En esta práctica se diseña e implementa un sistema de control de acceso remoto codificado implementado utilizando lógica discreta. El control de acceso se realiza mediante el envío simulado de tonos (según un esquema parecido a DTMF) que permiten representar los cuatro dígitos de tres bits de la clave de acceso. Un autómata permite automatizar el envío del código. Por otro lado, el sistema indica los dígitos introducidos mediante realimentación auditiva.
La memoria está disponible en los siguientes formatos:
Código fuente LaTeX de la memoria , junto con los archivos postscript de gráficas y esquemas (.tgz) v1.1
La memoria en formato postscript comprimido (.ps.gz) v1.0
La memoria en formato dvi comprimido (.dvi.gz) (no contiene las gráficas) v1.0
Los datos y scripts necesarios para generar las gráficas (.tgz) v1.0
Los archivos postscript de los esquemas circuitales , editables mediante xcircuit (.tgz) v1.0
Son creadas a partir de ficheros de datos mediante el programa libre GNU gnuplot, disponible bajo los términos de la licencia GPL. El proceso está automatizado mediante scripts y un fichero Makefile. Para evitar complicaciones innecesarias se incluyen los ficheros postscript resultantes.
:blinkenlights: /blink'*n-li:tz/ /n./ Front-panel diagnostic lights on a computer, esp. a {dinosaur}. Derives from the last word of the famous blackletter-Gothic sign in mangled pseudo-German that once graced about half the computer rooms in the English-speaking world. One version ran in its entirety as follows: ACHTUNG! ALLES LOOKENSPEEPERS! Das computermachine ist nicht fuer gefingerpoken und mittengrabben. Ist easy schnappen der springenwerk, blowenfusen und poppencorken mit spitzensparken. Ist nicht fuer gewerken bei das dumpkopfen. Das rubbernecken sichtseeren keepen das cotten-pickenen hans in das pockets muss; relaxen und watchen das blinkenlichten. This silliness dates back at least as far as 1959 at Stanford University and had already gone international by the early 1960s, when it was reported at London University's ATLAS computing site. There are several variants of it in circulation, some of which actually do end with the word `blinkenlights'. In an amusing example of turnabout-is-fair-play, German hackers have developed their own versions of the blinkenlights poster in fractured English, one of which is reproduced here: ATTENTION This room is fullfilled mit special electronische equippment. Fingergrabbing and pressing the cnoeppkes from the computers is allowed for die experts only! So all the "lefthanders" stay away and do not disturben the brainstorming von here working intelligencies. Otherwise you will be out thrown and kicked anderswhere! Also: please keep still and only watchen astaunished the blinkenlights. See also {geef}. Old-time hackers sometimes get nostalgic for blinkenlights because they were so much more fun to look at than a blank panel. Sadly, very few computers still have them (the three LEDs on a PC keyboard certainly don't count). The obvious reasons (cost of wiring, cost of front-panel cutouts, almost nobody needs or wants to interpret machine-register states on the fly anymore) are only part of the story. Another part of it is that radio-frequency leakage from the lamp wiring was beginning to be a problem as far back as transistor machines. But the most fundamental fact is that there are very few signals slow enough to blink an LED these days! With slow CPUs, you could watch the bus register or instruction counter tick, but at 33/66/150MHz it's all a blur. |