otro blog más

Etiqueta: IBM PC

  • Byte, mayo del 85

    Seguimos leyendo la revista Byte, pero cuarenta años tarde (todas las entradas disponibles en la etiqueta Byte). Si queréis pasar de mis extractos y acudir a la fuente, tenéis todo el histórico en archive.org y el número del mes aquí.

    Este mes la cosa sera (relativamente breve). La portada, no especialmente destacable:

    Portada de la revista Byte de abril de 1985, dedicada al PC Unix de AT&T

    De las noticias, me quedo con un breve. ¿Sabíais que este mes se cumplen cuarenta años del anuncio de Excel? ¿Sabíais que Microsoft lo lanzó inicialmente para el Mac? Pues sí…

    Integrated Software for Macintosh Microsoft's first integrated package. Excel for the Macintosh, has spreadsheet and graphics capabilities, a spreadsheet oriented database, and a macro facility for storing and recalling commonly used keystrokes. It supports the AppleTalk network and provides two-way file compatibility with Multiplan and Chart for the Macintosh, Lotus 1-2-3 for the IBM PC. and applications that support Microsoft's SYLK format. The Excel spreadsheet provides you with a 256 column by 16.384-row work area. You can view and reference multiple spreadsheets, consolidate worksheets, enter multiple variable problems or situations, and vary the borders, number formats, and font styles and size. You can assign names to cell references, numbers, and mathematical expressions and call four windows into a worksheet. You can produce instant "what if' graphics with Excels charting abilities, which are functionally identical to Microsoft's Chart for the Mac. Excel files can be read directly into Chart, and Excel can read Chart files When you alter numbers in a spreadsheet window, charts in separate windows are instantly updated. For data comparisons, you can open more than one chart window for the same or different data. The charting facility also has 42 predesigned charts, the ability to relocate objects on screen, and your choice of font, range, scale, and patterns. The database is an ancillary function of Excels spreadsheet. With it, you can sort, extract, and display information in a variety of ways. The database lacks form- and report-design capabilities: however. Excels formatting capabilities let you create reports. It does let you remove data for analysis in a different section of your work area. Excels suggested retail price is $395. It requires 512K bytes of memory and will work with the Macintosh XL.

    ¿Se fiaba mucho Microsoft del éxito de Excel? Pues no sé, pero unas páginas más adelante la empresa anunciaba su solución de hoja de cálculo para el Mac:

    Anuncio de Microsoft de su hoja de cálculo para el Mac, Multiplan, más Microsoft Chart para hacer gráficas. Se hace eco de que Multiplan utiliza todas las características amigables del Mac. También anuncian que están disponibles para el Mac Word, File y BASIC.
    ¿Créiais que lo del caos de productos de las grandes tecnológicas era cosa de ahora? Pues hace cuarenta años Microsoft hacía publicidad de su hoja de cáculo Multiplan para Mac mientras anunciaba el lanzamiento de Excel para la misma plataforma…

    Y en la lista de productos tenemos nada más y nada menos que el PC AT de IBM, con su 80286 y sus 256 KBs de RAM en el modelo básico (apenas cuatro mil dólares de la época):

    IBM PC AT The PC gets down to business The IBM PC AT comes in two basic configurations. The basic model ($3995) comes with 256K bytes of RAM (random-access read/write memory), one of IBM's new high-capacity 1.2-megabyte disk drives, and a combination floppy disk/hard-disk controller card. Available for an additional $1800, the enhanced model adds 256K bytes of memory, a 20-megabyte hard-disk drive, and a serial/parallel interface adapter (see photo 1). Both systems are based on Intel's 80286 processor and have eight I/O (input/output) expansion slots and a battery-backed clock/calendar. The AT comes with IBM's usual voluminous documentation. It includes a setup guide, an operations guide, and a BASIC manual, all in IBM's standard boxed looseleaf format. An unwelcome addition is a variety of small pamphlets packed in each box. While these are intended to be helpful quick guides, they are easy to misplace and might confuse as much as inform. By the way, the BASIC manual is now complete. You don't have to send in a coupon and replace pages to get up-to-date documentation. Power Supply and Keyboard The power supply is 190 watts, as opposed to the 63 watts in the PC and 130 watts in the XT. This much power is needed. The PC is underpowered, causing many users to have hard-to-trace problems when adding to their systems. The XT's supply is much better but would be inadequate for the AT's two hard-disk drives. Since what goes in as electricity always comes out as heat, IBM has incorporated an innovative variablespeed fan that runs faster (and louder) as the internal temperature rises. Since my system was lightly loaded, the noise level never became obtrusive. A notable addition to the AT is a line-voltage select switch that lets it run on European 220-volt power. The AT's keyboard and interface are more sophisticated than those on the PC and they are not compatible. You cannot use an AT keyboard on a PC. A single-chip microcomputer on the system board manages the keyboard and related functions. Any PC software that goes directly to the keyboard interface hardware, some key-translation programs, and many games will not work on the AT. The keyboard layout is similar to that used on an IBM Selectric typewriter (see photo 2). The Shift, Control, Enter, and backspace keys have all been enlarged. Some of the less frequently used keys, such as backslash, grave accent. Print Screen, and Escape, have been moved to peripheral portions of the keyboard. Three status lights have been added to the Caps Lock, Scroll Lock, and Num Lock keys— this is a welcome feature. The only new key, Sys Req, causes the keyboard handling software that's in ROM (read-only memory) to generate a software interrupt whenever the key is pressed or released. This lets the user signal the operating system for attention. PC-DOS currently ignores Sys Req. To go with its international power supply. IBM provides six different versions of the AT's keyboard for foreign languages. The layout and internal scan codes are all identical, but some of the key legends are different to permit use of symbols peculiar to specific languages. The standard display adapters can display these characters, and DOS 3.0 has a set of utilities to adapt itself to the specific keyboard type. On the output side, the AT uses the standard PC display cards and so is completely compatible. Graphics generation is much faster than it is on the PC. Much has been said about the inclusion of a key switch that disables the keyboard and locks the cover in place. It seems to me that this feature is of limited usefulness. You would have to secure the entire system and external wiring to prevent someone with malicious intent from interfering with a running program. A program can test the state...

    Por cierto… ¿lo de la compatibilidad de los PCs? El AT venía con un teclado nuevo, y el software para los PCs anteriores de IBM que accedía directamente a sus teclados (juegos, por ejemplo)… no funcionaba en el AT. El paso del 8086 al 286, para sorpresa de nadie, también daba sus propios problemas.

    El AT, por cierto, era el primero en poder usar los novísimos discos de alta densidad, con sus casi infinitos 1,2 megabytes (hablamos de discos de 5¼ pulgadas, claro), a 500 kilobits por segundo. Sorpresa: las unidades de disco también suponían un problema de compatibilidad: si escribías a un disco de doble densidad, este no necesariamente sería legible en otros PCs. ¿Sistemas operativos? PC DOS 3.0 (no, no MS DOS) o el Concurrent DOS de Digital Research.

    Y de los anuncios, me quedo con el SORD IS-11C. ¿No os provoca una cierta ansiedad la bisagra de la pantalla?

    Anuncio del IS-11C de Sord Compuetr. Se trata de un sistema de procesador de textos y correo elctrónico portátil programable en BASIC. La bisgra que soporta la pantalla es de menos de la mitad del ancho de dicha pantalla.

    Dice la Wikipedia que llevaba un Z80 y que la resolución de la pantalla era de 256 × 64. No habla del peso ni de la batería (algo me dice que solo funcionaba enchufado a la corriente).

    Y con esto me paso a la sección de programación, donde encontramos, primero…

    0.8660254 ≈ √3/2 An algorithm that converts decimals to fractions

    Si hoy en día incluimos en una revista un programa para convertir números decimales a fracciones con la capacidad de reconocer al menos unas cuantas raíces cuadradas (el programa reconocía las raíces de 2 , 3 y 5, y π y π2), explotan cráneos (el autor, por más inri, era un estudiante de medicina de Estocolmo). Y por si esto no fuese suficiente…

    Computing Pi Using infinite series to compute mathematical functions

    (El programa usa la serie de Taylor de la arcotangente y da quince cifras de π, más que suficientes para básicamente cualquier cálculo práctico.)

    En fin. Volvemos, con un poco de suerte, el mes que viene. Si queréis anticipar el «futuro», podéis hacer trampa aquí.