TweetFollow Us on Twitter

About Modula-2
Volume Number:1
Issue Number:5
Column Tag: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;
      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;
   WriteLn; WriteCard(count,6); WriteString(‘ Primes’)
END Prime.

Modula-2 Benchmarks

A Comparison between versions and machines


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


Community Search:
MacTech Search:

Software Updates via MacUpdate

OmniPlan 3.0 - Robust project management...
With OmniPlan, you can create logical, manageable project plans with Gantt charts, schedules, summaries, milestones, and critical paths. Break down the tasks needed to make your project a success,... Read more
Yummy FTP 1.11 - FTP/SFTP/FTPS client fo...
Yummy FTP is an FTP + SFTP + FTPS file transfer client which focuses on speed, reliability and productivity. Whether you need to transfer a few files or a few thousand, schedule automatic backups, or... Read more
Tweetbot 2.1 - Popular Twitter client. (...
Tweetbot is a full-featured OS X Twitter client with a lot of personality. Whether it's the meticulously-crafted interface, sounds and animation, or features like multiple timelines and column views... Read more
MacPilot 8.0 - Enable over 1,200 hidden...
MacPilot gives you the power of UNIX and the simplicity of Macintosh, which means a phenomenal amount of untapped power in your hands! Use MacPilot to unlock over 1,200 features, and access them all... Read more
Typinator 6.7 - Speedy and reliable text...
Typinator turbo-charges your typing productivity. Type a little. Typinator does the rest. We've all faced projects that require repetitive typing tasks. With Typinator, you can store commonly used... Read more
Adobe Lightroom 6.2 - Import, develop, a...
Adobe Lightroom is available as part of Adobe Creative Cloud for as little as $9.99/month bundled with Photoshop CC as part of the photography package. Lightroom 6 is also available for purchase as a... Read more
ForeverSave 2.1.4 - Universal auto-save...
ForeverSave auto-saves all documents you're working on while simultaneously doing backup versioning in the background. Lost data can be quickly restored at any time. Losing data, caused by... Read more
VueScan 9.5.27 - Scanner software with a...
VueScan is a scanning program that works with most high-quality flatbed and film scanners to produce scans that have excellent color fidelity and color balance. VueScan is easy to use, and has... Read more
AirPort Utility 6.3.6 - Set up and manag...
Note: Most recent release available only within OS X 10.11 El Capitan update. Use AirPort Utility to set up and manage your Wi-Fi network and AirPort base stations, including AirPort Express, AirPort... Read more
Quicksilver 1.3.1 - Application launcher...
Quicksilver is a light, fast and free Mac application that gives you the power to control your Mac with keystrokes alone. Quicksilver allows you to find what you need quickly and easily, then act... Read more

Super Sharp (Games)
Super Sharp 1.1 Device: iOS Universal Category: Games Price: $1.99, Version: 1.1 (iTunes) Description: Your finger has never been so sharp! Cut with skill to complete the 120 ingenious physics levels of Super Sharp and become a cut... | Read more »
Assembly - Graphic design for everyone...
Assembly - Graphic design for everyone 1.0 Device: iOS Universal Category: Photography Price: $2.99, Version: 1.0 (iTunes) Description: Assembly is the easiest most powerful design tool on the App Store. Create anything you can... | Read more »
YAMGUN (Games)
YAMGUN 1.0 Device: iOS Universal Category: Games Price: $2.99, Version: 1.0 (iTunes) Description: The invasion has begun! Protect the walls of the citadel against waves of enemies! But watch out, you will soon run out of ammo...... | Read more »
Royal Bounty HD (Games)
Royal Bounty HD 1.0 Device: iOS Universal Category: Games Price: $4.99, Version: 1.0 (iTunes) Description: New World Computing Approved "Hi Guys! looks good so far! keep up the good work. I worked on HoMM 3 and 4 creating all of the... | Read more »
Swords & Crossbones: An Epic Pirate...
Swords & Crossbones: An Epic Pirate Story 1.0 Device: iOS Universal Category: Games Price: $4.99, Version: 1.0 (iTunes) Description: | Read more »
Camel Up (Games)
Camel Up 1.0.0 Device: iOS Universal Category: Games Price: $4.99, Version: 1.0.0 (iTunes) Description: | Read more »
The Martian: Bring Him Home (Games)
The Martian: Bring Him Home 1.0 Device: iOS Universal Category: Games Price: $2.99, Version: 1.0 (iTunes) Description: Based on the best selling novel and critically acclaimed film, THE MARTIAN tells the story of Astronaut Mark... | Read more »
This Week at 148Apps: September 21-30, 2...
Leap Into Fall With 148Apps How do you know what apps are worth your time and money? Just look to the review team at 148Apps. We sort through the chaos and find the apps you're looking for. The ones we love become Editor’s Choice, standing out above... | Read more »
Tweetbot 4 for Twitter (Social Networki...
Tweetbot 4 for Twitter 4.0 Device: iOS Universal Category: Social Networking Price: $4.99, Version: 4.0 (iTunes) Description: *** 50% off for a limited time. *** | Read more »
Mori (Games)
Mori 1.0 Device: iOS Universal Category: Games Price: $2.99, Version: 1.0 (iTunes) Description: Stop, rewind and unwind with Mori. Time is always running, take a moment to take control. Mori is an action puzzle game about infinitely... | Read more »

Price Scanner via

Save up to $350 with Apple refurbished iMacs
Apple has Certified Refurbished iMacs available for up to $350 off the cost of new models. Apple’s one-year warranty is standard, and shipping is free: - 27″ 3.5GHz 5K iMac – $1949 $350 off MSRP - 27... Read more
Mac Pros on sale for up to $300 off MSRP
B&H Photo has Mac Pros on sale for up to $300 off MSRP. Shipping is free, and B&H charges sales tax in NY only: - 3.7GHz 4-core Mac Pro: $2818.99, $181 off MSRP - 3.5GHz 6-core Mac Pro: $3699... Read more
5K iMacs on sale for up to $150 off MSRP, fre...
B&H Photo has the 27″ 3.3GHz 5K iMac on sale for $1899.99 including free shipping plus NY tax only. Their price is $100 off MSRP. They have the 27″ 3.5GHz 5K iMac on sale for $2149, $150 off MSRP... Read more
Twelve South Redesigns BookArc For Today’s Sm...
Twelve South has announced a redesigned version of their very first product, BookArc for MacBook. Tailored specifically for the newest generation of MacBooks, BookArc holds the new, smaller Apple... Read more
Phone 6s Tips & Tricks – Tips Book For iP...
Poole, United Kingdom based Tap Guides Ltd. has announced the release and immediate availability of iPhone 6s Tips & Tricks, an in-depth eBook available in the iBookstore that’s priced just $2.99... Read more
13-inch 2.5GHz MacBook Pro on sale for $994,...
Best Buy has the 13″ 2.5GHz MacBook Pro available for $994.99 on their online store. Choose free shipping or free instant local store pickup (if available). Their price is $105 off MSRP. Price valid... Read more
Is The iPad Pro Really A Serious Laptop Repla...
Probably not, at least for productive professionals and other power users. Steve Jobs declared that we’d entered the “post-PC Era” with the advent of the original iPad in 2010, a phrase we don’t hear... Read more
Wednesday Deal: 13-inch Retina MacBook Pros f...
Adorama has 13″ Retina MacBook Pros on sale for up to $130 off MSRP. Shipping is free, and Adorama charges sales tax for NY & NJ residents only: - 13″ 2.7GHz/128GB Retina MacBook Pro: $1199.99 $... Read more
uBar 3.0 for Mac OS X – Custom Dock Replaceme...
Brawer Software has announced the release of uBar 3.0, an important update to their popular app and window manager for Mac OS X. uBar allows users to position it whichever side of the screen they... Read more
13-inch 2.5GHz MacBook Pro (refurbished) avai...
Apple has Certified Refurbished 13″ 2.5GHz MacBook Pros available for $829, or $270 off the cost of new models. Apple’s one-year warranty is standard, and shipping is free: - 13″ 2.5GHz MacBook Pros... Read more

Jobs Board

*Apple* Retail - Multiple Customer Support P...
Job Description:Customer SupportSpecialist - Retail Customer Service and SalesTransform Apple Store visitors into loyal Apple customers. When customers enter the Read more
Software Engineer, *Apple* Watch - Apple (U...
…the team that is revolutionizing the watch! As a software engineer on the Apple Watch team, you will be responsible for building world-class applications and frameworks Read more
*Apple* Online Store UAT Lead - Apple (Unite...
**Job Summary** The Apple Online Store is a fast paced and ever evolving business environment. The User Acceptance Testing (UAT) lead in this organization is able to Read more
Hardware Systems Integration Engineer - *App...
**Job Summary** We are seeking an enthusiastic electrical engineer for the Apple Watch team. This is a design engineering position that entails working with Read more
Touch Validation Design (EE) - *Apple* Watc...
**Job Summary** Help launch next-generation Touch Technologies in Apple products. The Touch Technology team develops cutting-edge Touch solutions and technologies that Read more
All contents are Copyright 1984-2011 by Xplain Corporation. All rights reserved. Theme designed by Icreon.