TweetFollow Us on Twitter

About Modula-2
Volume Number:1
Issue Number:5
Column Tag:Modula-2

Modula-2

By John Bogan

Abstract: MODULA Corporation of Provo, Utah has shipped a $90.00 Beta site version of Modula-2 which runs reasonably well on a single disk 128K Macintosh. This paper attempts to make the case that Modula-2 deserves a thorough analysis to determine if it is the ideal standalone development language for serious commercial software on the Apple Macintosh. The conclusion of this paper is that Modula-2 will soon become the language of choice for farsighted software developers through the rest of the 1980’s and it is through the efforts of enlightened companies such as MODULA Corp. that this joyous result will come about.

A Short History of Modula-2

The history of Modula-2 is the history of its designer, Dr. Niklaus Wirth. We pick up the story in the late 1960’s when Dr. Wirth was a member of a large committee whose task was to design a successor to the language ALGOL-60, a highly popular language in Europe. ALGOL-60 is widely regarded as the inspiration for the discipline of Structured Programming which is the most significant breakthrough in software engineering in the past two decades. The result of this committee’s efforts was ALGOL-68, a kludge. No coherent design philosophy guided this effort resulting in a chaotic collection of features reminiscent of PL/I. In short, failure.

At this point Dr. Wirth abandoned the committee approach and decided to design his own language. Influenced by the structured programming theories of Dijkstra, Hoare and Dahl, Dr. Wirth set out to construct a language he could use to teach his own students the fundamentals of good programming. He began with some modest goals.

[“The development of the language Pascal is based on two principal aims. The first is to make available a language suitable to teach programming as a systematic discipline based on certain fundamental concepts clearly and naturally reflected by the language. The second is to develop implementations of this language which are both reliable and efficient on presently available computers.”] Pascal Report, page 1, 1974, Niklaus Wirth

The rest is history. As anyone who follows the computer industry well knows Pascal is one of the major influences on the software world today, particularly in the microcomputer world. To cite only one example the second largest manufacturer of personal computers in 1984 appears to have adopted Pascal as its standard design language. That company is, of course, Apple Computer, Inc. As I understand it most of the algorithms, data structures and techniques designed into the LISA and the Mac began life as Pascal programs.

But Pascal has significant flaws. Volumes have been written disparaging Pascal as a systems programming language and as a vehicle for writing applications of all stripes and colors. (Never mind that the language was never intended to do any of these things.) Further, and more disturbing, Pascal has been repeatly bastardized by its implementors with a wide variety of (incompatible) extensions. After a decade in the field there is no such thing as Standard Pascal any more than there is a tooth fairy. Nevertheless, many talented software people believe that even with its flaws Pascal is still the best practical general purpose language we have at our disposal. I believe this situation is about to change.

On with Wirth’s story. After largely washing his hands of Pascal Dr. Wirth turned his attention to multitasking and the problems of building large commercial programs using teams of programmers. As it happens Pascal is utterly unsuited for both of these activities. So Wirth designed himself a new, very simple language he called Modula. This language was never particularly practical it was more like a “hack” from one of the more gifted computer scientists around. However, it laid the groundwork for the concepts of seperate compilation, modularity and libraries.

In 1976 Dr. Wirth took a sabbatical from his mountain hideaway, Eidgenössische Technische Hochschule, Instut für Informatik, better known as ETH in Zürich, Switzerland and visited that fount of inspiration - Xerox PARC. As Mac enthusiasts we all know what that means. Personal workstations, high resolution bit maps, mice, windows, icons, Smalltalk etc. Less well known is the Xerox systems implementation language MESA. This language is a derivative of Pascal suitable for team implementation of low-level systems programs. The pieces were falling into place. Like many visitors to PARC Dr. Wirth came away with an inspiration.

Dr. Wirth was tired of the bitching and moaning surrounding Pascal.

[“If a language proves to be only marginally suitable for some application that was obviously not envisaged by its originator, we should muster the courage to build a new, truly adequate tool, instead of just grafting a fix onto the existing one.”] Byte, April 1983, pg. 386, Niklaus Wirth

Dr. Wirth’s inspiration was to build a new computer system from the ground up. A machine which would be programmed in one language from soup to nuts. From OS to text editor to graphics editor to who-knows-what, databases, spreadsheets, adventure games, what- ever. Recognizing that a one language machine would require the use of dangerous low-level facilities as well as the safety, convenience and productivity of the high level structured features he sifted through his encyclopedic knowledge of Pascal, Modula and MESA and in 1978 he defined his new language. To quote:

[“Modula [1], a small language ...featured a facility to partition programs into modules with explicitly specified interfaces. This was precisely the facility needed to allow the introduction of so-called low-level facilities in the high-level language, because it allowed you to encapsulate them and to constrain their danger- ousness to clearly delineated parts of a program. Hence, the choice for the new language was Pascal, augmented by the module and a few other facilites, and regularized by a more systematic syntax. Thus was born Modula-2.”] Byte, August 1984, pg. 146, Niklaus Wirth

Dr. Wirth had his ideal language. He then sat down with a couple of hardware types and some graduate students and built a bit-slice (AM2901) single-user high resolution graphic workstation with windows, mouse and multiple font editor with laser printer long before the Macintosh ever saw the light of day! He called his machine Lilith. The sole American distributor for the Lilith and the Modula-2 compiler which this machine is built around is MODULA Corporation of Provo, Ut., makers of Modula for Mac.

Modula Benchmark

The following program is an imple- mentation of the Sieve of Eratosthenes expressed in Modula Corporation’s version of Modula-2 for the Apple Macintosh 128K. The following results were obtained when this program was compiled and executed.

The source (Prime.MOD) = 1,617 bytes.

Compile time was -1:45

The M-code (Prime.REL) = 324 bytes.

Link time was -1:20

The execution module = 4,348 bytes.

Execution time was -1:11 or 71 seconds.

Modula-2 Compiler,Interpreter Ver. 1.0.

MODULE Prime;  (* Sieve of Eratos. *)
(* $R-  disable subrange and type conv *)
(* $T-  disable index checking *)
FROM InOut IMPORT WriteLn, WriteCard, WriteString;
FROM Terminal IMPORT ClearScreen;
CONST Size = 8190;
VAR i, prime, k, count, iter : CARDINAL;
      Flags : ARRAY[0..Size] OF BOOLEAN;
BEGIN
      ClearScreen;
      WriteLn; WriteString(“10 Iterations”);
      FOR iter := 1 TO 10 DO
           count := 0;
         FOR i := 0 TO Size DO Flags[i] :=                           
                        TRUE END;
           FOR i := 0 TO Size DO
                IF Flags[i] THEN
                     prime := i + i + 3;
                     k := i + prime;
                    WHILE k <= Size DO
                           Flags[k] := FALSE;
                           INC(k,prime)
                    END;
                  INC(count)
            END;
       END;
   END;
   WriteLn; WriteCard(count,6); WriteString(‘ Primes’)
END Prime.

Modula-2 Benchmarks

A Comparison between versions and machines

LEGEND

Code System Seconds

1. Lilith 4.24

2. Hamburg Vax 11/750 4.64

3. Logitech Eagle 6.90

4. ETH LSI-11 8.78

5. Logitech IBM PC 15.80

6. Volition Sage 66.14

7. Modula Macintosh 71.00

8. MRI Eagle 90.70

9. MRI IBM PC 203.60

10. Volition IBM PC 209.50

11. Volition Apple II 377.00

Source: “Seven Modula-2 Compilers Reviewed” by Terry L. Anderson Journal of Pascal, Ada & Modula-2 Vol.3 No.2

 
AAPL
$111.78
Apple Inc.
-0.87
MSFT
$47.66
Microsoft Corpora
+0.14
GOOG
$516.35
Google Inc.
+5.25

MacTech Search:
Community Search:

Software Updates via MacUpdate

LibreOffice 4.3.5.2 - Free Open Source o...
LibreOffice is an office suite (word processor, spreadsheet, presentations, drawing tool) compatible with other major office suites. The Document Foundation is coordinating development and... Read more
CleanApp 5.0.0 Beta 5 - Application dein...
CleanApp is an application deinstaller and archiver.... Your hard drive gets fuller day by day, but do you know why? CleanApp 5 provides you with insights how to reclaim disk space. There are... Read more
Monolingual 1.6.2 - Remove unwanted OS X...
Monolingual is a program for removing unnecesary language resources from OS X, in order to reclaim several hundred megabytes of disk space. It requires a 64-bit capable Intel-based Mac and at least... Read more
NetShade 6.1 - Browse privately using an...
NetShade is an Internet security tool that conceals your IP address on the web. NetShade routes your Web connection through either a public anonymous proxy server, or one of NetShade's own dedicated... Read more
calibre 2.13 - Complete e-library manage...
Calibre is a complete e-book library manager. Organize your collection, convert your books to multiple formats, and sync with all of your devices. Let Calibre be your multi-tasking digital librarian... Read more
Mellel 3.3.7 - Powerful word processor w...
Mellel is the leading word processor for OS X and has been widely considered the industry standard since its inception. Mellel focuses on writers and scholars for technical writing and multilingual... Read more
ScreenFlow 5.0.1 - Create screen recordi...
Save 10% with the exclusive MacUpdate coupon code: AFMacUpdate10 Buy now! ScreenFlow is powerful, easy-to-use screencasting software for the Mac. With ScreenFlow you can record the contents of your... Read more
Simon 4.0 - Monitor changes and crashes...
Simon monitors websites and alerts you of crashes and changes. Select pages to monitor, choose your alert options, and customize your settings. Simon does the rest. Keep a watchful eye on your... Read more
BBEdit 11.0.2 - Powerful text and HTML e...
BBEdit is the leading professional HTML and text editor for the Mac. Specifically crafted in response to the needs of Web authors and software developers, this award-winning product provides a... Read more
ExpanDrive 4.2.1 - Access cloud storage...
ExpanDrive builds cloud storage in every application, acts just like a USB drive plugged into your Mac. With ExpanDrive, you can securely access any remote file server directly from the Finder or... Read more

Latest Forum Discussions

See All

Make your own Tribez Figures (and More)...
Make your own Tribez Figures (and More) with Toyze Posted by Jessica Fisher on December 19th, 2014 [ permalink ] Universal App - Designed for iPhone and iPad | Read more »
So Many Holiday iOS Sales Oh My Goodness...
The holiday season is in full-swing, which means a whole lot of iOS apps and games are going on sale. A bunch already have, in fact. Naturally this means we’re putting together a hand-picked list of the best discounts and sales we can find in order... | Read more »
It’s Bird vs. Bird in the New PvP Mode f...
It’s Bird vs. Bird in the New PvP Mode for Angry Birds Epic Posted by Jessica Fisher on December 19th, 2014 [ permalink ] Universal App - Designed for iPhone and iPad | Read more »
Telltale Games and Mojang Announce Minec...
Telltale Games and Mojang Announce Minecraft: Story Mode – A Telltale Games Series Posted by Jessica Fisher on December 19th, 2014 [ permalink ] | Read more »
WarChest and Splash Damage Annouce Their...
WarChest and Splash Damage Annouce Their New Game: Tempo Posted by Jessica Fisher on December 19th, 2014 [ permalink ] WarChest Ltd and Splash Damage Ltd are teaming up again to work | Read more »
BulkyPix Celebrates its 6th Anniversary...
BulkyPix Celebrates its 6th Anniversary with a Bunch of Free Games Posted by Jessica Fisher on December 19th, 2014 [ permalink ] BulkyPix has | Read more »
Indulge in Japanese cuisine in Cooking F...
Indulge in Japanese cuisine in Cooking Fever’s new sushi-themed update Posted by Simon Reed on December 19th, 2014 [ permalink ] Lithuanian developer Nordcurrent has yet again updated its restaurant simulat | Read more »
Badland Daydream Level Pack Arrives to C...
Badland Daydream Level Pack Arrives to Celebrate 20 Million Downloads Posted by Ellis Spice on December 19th, 2014 [ permalink ] | Read more »
Far Cry 4, Assassin’s Creed Unity, Desti...
Far Cry 4, Assassin’s Creed Unity, Destiny, and Beyond – AppSpy Takes a Look at AAA Companion Apps Posted by Rob Rich on December 19th, 2014 [ permalink ] These day | Read more »
A Bunch of Halfbrick Games Are Going Fre...
A Bunch of Halfbrick Games Are Going Free for the Holidays Posted by Ellis Spice on December 19th, 2014 [ permalink ] Universal App - Designed for iPhone and iPad | Read more »

Price Scanner via MacPrices.net

The Apple Store offering free next-day shippi...
The Apple Store is now offering free next-day shipping on all in stock items if ordered before 12/23/14 at 10:00am PT. Local store pickup is also available within an hour of ordering for any in stock... Read more
It’s 1992 Again At Sony Pictures, Except For...
Techcrunch’s John Biggs interviewed a Sony Pictures Entertainment (SPE) employee, who quite understandably wished to remain anonymous, regarding post-hack conditions in SPE’s L.A office, explaining “... Read more
Holiday sales this weekend: MacBook Pros for...
 B&H Photo has new MacBook Pros on sale for up to $300 off MSRP as part of their Holiday pricing. Shipping is free, and B&H charges NY sales tax only: - 15″ 2.2GHz Retina MacBook Pro: $1699... Read more
Holiday sales this weekend: MacBook Airs for...
B&H Photo has 2014 MacBook Airs on sale for up to $120 off MSRP, for a limited time, for the Thanksgiving/Christmas Holiday shopping season. Shipping is free, and B&H charges NY sales tax... Read more
Holiday sales this weekend: iMacs for up to $...
B&H Photo has 21″ and 27″ iMacs on sale for up to $200 off MSRP including free shipping plus NY sales tax only. B&H will also include a free copy of Parallels Desktop software: - 21″ 1.4GHz... Read more
Holiday sales this weekend: Mac minis availab...
B&H Photo has new 2014 Mac minis on sale for up to $80 off MSRP. Shipping is free, and B&H charges NY sales tax only: - 1.4GHz Mac mini: $459 $40 off MSRP - 2.6GHz Mac mini: $629 $70 off MSRP... Read more
Holiday sales this weekend: Mac Pros for up t...
B&H Photo has Mac Pros on sale for up to $500 off MSRP. Shipping is free, and B&H charges sales tax in NY only: - 3.7GHz 4-core Mac Pro: $2599, $400 off MSRP - 3.5GHz 6-core Mac Pro: $3499, $... Read more
Save up to $400 on MacBooks with Apple Certif...
The Apple Store has Apple Certified Refurbished 2014 MacBook Pros and MacBook Airs available for up to $400 off the cost of new models. An Apple one-year warranty is included with each model, and... Read more
Save up to $300 on Macs, $30 on iPads with Ap...
Purchase a new Mac or iPad at The Apple Store for Education and take up to $300 off MSRP. All teachers, students, and staff of any educational institution qualify for the discount. Shipping is free,... Read more
iOS and Android OS Targeted by Man-in-the-Mid...
Cloud services security provider Akamai Technologies, Inc. has released, through the company’s Prolexic Security Engineering & Research Team (PLXsert), a new cybersecurity threat advisory. The... Read more

Jobs Board

*Apple* Store Leader Program (US) - Apple, I...
…Summary Learn and grow as you explore the art of leadership at the Apple Store. You'll master our retail business inside and out through training, hands-on experience, Read more
Project Manager, *Apple* Financial Services...
**Job Summary** Apple Financial Services (AFS) offers consumers, businesses and educational institutions ways to finance Apple purchases. We work with national and Read more
*Apple* Retail - Multiple Positions (US) - A...
Sales Specialist - Retail Customer Service and Sales Transform Apple Store visitors into loyal Apple customers. When customers enter the store, you're also the Read more
*Apple* Retail - Multiple Positions (US) - A...
Sales Specialist - Retail Customer Service and Sales Transform Apple Store visitors into loyal Apple customers. When customers enter the store, you're also the Read more
*Apple* Retail - Multiple Positions (US) - A...
Job Description: Sales Specialist - Retail Customer Service and Sales Transform Apple Store visitors into loyal Apple customers. When customers enter the store, Read more
All contents are Copyright 1984-2011 by Xplain Corporation. All rights reserved. Theme designed by Icreon.