's dependability will help manufacturers meet increasingly stringent and international standards and its portability makes it a logical choice for large biomedical projects where laboratories share code (such as in the human genome project and the space cytometer).

Department of Health and Human Services, Food and Drug Administration, 21 CFR Part 820, Medical Devices; Current Good Manufacturing Practice (CGMP) Regulations; Proposed Revisions; Request for Comments; Proposed Rule, Federal Register, 58, No.224, p 61952-61986 (November 23,1993).

R. C. Leif, I. Rosello, D. Simler, G. P. Garcia, and S. B. Leif; "Ada Software for Cytometry". Analytical and Quantitative Cytology and Histology 13, p 440-450 (1991).

R. C. Leif, J. Sara, I. Burgess, M. Kelly, S. B. Leif, and T. Daly, "The Development of Software in the Ada Language for a Mid Range Hematology Analyzer". Tri Ada `93, p 340-346 (1993A).

Copyright 1998. IIT Research Institute
All rights assigned to the US Government (Ada Joint Program Office). Permission to reprint this flyer, in whole or in part, is granted, provided the AdaIC is acknowledged as the source.
Form U120 biomed.txt

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