1 / 18

FORTRAN

FORTRAN. The History of Fortran. Before Fortran there was a dark computing abyss Assembly was the only prominent language Mostly due to extreme memory limitations. continued. 1954-57 an IBM team led by John Backus Nothing new Extremely efficient optimizing compiler. continued.

aculpepper
Download Presentation

FORTRAN

An Image/Link below is provided (as is) to download presentation Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author. Content is provided to you AS IS for your information and personal use only. Download presentation by click this link. While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server. During download, if you can't get a presentation, the file might be deleted by the publisher.

E N D

Presentation Transcript

  1. FORTRAN

  2. The History of Fortran • Before Fortran there was a dark computing abyss • Assembly was the only prominent language • Mostly due to extreme memory limitations

  3. continued • 1954-57 an IBM team led by John Backus • Nothing new • Extremely efficient optimizing compiler

  4. continued • The compiler was the key • The scientific and military communities adopted Fortran as a standard • Fortran required less skill to program in • Programs could be developed in much less time • NASA used Fortran extensively

  5. Fortran II • 1958 • separate compilation of modules • Assembly modules could be “link-loaded” by Fortran modules

  6. Fortran III • Never released to the public • Assembly could be injected right in the middle of Fortran code • Lost HLL advantages when this happened

  7. Fortran IV • 1961 • Cleaned up Fortran II • Eliminated machine-dependent irregularities

  8. Fortran 66 • 1962-66 ASA standardized Fortran • First HLL standard in the world

  9. More Fortran • Fortran 77 improved on 66 • 1978… Disaster • Fortran was caught up in political entanglements (Fortran Saga) • 1991 gave Fortran 90 • Competition had caught up by this time • Fortran 95 added minor improvements

  10. Understanding Fortran 77 • Constants • Strings denoted with ‘ & ’ • Not “ & ” • Integers are 1, 2, 3 • Real numbers are -123.4, (0.6x10-3), 7E-3 • Variable types • 1-6 Characters per variable • All uppercase • All begin with an Alphabetic letter

  11. Understanding Fortran 77 • Variable Typing • INTEGER, CHARACTER, REAL • Ex. INTEGER AGE, AGE5 • Ex. CHARACTER NAME • READ Statement • Data input • Ex. READ *, NAME, AGE • PRINT Statement • Print data on the screen • Ex. PRINT *, ‘Hello ‘, NAME • Assignment Operator • AGE5 = AGE + 5

  12. Understanding Fortran 77 • Arithmetic Operators • Evaluation Order • **, * /, + - (highest to lowest) • Spaces are ignored • Ex. -1.0/X + Y/Z**2 • ML cannot do this

  13. Understanding Fortran 77 • Program Example

  14. Understanding Fortran 77 • Programs • Written in Columns • Layout of punch cards • Columns: • Comments: • Denoted by a ‘C’ or a ‘*’ in the 1st column

  15. Present Status • The Array Language • The abstract data type • Requirements

  16. The Future • Release Date • Standards

  17. Quote • “Fortran is likely to remain into the next century as, at the very least, a special-purpose scientific and numerical language for large-scale, computing-intensive applications; strengthen especially by its array capabilities, will be one of a small range of widely-used languages in general use.”

  18. Source • Michael Metcalf • Paris, 1999 September

More Related