Eric Postpischil
High-Performance Software Engineer

Skills

• Programming Languages
  C, assembly languages, C++, Visual Basic, YACC, Lex, FORTRAN, Pascal, BLISS, BASIC, LISP, SNOBOL, SPL/3000, and APL (in order of decreasing fluency). Assembly languages include ARM, Intel 64 and IA-32, PowerPC/AltiVec, PDP-11, VAX-11, IBM 360/370, Digital Alpha, and Mips R-Series.
• Machines and Systems
  Machine-level programming experience with Intel 64 and IA-32 under macOS (Mac OS X), ARM under iOS, and PowerPC/AltiVec in both Mac OS X and embedded environments,
  Kernel internals experience with macOS and iOS, Unix (all Digital variants), PDP-11 RSX, and VAX-11 VMS.
  Application programming experience with Microsoft Windows.
  User and some programming experience with Unix (several variants), MS-DOS, TSO, and MPE III.
  Cursory knowledge of HP 3000, DECSystem 20, and Xerox Sigma 9.

Engineering Experience

• Senior Vector and Numerics Engineer, 30 August 2004 to 18 April 2018.
  Apple Incorporated, Cupertino, California.
  

  I implemented high-performance FFT routines and other routines for numerical processing. My work began with PowerPC and AltiVec but changed to Intel and ARM. I wrote high-performance SIMD code, often in assembly, including redesigning code and designing new algorithms to take advantage of new hardware. My FFT routines were world-class, at times beating Intel’s own software for speed. I created accurate and fast math library routines, including sinf, cosf, tanf, and their inverses. I wrote fast implementations of encryption (AES and SHA-1) and audio (SBC) routines. I helped develop new processor instructions, including proposing new instructions, implementing emulation code, and developing new code using the instructions. I implemented Intel emulation of ARM64 instructions, including integer and floating-point conversions with full support for rounding modes, subnormals, and exceptions. I served on the IEEE 754-2008 revision committee. I trained other engineers, diagnosed build issues and maintained complex software build procedures, and prepared software for special embedded and kernel environments. I managed the build procedures and configuration for a complex software product. I interviewed and evaluated employees for a corporate acquisition and for routine hiring.

• Software Engineer, 7 June 2004 to 29 July 2004.
  Electronic Arts-Tiburon, Maitland, Florida.
  

  I worked on physics simulation for Madden NFL. (I left this job after eight weeks because it was a great mismatch for my skills and interests.)

• High-Performance Software Engineer, 16 December 2002 to 11 September 2003.
  European Aeronautic Defence and Space Company (EADS), Ulm, Germany.
  

  I implemented FFT, IIR, and Advanced Encryption Standard routines in assembly language for high-performance computing on the PowerPC 7410.

• Sabbatical, August 2001 to November 2002.
  

  After working for 16 years and saving diligently, I quit to take a sabbatical. Aside from personal recreation, I learned Microsoft Windows programming, wrote a Windows application for a mathematical puzzle, caught up on C++ and the C++ Standard Template Library, taught a class, refreshed my knowledge of differential equations, started studying control theory, and did a lot of reading (fiction and non-fiction). The time was relaxing and educational.

• Mathematical Programmer, 8 December 1997 to 17 August 2001.
  Sky Computers (high-performance embedded computers), Chelmsford, Massachusetts.
  

  I made math library routines as fast as possible for high-performance signal and image processing. I optimized matrix multiplication, FFT, transcendental, and other routines in C and PowerPC/AltiVec assembly by analyzing mathematics, designing algorithms, and optimizing code for high speed with particular processor, cache, and bus characteristics. I also engineered calculations and algorithms to very precisely approximate trigonometric, logarithmic, and exponential functions.

• Senior Software Engineer, August 1991 to 1 December 1997.
  Unix Support Engineering, Digital Equipment Corporation, Nashua, New Hampshire.
  

  I held a variety of engineering roles related to Digital Unix (now Tru64 Unix, formerly OSF/1) and Ultrix, including:

  • Kernel Porting: I designed, implemented, and debugged Ultrix hardware memory management and cache support for the Mips R4000, and I assisted with the rest of the project to port Ultrix to the R4000.
  • Kernel Support: I debugged problems in the Ultrix and Digital Unix kernels, designed corrections, and ported corrections between versions. These included problems in virtual memory, interrupt priority levels, handling of floating-point exceptions, and the math library, as well as miscellaneous other software outside the kernel.
  • Technical Leader: I reviewed all Digital Unix patches for risks, accuracy, and completeness, and I conducted weekly technical discussions among the engineers.
  • Testing: I selected test suites to find bugs in Digital Unix patch kits, planned and led the testing, and diagnosed problems discovered by testing.

• Senior Software Engineer, March 1990 to August 1991.
  VMS Engineering, Digital Equipment Corporation, Nashua, New Hampshire.
  

  Assignments for porting VMS to the Alpha Architecture included porting modules in BLISS and Macro, designing and implementing macros to replace VAX BLISS built-ins, some redesign work for the new architecture (such as supporting new page sizes), and debugging.

• Senior Software Engineer, 25 March 1985 to March 1990, began as Software Engineer I.
  RSX Engineering, Digital Equipment Corporation, Nashua, New Hampshire.
  

  Tasks included design and maintenance work on many RSX components: portions of the operating system executive, Crash Dump Analyzer, Data Terminal Emulator, Micro/RSX File Transfer, Backup and Restore Utility, Postmortem Dump, Monitor Console Routine, Data Caching Manager, Shadow Recording, and VAX CoProcessor/RSX.

• Programmer, intermittent co-op position, ten months from September 1982 to August 1984.
  Harry Diamond Laboratories (later Adelphi Laboratory Center), Department of Defense, Adelphi, Maryland.
  

  Duties included translating various programs in BASIC and FORTRAN, writing TSO commands and general utilities (usually in FORTRAN), installing and debugging program products, and providing programming assistance.

• Technical Services Aide, June 1979 to August 1979.
  American Management Systems (later bought by CGI), Rosslyn, Virginia.
  

  Duties included providing technical aid to customers and verifying computer account records.

Teaching Experience

• Instructor, part-time, May 2002 to June 2002.
  Franklin Pierce College, Nashua, New Hampshire.
  

  Taught Foundations of Mathematics.

• Instructor, part-time, October 1996 to March 1997.
  Daniel Webster College, Nashua, New Hampshire.
  

  Taught Assembly Language Programming for the IBM PC.

Education

• Master of Science in Mathematics, with high distinction, December 1995.
  Rivier College, Nashua, New Hampshire.
• Bachelor of Computer Science, magna cum laude, November 1984.
  Rochester Institute of Technology, Rochester, New York.
• High School Diploma, June 1980.
  Eleanor Roosevelt Senior High School, Greenbelt, Maryland.
• GRE: 800 Analytical, 800 Quantitative, 790 Verbal. LSAT: 175. SAT: 800 Math, 610 Verbal.

Publication and Honors

• Postpischil and Gilbert, “There Are No New Homometric Golomb Ruler Pairs with 12 Marks or Less,” Journal of Experimental Mathematics 3 (1994) Number 2: 147-152.
• Top Scorer in Prince George’s County Mathematics League, Mathematics Association of America Honor Roll, Second in Maryland Mathematics League, and National Merit Semifinalist.