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ELF II

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Manufacturer
  
Netronics

Operating system
  
Monitor ROM

Type
  
Hobbyist computer

CPU
  
8 bit RCA 1802

ELF II

Release date
  
1978; 39 years ago (1978)

Memory
  
256 Bytes to 64KB via 4KB or 16KB memory expansion cards

The Netronics ELF II was an early microcomputer trainer kit featuring the RCA 1802 microprocessor, 256 bytes of RAM, DMA-based bitmap graphics, hexadecimal keypad, two digit hexadecimal LED display, a single "Q" LED, and 5 expansion slots. The system was developed and sold by Netronics Research and Development Limited in New Milford, CT, USA.

Contents

Hardware

Available hardware accessories included:

  • The "Giant Board" (ROM monitor, serial and parallel I/O, Cassette interface)
  • 4KB and 16KB (static) RAM boards
  • ASCII Keyboard
  • Video display card (monochrome text)
  • Low resolution color graphics board
  • "Full BASIC" board with BASIC preloaded in ROM chips
  • EPROM burner board
  • External Power Supply
  • Attractive, heavy duty metal cases for the CPU, keyboard, and power supply

    • Software

    Available software included:

  • Tiny BASIC (integer BASIC)
  • Text Editor
  • Full BASIC (floating point BASIC using Reverse Polish Notation)

    • Notable Innovations

  • Unlike similar "bare circuit card" trainer/experimenter computers of the day, the ELF II could be easily expanded thanks to its built-in bus.
  • The video card is mounted underneath the keyboard inside the metal case. This allows it to be used as a standalone computer terminal if needed.
  • The Elf II used a simple and low-cost math coprocessor. The "Full BASIC" ROM card contained an RPN calculator chip. As a result, floating point operations were an order of magnitude faster than what was possible in software. However, the BASIC syntax for math was non-standard as it used postfix RPN (see code example below). Historically, this was also the heyday of Hewlett Packard calculators, so it was a fair bet that any technically minded person willing to assemble a computer either already knew RPN or could easily learn it and adapt.

    • In the code above, the "#" symbol is equivalent to the "Enter" key on a RPN calculator.

    The Name

    The ELF part of the name came from an earlier machine called the "COSMAC ELF", published as a construction project in Popular Electronics magazine. Improvements on its predecessor included an etched PCB, a hexadecimal keypad instead of toggle switches for program entry, the CDP1861 Pixie-graphics chip, and the 5 slot 86-line bus for expansion cards.

    References

    ELF II Wikipedia
    (Text) CC BY-SA


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