Impact of ucsd pascal a view from the trenches
This presentation is the property of its rightful owner.
Sponsored Links
1 / 8

Impact of UCSD Pascal A View from the Trenches PowerPoint PPT Presentation


  • 72 Views
  • Uploaded on
  • Presentation posted in: General

Impact of UCSD Pascal A View from the Trenches. Roger Sumner. Before The Flood. Languages of the day: Fortran, COBOL, PL/I, RPG(!) Batch Mainframe Computers Punch cards, line printers, reel-to-reel tapes, overnight batch runs HUGELY EXPENSIVE

Download Presentation

Impact of UCSD Pascal A View from the Trenches

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.While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server.


- - - - - - - - - - - - - - - - - - - - - - - - - - E N D - - - - - - - - - - - - - - - - - - - - - - - - - -

Presentation Transcript


Impact of ucsd pascal a view from the trenches

Impact of UCSD PascalA View from the Trenches

Roger Sumner


Before the flood

Before The Flood

  • Languages of the day: Fortran, COBOL, PL/I, RPG(!)

  • Batch Mainframe Computers

    • Punch cards, line printers, reel-to-reel tapes, overnight batch runs

    • HUGELY EXPENSIVE

  • Minicomputers: Data General, DEC PDP-10, PDP-11, early Prime


Rise of the microcomputer

Rise of the Microcomputer

  • Assembly language

  • Basic (many dialects)

  • PL/M (Digital Research, Intel)

  • All limited to specific platforms

  • Very difficult to use

  • Open need: portable, easy to use, powerful language + compiler + system


Pascal as a new language

Pascal As A New Language

  • Other academic/niche languages: Simula, Euler, APL, Lisp, Algol; all on mainframes

  • Pascal was an academic language, too, but…

    • Simple enough for a modest-sized compiler

    • Powerful enough to write a compiler!

    • Pointers as a full-fledged data type

    • Enabled recursive data structures


Key features of pascal

Key Features of Pascal

  • Strong type checking - parameters & expressions

  • Pointer types

    • Safe, coupled to specific types (unlike “C” at the time)

    • Allows easily expressed recursive data structures

  • Very easy to like!

    • Structured programming wasn’t common in those days

    • UCSD Pascal popularized Pascal itself, which was then picked up by…

      • Microsoft Pascal

      • Borland Turbo Pascal

      • Apple Pascal (32-bit)

    • Adopted as a standard development language by many organizations, but…


Limitations

Limitations!

  • What Brian Kernighan saw as missing:

    • Strings, variable size arrays, logical ops

    • Separate compilation, libraries

    • Flexible I/O

    • An “escape” from compiler builtins & dogma

  • Lots of folks modified Pascal to solve these issues

    • Raising the ire of the theologians

    • But you gotta get your work done!


In the meantime the revenge of the phone company tpc

In the meantime… The revenge of The Phone Company (TPC)

  • C started its march towards domination

    • Low-level strings (OK with libraries)

    • Very flexible separate compilation (dangers, too!)

    • Pointers to functions

    • Very flexible I/O mechanism

    • Pointer/array semantics more powerful, but more dangerous

    • Lear Jet versus Piper Cub? (not in 1974!)


Pascal is dead its legacy lives on

Pascal is dead, its Legacy lives on

  • Pascal has gone the way of Latin

  • Borland Delphi = Pascal++ without credit

  • Key concepts live on, especially Java VM

    • Portable virtual machine

    • Friendlier, safer language than “C”

  • Strong type checking, scientific approach to program architecture


  • Login