#breBytes Educación en línea, 1986

No puedo cerrar los #breBytes de septiembre de 1986 sin pararme aunque sea un minuto en la editorial de la revista…

EDITORIAL

College Credits Through Telecommunications

We urge colleges and universities to expand the practice of granting credits for courses taught through computer conferencing.

We have become aware of the need for computer-mediated instruction because BYTE's offices are located in a rural area. In order to advance professionally, members of our staff often need to take university courses to increase their knowledge of computer science or engineering. Unfortunately, we have no universities in easy commuting range that offer broad curricula in these fields of study. Some of our staff members have endured long commutes to continue their studies, but work loads are high at BYTE, and few employees can both do their jobs well and undertake regular university studies at distant sites.

The Instructional Medium

Direct observation has shown us that computer conferencing works as an instructional medium. We have seen tutorial topics spring up in many conferences on BIX. People learn about programming a new machine, for example, from volunteer teachers in distant areas. Sessions have the quality of free and open classroom discussions. The lack of face-to-face contact has not proved to be a hindrance.

We also know that instruction by computer conferencing has already worked in a university. The New School for Social Research, through an association with Connect Ed, has already taught graduate courses in media studies. Connect Ed uses the EIES conferencing software developed at the New York Institute of Technology by Murray Turoff. Some members of the BYTE staff visited the New School last year and spoke with students and teachers in the New School/Connect Ed program. All agreed that the system works. In their program, computer conferencing is supplemented by some actual classes. The requirement of occasional classes on campus is much less daunting than a long commute several times each week.

From the teacher's perspective, computer conferencing has some advantages as an instructional medium. It is easy to monitor attendance and to measure participation. Questions can be addressed to the whole class or to an individual. Since students can think as long as they wish before replying, dialogue conducted through computers is in some respects easier than spoken conversation. And, of course, shy and quiet people can always have their say in computer conferencing. The loud and aggressive can't drown them out. Examination tools to simplify the administration of exams on-line would not be difficult to create.

New Educational Opportunities

The use of telecommunications as a means of instruction can enable potential students in rural areas to gain access to outstanding teachers and scholars at major universities. If computer conferencing software is used, students can enjoy discussion and debate with students from different regions and backgrounds. The community of higher education will become accessible from remote areas as never before. Potential students in rural areas will enjoy unprecedented educational opportunities.

Moreover, computer conferencing can make many educational opportunities now beyond commuting range available to everyone. Even the opportunities available to those in urban areas will increase.

Cost Advantages

Sadly, the cost of higher education has now become prohibitive for many people. Instruction through computer conferencing can alleviate this situation by reducing expenses for both the university and the student. Universities will be able to add more students without building more dormitories and classrooms. The student can continue to live at home, incurring no new room and board expenses. This will effectively reduce the student's expenses to the amount of tuition, which can be exactly the same for on-line students as for on-campus ones. With tuition remaining the same, the university will experience no loss of revenue.

Combined Study

It seems likely that universities will be able to combine on-line instruction with on-campus instruction to provide improved courses. Daily on-line instruction could be supplemented by on-campus instruction— perhaps one or two Saturdays per month. Another intriguing possibility would be letting on-line students compete for on-campus scholarships to complete their studies. On-line interaction with prospective students might also permit both students and universities to make better choices in the admissions process.

The Big Step

We urge universities to offer credit courses through computer conferencing in order to test the limits of the medium and to learn how best to combine on-line and oncampus instruction. We believe computer conferencing can help preserve and extend educational opportunity in a time of prohibitive costs for many students and many universities. If universities do this, they will open their curricula to millions of potential students— personal computer users everywhere. Through their computers and modems, personal computer users, even those located in rural areas, will gain access to an enormous range of courses. Let's hope that universities and accrediting associations will seize this opportunity to extend educational programs.

— Phil Lemmons Editor in Chief

Ya habíamos hablado brevemente de educación en línea en 1986 en el último post dedicado a las Computer Chronicles, de este mismo mes, pero es maravilloso leer cómo, desde la revista, se animaba a las universidades al mundo del online, hablando de ruralidad, formación continua y lifelong learning, entre otros aspectos :-)

#breBytes La familia Motorola 68000

La vida de la familia 68000 de Motorola fue breve (dejó de fabricarse en 1996), pero intensa, siendo el procesador de nuestro adorado Amiga y del Atari ST, pero sobre todo la primera arquitectura sobre la que se construyeron los Macs (y el Lisa antes de eso). Apple se pasó a los PowerPC en 1994, y eso acabó con los 68k. Pero hace 40 años, en septiembre de 1986, la familia 68000 prometía muchísimo: lo suficiente como para ser portada de Byte.

Portada de la revista Byte de septiembre de 1986, dedicada a la familia 68000 de procesadores. Ilustran la portada algunos chips de la familia y pequeñas fotos de un Mac, un Atari ST y un Amiga 1000.

La revista le dedica un buen espacio a las diferentes máquinas 68000 (incluyendo un apartado dedicado a Unix), pero nosotros ya sabemos cuál era la mejor. Y es que, ¿qué otra máquina podía producir gráficos así?

Anuncio a página completa del Commodore Amiga, con una imagen a todo color de una ilustración de la imagen clásica del emperador egipcio Tutankamón.

Y claro, lo que más nos interesa de la sección es esta comparación entre el Amiga y el Mac, aunque está hecha desde el punto de vista del programador:

AMIGA VS. MACINTOSH

by Adam Brooks Webber

A programmer's comparison of the system calls on two 68000~based machines

I HELPED IMPLEMENT the True BASIC language system on the Macintosh. The project has been completed for some time now and we've all recovered our perspective and good humor, but at the time I felt that if I saw that smiling "Welcome to Macintosh" message one more time I would scream. It was in this frame of mind, on my way to see the Amiga for the first time, that I wrote out a list entitled "Why I Hate the Macintosh."

That incident led to this article. I have now completed the same project on the Amiga and have many gripes about that machine, too. In this article I compare the system software, of the two machines.

Implementing a language system is a good way to get to know a machine. True BASIC is not just a compiler and interpreter, it's a screen editor, a graphics program, and a number cruncher. It makes sounds, it prints, it manipulates files— in short, it uses most of a system's software. My comparison of the Macintosh and the Am\ga is necessarily limited, but I have tried to choose areas that are of general interest and that are representative of the differences between the two machines. These are the user interface, graphics primitives, printers and other devices, multitasking, and memory management.

The User Interface

The user interface of a system is usually examined from the user's point of view. You ask, "Is it intuitive? Is it powerful? Is it forgiving of error?" as you consider how to communicate with a program. I am interested in another point of view: What does a program have to do to communicate with the user? For some machines, communicating with the user means reading characters from the keyboard and writing text to the screen. Adding windows, menus, and mouse operations makes things more complicated, lust how complicated is shown by the Macintosh user interface software, which determines the structure of every Mac program more or less completely. The program must have a main loop that is executed as often as possible, usually 60 times a second. (One rule of thumb: The quality of system software is inversely proportional to the number of things a program must do "as often as possible.") The main loop checks for events like keystrokes, mouse clicks, and disk insertions and responds to them.

Responding to an event is usually a lot of work because the Mac's user interface software provides little assistance. Figure 1 shows, in pseudocode, a simple example of what a program must do to allow a window with a scroll bar to change in size— something that most Mac programs have to deal with. The system software does offer significant help in two areas of user interface: text editing and file access. TextEdit is a subsystem that provides a mechanism for displaying and editing text in a window. (True BASIC doesn't use TextEdit, but only because we have our own internal string-handling procedures.) For...

Nótese, por cierto, que el artículo está escrito por un graduado del Dartmouth College, el lugar de nacimiento de BASIC. La comparación, por cierto, es favorable al Amiga en cuanto a la programación de la interfaz, gestión de dispositivos, multitarea (no es una sorpresa enorme, teniendo en cuenta que el Mac no era multitarea en 1986) y gestión de memoria, y al Mac en lo que se refiere a primitivas gráficas. Pero esto no le salvaría la vida al Amiga, lamentablemente.

Un poco más adelante, en su Chaos Manor Jerry Pournelle seguía enamorado del Amiga y nos hablaba de ese clásico que fue Deluxe Paint (con el que se hizo el Tutankamón de aquí arriba, si no me equivoco, y que ocuparía el lugar en el imaginario que le dedicamos a Photoshop si viviésemos en la línea temporal correcta), pero ya veía los primeros pasos de la muerte de Commodore…

Amiga

My top pick of Spring COMDEX was the Amiga.

The Amiga did have some problems. For instance, when Ken Sheldon and l approached the Atari booth, they practically ran out to grab us; I stood in the Amiga booth for 15 minutes before anyone spoke to me. Atari software was demonstrated by hackers; most of the Amiga software was demonstrated by clerical employees from Commodore headquarters.

None of that really mattered. What was important was that the Amiga booth was jammed. 1 could feel the excitement. It reminded me of the early days of microcomputers. Moreover, once I got past the clerks and secretaries, there were plenty of real hackers.

Mike Lehman, who originally wrote Pascal MT+ and was later a vice president of Digital Research, has started a new company called Maxisoft. The product is MaxiPlan, a combination spreadsheet and database with chart capability. MaxiPlan knows how to do a lot of statistical calculations. It will make databases and charts, and it will talk to you through the Amiga's speech synthesizer. You'll spend a while on the manual— this thing is powerful, and the instructions can be complicated— but it's worth the investment. Highly recommended.

TDI Software has Modula-2 compilers for both the Atari and Amiga machines. The Atari version is a new release that fixes some problems with the original. Both versions work and should make it simpler to transport programs from Atari to Amiga. Longtime readers know I'm a Modula-2 fan; this is a reasonable implementation, and TD1 is working to make it better. The chief problem is the documentation: TDI needs to give more and better examples of just how to write and compile simple programs. Pournelle's law of software documentation: You can't have too many examples. I wish TDI would learn it.

The Amiga is known for its graphics; one of the best graphics programs is Deluxe Paint by Electronic Arts. Alas, they use an obnoxious copy-protection scheme. That's its only real fault; otherwise. Deluxe Paint is glorious. There's just very little you can't do with it. You can color-cycle portions of your drawing, so that waterfalls have running water; zoom in for fine details; and suchlike. It's a lot of fun. EA also has various games, some interesting, some boring.

Mindscape is another company that has developed some interesting Amiga software. The Halley Project is a spaceflight game that's part arcade but largely strategic; it helps to know something about planetary astronomy.

Activision has a whole bunch of Amiga software, including Music Studio, which 1 haven't much got into but which looks wonderful, and a series of illustrated text adventure games, including Hacker, which some say is the most difficult adventure of that type ever written.

In other words, there's a great deal of Amiga software: business, games, educational, programming tools. That, however, wasn't the real hit.

What was really impressive was the Amiga Sidecar, a box that turns an Amiga into a 99 percent PCompatible. Moreover, since the Amiga is a multitasking machine, they were able to run PC software as just one job. It was eerie to watch Flight Simulator running as if on a PC and still see the famous Amiga bouncing ball in the background and a word-processing program running in the foreground. The Sidecar has both 8088 and 8087 chips and is supposed to sell for significantly less than a thousand dollars. An Amiga plus Sidecar plus hard disk would be one of the most powerful combinations around, and I had no problem designating that the number one pick of Spring COMDEX.

Problems

One problem I've had with the Amiga is that while I kept hearing about all the new software for it, I never got any. Commodore's people sent catalogs, while the Atari people sent software. At COMDEX, Bob Pariseau, vice president for software development and one of the original Amiga development team, promised to fix all that. He also arranged to get me a Sidecar as soon as it was available. 1 left COMDEX convinced that the Amiga was likely to be the product of the year.

Two weeks later, Commodore laid off nearly 200 people, including Bob Pariseau. There were 55 Amiga people in the West Coast office; 20 were let go. Moreover, many who didn't leave immediately were put on notice; others, seeing the handwriting on the wall, quietly began sending out their resumes. The rumor I hear is that the investment bankers want Commodore to reduce their payroll by 50 percent; given Commodore's financial situation, the company is in no position to argue.

The question, then, is whether Commodore has— and can keep— enough high-tech people to support the Amiga properly. Commodore says they can. So do Amiga enthusiasts.

Me, I don't know. The situation is made vastly more complicated because many of those laid off were required to sign, as a condition for getting a few more severance benefits, a particularly severe— I would say obnoxious— nondisclosure agreement, the first term of which is that the agreement itself is secret. This has made it very difficult to get a decent picture of what has really happened at Commodore, and as I write this in early June I don't think anyone knows.

So. I like the Amiga, and I was much impressed by the enthusiasm of the Amiga people at COMDEX. Of course, even then the Commodore top brass must have known that many of those enthusiasts wouldn't be with the company two weeks later. By the time you read this, we may know the end of the story. I can't say I'm very fond of Commodore's management, but I do wish the Amiga well. It's a heck of a machine.

Y no me voy sin rescatar este anuncio, con el que se lanzaba lo que sería el estándar oro de los monitores durante muchísimos años: los NEC Multisync, capaces de trabajar con básicamente cualquier ordenador de la época, y que en esta, su primera encarnación, era capaz de alcanzar los 800 por 560 de resolución en sus 13 pulgadas :-).

Anuncio de la gama de monitores de tubo NEC Multisync

Un día de estos, más :-).

#breBytes C++

Aprovechando la canícula, seguimos con nuestra versión light del repaso a la revista Byte de hace cuarenta años. Y suerte que nos hemos pasado al modelo light, porque el número de agosto del 86 no venía especialmente fuerte. Pero no puedo saltarme la sección de crítica de libros, porque ahí tenemos uno de los clásicos de la informática, la presentación de C++ por parte del creador del lenguaje, Bjarne Stroustrup. (Si no he buscado mal, la cuarta y última (de momento) edición se publicó en 2011.)

Book Reviews

THE C++ PROGRAMMING LANGUAGE

Reviewed by G. Michael Vose

One of the tenets of evolutionary theory states that changes in the environment cause subtle mutations in an organism that transform it into a new organism. The changing nature of the hardware environment of computers causes an analogous evolution of programming languages. Bjarne Stroustrup's The C++ Programming language describes one recent language mutation.

Following the example of its parent, Brian W. Kernighan and Dennis M. Ritchie's The C Programming language (also known as K&R or the "white" book), this book defines the superset of C called C++. Both books provide multiple chapter tutorials for their respective languages as well as the languages' official reference manuals. Both contain examples and exercises for readers to solve.

Stroustrup's book assumes a familiarity with C (referring the beginning reader to K&R) but is nearly 100 pages longer than the white book. C++ adds considerably to the complexity of an already obtuse lexicon. Furthermore, C++ provides the tools to allow an objectoriented approach to programming in C.

Evaluating a book like Stroustrup's is difficult because microcomputer implementations of C++ are just becoming available (see the What's New section). I have no concrete experience with the language and no facility for using the tutorial sections of the book. Therefore, the judgments I can make are limited to two areas: Does the book adequately describe the concepts of C++, and do the C++ extensions seem useful? The historical significance of both the book and the language will have to wait for the judgment of some future reviewer.

People familiar with C instantly recognize the significance of the name C++. C's increment operator is symbolized using two plus signs (++). The suggestion is that C++ increments the power of the language, and this is certainly true. But for many C programmers, adding new constructs takes a back seat to fixing some of the awkward aspects of the original language. The authors provide some of these fixes.

Programmers enjoy using C because of the freedom of expression it provides due to a rich set of operators and great flexibility in declaring and manipulating data types. C++ increases this freedom substantially by offering additional data types and constructs that permit programmers to more easily build complex data structures (a process known as data abstraction). The emphasis in C++ is on types and structure.

Y me tenéis que reconocer que es divertido leer la crítica de un libro en la que el revisor te dice cosas como que C++ suma considerablemente a la complejidad de un léxico ya obtuso (no seré yo el que le lleve la contraria, pero pegarle así a C…), para a continuación explicarte que evaluar el libro es complicado en ausencia de implementaciones de C++ (vamos, sin haber probado el lenguaje), y después explicar qué es eso de los objetos en programación (la orientación a objetos, como paradigma, data de finales de los cincuenta (del siglo pasado), pero no se había prodigado mucho hasta la llegada de C++ y sus diferentes «primos» (por mucho que Smalltalk ya llevase unos cuantos años corriendo por el mundo)). No está mal, por cierto, permitirse darse el lujo de darle una collejita a nada más y nada menos que Stroustrup (en aquel momento no era la leyenda que es hoy, claro) por permitirse el lujo de usar palabras como «clase» antes de definirlas. Ni dudar (razonablemente, dada la juventud y novedad de la cosa) del éxito de un lenguaje que, cuarenta años más tarde, se disputa la segunda posición del ranking de lenguajes de TIOBE con «papá C».

Se publica la crítica, por cierto, dentro de un número dedicado a la programación orientada a objetos (ya os decía que el tema comenzaba a popularizarse en aquella época) en el que escribe, entre otros, el creador de Objective C, el lenguaje de desarrollo para Apple hasta nada más y nada menos que 2014.

Si queréis seguir hojeando el número, en la misma sección de libros se critica también el Mind Over Machine del filósofo Hubert Dreyfus y su hermano Stuart, algo menos famoso pero aún así profesor emérito en Berkeley, que se dice pronto. El libro argumenta (siempre según la crítica) que nunca tendremos una verdadera inteligencia artificial porque los ordenadores carecen de intuición. La historia no se repite, pero rima, dicen. El crítico también se fija en un capítulo dedicado a los temores sobre la implantación de la IA en la educación. 1986.

Y también se puede recomendar, creo, pero para valientes, el discurso del recientemente fallecido Tony Hoare (ya premio Turing por aquel entonces), Mathematics of programming. Por aquello de incidir en que lo que se publicaba en los ochenta en revistas generalistas de informática tenía en muchas ocasiones un nivel estratosférico, entre otras cosas.

En fin. Algún otro día, más, pero como muy pronto, en septiembre.

#breBytes El Commodore 128

Dijimos hace nada que dejaríamos de hacer nuestras lecturas mensuales de la revista Byte de hace cuarenta años, pero que amenazábamos con buscar alternativas. Isma señalaba en los comentarios lo que básicamente tenéis aquí abajo, y que a mí también se me había pasado por la cabeza: ya que el ejercicio de lectura en sí lo voy a seguir haciendo, no obligarme a hacer la entrada mensual y exhaustiva, pero, si aparece alguna noticia que me apetezca destacar, pues recogerla por el procedimiento habitual.

Y siempre hemos tenido la norma de que si aparece Commodore, lo recogemos…

The Commodore 128 Personal Computer System

The Commodore 128 personal computer includes 128K bytes of RAM and uses two microprocessors, a Z80 and a 6502-compatible chip, the 8502, which supports bank-switched memory. The C-128 includes dual video outputs, a four-voice sound synthesizer, 80-column RGB text output with its own independent 16K of video RAM (supporting 640 by 200 pixel resolution), and the 40-column VlC-11 chip, which supports 320 by 200 pixel high resolution sprite graphics.

On power-up, the C-128 enters the "native" or C-128. mode, which uses the 8502 processor, switchable between a 1- and 2-megahertz clock speed. The mode accesses the 128K of RAM using bank-switching techniques and allows you to use BASIC 7.0, an advanced BASIC In C-64 mode, you obtain full compatibility with the Commodore 64 but without access to any of the C-128's advanced features. Alternatively, you have a 2-MHz Z80based CP/M machine that supports bank-switched CP/M version 3.0 (CP/M Plus).

C-64 Mode

In C-64 mode. I had no trouble loading and running all my C-64 programs, including heavily copy-protected ones. There are three ways to switch to C-64 mode: In C-128 mode, you can type GO 64: you can hold down the Commodore logo key while powering up; or you can put a C-64 ROM cartridge in the expansion port. Note that you cannot leave the C-64 mode— the slight changes in the operating system necessary to implement the exit would reduce compatibility with the C-64. Note also that in C-64 mode, you will not normally be able to access any of the C-128's improved features, such as 80-column video output or high-speed disk drive usage with the 1571 drive.

There are only three slight differences between the C-64 mode and an actual C-64. The VIC-II video graphics chip has two extra registers. #47 and #48 (at locations 53295 and 53296). Register 47, a keyboard control register, uses 3 bits (the 5 highest bits are unused) to scan the extended key matrix. C-128 mode uses the register to read the numeric keypad, outboard cursor keys, Help, Tab, and other special function keys. To maintain full compatibility, the C-64 mode does not read the registers, but you could write code to read these keys even in C-64 mode.

Register 48 simply contains one bit that selects 1- or 2-MHz clock speeds. You can run many programs in C-64 mode at a 2-MHz clock rate, but you will not be able to access the VIC-II video chip; therefore, the screen will be blank. Additionally, the C-128 cannot communicate with its companion disk drive at this higher clock speed. The modem port and the sound chip do function properly when the system is running at 2 MHz. The third difference results from having two 64K-byte RAM banks. If you power up in C-128 mode and select bank or I, that will be the bank of RAM that the C-64 uses. Of course, this "difference" has no effect on compatibility with a stock C-64.

I have experienced no incompatibilities, and I am completely satisfied with the C-64 mode, but I have heard that one program. Commodore's International Soccer, does not function properly because of incorrectly read...

¿Iba perdida Commodore en el 86? Pues el Amiga y sus 16/32 bits ya llevaban una buena temporada en el mercado, pero el 64 seguía vendiendo de manera mas que considerable, y alguien tuvo la idea de crear un «monstruo» con doble CPU, heredero del 64 pero con unos masivos 128 Ks de RAM y el doble también de velocidad de procesador, hacerlo compatible con el 64 hasta ser un 64 si se le pedía con un mínimo de amabilidad (G0 64, eran las palabras mágicas) y, por si dos ordenadores en uno no fuesen suficiente, un modo CP/M, cuando el CP/M seguía siendo un sistema operativo más que interesante.

Sobre el papel, una idea muy interesante: una máquina capaz de ejecutar la infinidad de soft que se había desarrollado para el 64 y para las máquinas CP/M, y de ir más allá con el 128. En la práctica, Commodore no vendió ni una máquina más que si hubiese seguido con el 64, nadie del mundillo CP/M le prestó la más mínima atención, y el software desarrollado para el 128 fue, redondeando un poco… absolutamente ninguno. Y todo ello costó un dinero en desarrollo y le quitó parte del poco marketing que se podían permitir las eximias cuentas de Commodore al Amiga, que ya no iba muy fino en su batalla con Macs y PCs. Commodore no moriría hasta mediados de la década de los 90, pero la cosa ya no pintaba bien :-(.