ELF II

ELF II

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Manufacturer	Netronics
Type	Hobbyist computer
Release date	1978 (1978)
Operating system	Monitor ROM
CPU	8 bit RCA 1802 @ 1.76MHz
Memory	256B - 64KB
Storage	Cassette Tape

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.

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 notation. 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 already knew RPN.

10 REM This program will print the number 30
20 A=10,B=20
30 C=A#B+
40 PRINT C
50 END

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.

See also

• COSMAC ELF
• RCA COSMAC VIP
• Quest SuperELF
• RCA 1802 microprocessor
• Early Microcomputers
• Competing 6502 microprocessor based trainers KIM-1 and Rockwell AIM-65
• 8080 Based machines: MITS Altair 8800 and IMSAI 8080
• RCA Studio II