Byte, junio del 85

Pues nada, seguimos con nuestro proyecto de leernos cada mes la revista Byte… de hace cuarenta años. Y le toca el turno al número de junio de 1985. Encontraréis todos los números en esta colección de archive.org, y el que leemos hoy, en concreto, dedicado a las técnicas de programación.

Portada de la revista Byte de junio de 1985. La imagen de portada es un cubo de Rubik en que cada una de las pequeñas caras del cubo es un una palabre clave informática. Entre ellas, tenemos char, DUP, UNIT, CAT, REM, puts, NULL, GREP, COND, FOR, GOTO...

Tampoco es que sea el número de mi vida, pero tiene sus cosillas. La primera en que me paro tiene que ver con accesibilidad:

Products Will Aid Visually Disabled Computer Users

Computer Aids, Fort Wayne, IN, introduced several microcomputer products for the disabled. One product, Small-Talk, uses a modified Epson HX-20 and a speech synthesizer to allow blind users to perform word-processing tasks. With a printer, microcassette tape drive, and special word-processing software, the computer will cost about $2000.

Que sí. Que hace décadas que hay gente que piensa en usar la informática para ayudar a las personas con discapacidad (en este caso visual). Lástima que tanta otra gente se olvide del tema.

Siguiente parada, anuncio de ordenador de esos que te hace añorar el diseño industrial ochentero:

Anuncio a doble página de la marca apricot. En la página izquierda, los restos de un albaricoque que alguien se acaba de comer, con el texto Past. A la derecha, un albaricoque entero, con el texto Present and Future. En la esquina inferior izquierda de la página, una miniatura de un ordenador de diseño ochentero. Más detalles en la siguiente imagen.

¿Me vais a decir que no es precioso? Bueno. Me vais a decir que no se ve. Hagamos un enhance it:

Zoom de la imagen anterior. Tenemos un portátil en tres piezas. La primera tiene la pantalla (de fósforo verde) y seguramente la CPU. El teclado está en otra pieza, y hay una tercera pieza con lo que parece ser un trackball. La imagen viene con el texto The APricot Portable. 521K RAM, 720K diskette. 80x25 line LCD. MS-DOS. $2495

¿Es o no precioso el Apricot Portable? Había salido a la venta en octubre del 84 y, recomonozcámoslo, le daba sopas con honda a los portátiles de la época (incluido mi adorado SX-64). Ni siete kilos, pesaba. Y las piezas separadas se comunicaban ¡por infrarrojos! ¡El futuro! ¡En 1984! Hasta tenía reconocimiento de voz (aunque habría que poner «reconocimiento» entre toneladas de comillas: dice la Wikipedia que se le podían entrar 4096 palabras, 64 de las cuales simultáneamente en memoria). Y su MS-DOS pasaba de los famosos 640 Ks (para llegar a 768, tampoco nos emocionemos más de la cuenta). En cualquier caso, una preciosidad.

Seguimos avanzando y nos encontramos con otro anuncio:

Anuncio. Vemos la foto de una pantalla de un PC de IBM, con lo que parece una interfaz gráfica del estilo de un Windows antiguo y un programa de dibujo en el que alguien ha creado lo que parece un post it con la palabra hi escrita a mano

¿Qué es eso de GEM? Aquí, otra versión del anuncio:

De nuevo, una pantalla de un IBM PC, con un entorno gráfico de ventanas (también se ve un ratón en la página) y la caja de un software, GEM Desktop, y su precio ($49.95). Se explica que el software era, efectivamente, un entorno gráfico para usar los PCs de IBM sin tener que teclear comandos crípticos.

GEM era el entorno gráfico que desarrolló Digital Research (la compañía de CP/M, fundada en 1974 y que sería adquirida por Novell en 1991 ) principalmente para los Atari ST, pero también para PCs con MS-DOS, entre otros. Y es ver una captura de GEM y que se me caiga la lagrimita. Esnif.

Volviendo a nuestro clásico «¿créias que esto era nuevo?», hoy toca…

Turning a common AI operation into silicon

Logic programming is a staple of artificial-intelligence (AI) software and is often dominated by the pattern-matching process of unification (see the "Resolution and Unification" text box on page 173). In fact, when logic-programming languages such as Prolog and LOGLISP are used, as much as 50 to 60 percent of a computer's processing time is spent on unification. When a single algorithm is used that frequently, it is natural to consider implementing it as custom hardware. When that same algorithm lends itself to parallelism and concurrency because of its recursive, treesearch characteristics, it practically begs for VLSI (very large scale integration) implementation.

SUM History

Professor lohn Oldfield and a team of researchers at Syracuse University are developing the SUM (Syracuse Unification Machine), a coprocessor for computers geared toward AI programming. The project combines the resources of the Syracuse CIS (Computer and Information Science) department. ECE (Electrical and Computer Engineering) department, and the CASE Center (Computer Applications and Software Engineering Center, set up by New York State). Key SUM individuals are Dr. Oldfield himself (who contributed CAD [com-

puter-aided design| and VLSI expertise). Professor Alan Robinson (who is the head of the logic-programming efforts at Syracuse), and Kevin Greene (who made the initial designs of the SUM). Because of a famous 1965 paper, Dr. Robinson is often credited with inventing unification. He is more modest, pointing to the work of Herbrand in the 1930s and the studies of Prawitz and Kenger concerning unification. Dr. Robinson contends that he was just the first to formalize the unification process and apply it to resolution.

In 1981, the Syracuse CIS logic-programming group learned that Caltech (California Institute of Technology) student Sheue-Ling Lien had designed a chip that embodied Dr. Robinson's original unification algorithm (see the "Unification on a Chip" text box, page 1 74). Dr. Robinson and his colleagues were somewhat taken aback that someone else had taken this step. Lien's report was a major inspiration for the development of the SUM, even though the chip it described was never actually made. Because ECE had been developing custom VLSI

chip-design capability and had a strong logic-programming group, combining the pursuits "seemed a natural thing" according to Dr. Oldfield.

Coprocessor Strategy

As Dr. Oldfield explains, "Although we started talking about a unification chip, following along the lines of the Caltech one. it soon became fairly clear that at present levels of integration that was fairly ridiculous. You could make a chip, but it would be limited to solving such small problems that it wouldn't be worthwhile." The SUM group wanted to design a full-blown, practical processor. Besides. Lien's chip used Dr. Robinson's original 1965 algorithm. Much more efficient algorithms have been developed since.

When they realized that a single chip wasn't realistic, the members of the group looked at the possibility of a coprocessor, initially for the LMI

Sí, queridas, podríais pensar que TPUs y NPUs y demás son una cosa acabada de inventar, pero cada vez que la IA se pone de moda, alguien piensa en hardware para acelerarla…

Siguiente cosa que me ha interesado: ¿cómo elegir lenguaje de programación?

CHOOSING A PROGRAMMING
LANGUAGE

by Gary Elfring

It's a three-step process

IF YOU WERE a carpenter building a new house, the first thing you would do would be to collect your tools. The tools you'd select would vary depending on the type of job. The same thing should be true if you are a programmer. You have a wide range of tools available, and you just choose the right tools for the job. Your tools are the languages that you program in and the environments needed to support those languages.

How do you go about selecting the right tool for the job? There are more programming languages available for microprocessors than most people could learn in a lifetime. What you need is a methodology that can be used to select one language from all the rest for a given application.

This article presents a practical method for comparing programming languages. It has an inherent bias toward compiled high-level languages. Compiled languages are faster than interpreted ones, and most interpreted languages also offer a compiler version. Since program speed is often an issue, I chose compilers over interpreters.

The actual process of evaluating a group of programming languages can be broken down into three major steps. The first step is to characterize the application the language is being selected for. Then you must identify the features that a language should have in order to deal with the previously described application. Finally, you should take into account practical considerations to further narrow down the language selection.

The Application

You can't choose a tool unless you know what you intend to do with it. You have to describe your application. Once you have this information you can then proceed to determine whether or not the existing language choices are the right tools for the job. To describe an application, you must consider both the type and size of the application. These questions must be answered before you can proceed any further in the language evaluation:

What is the type or class of application? What level of language is needed?

There are a number of different classes of program applications. An application can belong to a single class or several. Identifying the class of your application is relatively simple and helps narrow the list of acceptable languages. Some of the more common classes include scientific, business, and system programming; text processing; expert systems; and real-time control.

Most programming languages are better suited to solving one particular class of problem than another. COBOL is one example. While it is easy to write maintainable business programs with COBOL, no one would expect to use this language to solve real-time control problems.

Another consideration is the level of programming that the application will require. If you need low-level control of various machine-dependent features, then a very high level language...

La cosa comienza dando preferencia a compilados sobre interpretados por temas de velocidad (cosa más importante hace cuarenta años que ahora, que les pregunten a JavaScript y Python). Sigue proponiendo que el tipo de programa es muy importante (y dando COBOL como ejemplo de lenguaje para aplicaciones de negocios), y a continuación proponiendo si lenguajes de alto o bajo nivel… Comencé a leer el artículo pensando que lo que dijese sería siendo bastante actual. Curiosamente, donde uno esperaba más estabilidad… va a ser que no. Pero claro, entonces llega este artículo sobre componentes reutilizables:

SOFTWARE-ICs

by Lamar Ledbetter and Brad Cox

A plan for building reusable software components

THE SOFTWARE WORLD has run headlong into the Software Crisis—ambitious software projects are hard to manage, too expensive, of mediocre quality, and hard to schedule reliably. Moreover, all too often, software delivers a solution that doesn't meet the customers' needs. After delivery, if not before, changing requirements mean that systems must be modified.

We must build systems in a radically different way if we are going to satisfy tomorrow's quantity and quality demands. We must learn to build systems that can withstand change.

Some system developers are already building software much faster and of better quality than last year. Not only that, the systems are much more tolerant of change than ever before, as a result of an old technology called message/object programming. This technology, made commercially viable because of the cost/performance trends in hardware, holds the key to a long-awaited dream— software reusability. A new industry is developing to support the design, development, distribution, and support of reusable Software-ICs (integrated circuits). A forthcoming series in UNIX/World will address message/object programming.

Message/Object Programming and software-ICs

In this article we'll look at the concepts of message/object programming and how they support the building of "Software-ICs," as we call them, by satisfying the requirements for reusability.

A Software-lC is a reusable software component. It is a software packaging concept that combines aspects of subroutine libraries and UNIX filter programs. A Software-IC is a standard binary file produced by compiling a C program generated by Objective-C.

The notion of objects that communicate by messages is the foundation of message/object programming and fundamental to Software-ICs. An object includes data, a collection of procedures (methods) that can access that data directly, and a selection mechanism whereby a message is translated into a call to one of these procedures. You can request objects to do things by sending them a message.

Sending a message to an object is exactly like calling a function to operate on a data structure, with one crucial difference: Function calls specify not what should be accomplished but how. The function name identifies specific code to be executed. Messages, by contrast, specify what you want an object to do and leave it up to the object to decide how.

Requirements for Reusability

Only a few years ago, hardware designers built hardware much as we build software today. They assembled custom circuits from individual electrical components (transistors, resistors, capacitors, and so on), just as we build functions out of low-level components of programming languages (assignment statements, conditional statements, function calls, and so on). Massive reusability of hardware designs wasn't possible until a packaging technology evolved that could make the hardware environment of a chip (the circuit board and adjoining electrical components)...

Ojo a los dos primeros párrafos:

El mundo del software ha chocado con la Crisis del Software: los proyectos ambiciosos son difíciles de gestionar, demasiado caros, de calidad mediocre y difíciles de programar con fiabilidad. Además, con demasiada frecuencia, el software ofrece una solución que no satisface las necesidades de los clientes. Tras la entrega, o incluso antes, los cambios en los requisitos obligan a modificar los sistemas.

Debemos construir sistemas de una forma radicalmente diferente si queremos satisfacer las demandas futuras de cantidad y calidad. Debemos aprender a construir sistemas que resistan el cambio.

¿Escritos en 1985? ¿1995? ¿2025? ¿Nos jugamos algo a que los podremos reutilizar sin tocar una coma en 2065?

En fin… Si queréis saltar de este mes de junio del 85 a nuestra relectura del número de mayo, aquí lo teneís. y el mes que viene, más (espero).

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