• My Pascal compiler and Polish contemporary art

      Origins


      Several years ago I wrote a Pascal compiler. The motivation was simple: as a teenager, I had learnt from my first programming textbooks that a compiler is a very sophisticated thing. This claim eventually became a challenge and required to be tested by experience.

      image
      ha.art.pl

      First, a simplistic PL/0 compiler came into being, and later an almost fully-functional Pascal compiler for MS-DOS has grown from it. My source of inspiration was the Compiler Construction book by Niklaus Wirth, the inventor of the Pascal language. I don't care if Wirth's views are now considered obsolete and have no direct connections to the IT mainstream, or if the compiler design fashion has changed. It is enough to know that his techniques are still simple, elegant, and — last but not least — bring much fun, since it is more appealing to parse a program source with a handwritten recursive descent parser and generate the machine code, rather than to call yaccs, bisons and all their descendants.

      My compiler's fate was not so trivial. It has lived two lives: the first one in my own hands, and the second in the hands of computer antiquarians from Poland.
      Read more →
    • PC Speaker To Eleven

        Known now as a «motherboard speaker», or just «beeper», PC Speaker has been introduced in 1981 along with the first personal IBM computer. Being a successor of the big serious computers for serious business, it has been designed to produce very basic system beeps, so it never really had a chance to shine bright as a music device in numerous entertainment programs of the emerging home market. Overshadowed by much more advanced sound chips of popular home game systems, quickly replaced with powerful sound cards, it mostly served as a fallback option, playing severely downgraded content of better sound hardware.

        «System Beeps» is a music album in shape of an MS-DOS program that features original music composed for PC Speaker using the same basic old techniques like ones found in classic PC games. It follows the usual retrocomputing demoscene formula — take something rusty and obsolete, and push it to eleven — and attempts to reveal the long hidden potential of this humble little sound device. You can hear it in action and form an opinion on how successful this attempt was at Bandcamp, or in the video below. The following article is an in-depth overview of the original PC Speaker capabilities and making of the project, for those who would like to know more.

        Read more →
      • Understanding the POCSAG paging protocol

          Long time ago, when a mobile phone costed about 2000$ and one minute of voice call was 50 cents, pagers were really popular. Later cellular phones became cheaper, calls and SMS prices became lower, and finally pagers mostly disappeared.


          For people, who owned a pager before, and want to know how it works, this article will be useful.
          Read more →
        • 286 and the network

          • Translation
          Author of the original post in Russian: old_gamer

          image

          I'm a ragman. I have a closet full of old hardware. From Boolean logic microchips in DIP-cases to Voodoo5. Of course, there's no practical value in all of this, but some people enjoy messing with old hardware. If you are one of them, I invite you under the cut, where I will tell you how the computer based on AMD 286 processor worked with a modern network, and what came out of it.
          Read more →