= = = WHEATSYSTEM = = =

WheatSystem is an operating system by Jack Eisenmann.

Design specification:

• WheatSystem Architecture
• WheatBytecode Documentation
• WheatSystem Functions
• Specification Repository

Software utilities:

• WheatBytecode Assembler
• WheatSystem C Implementation
• WheatSystem Integration Tests

Version 1.0.0 of the WheatSystem specification and the C implementation are complete.

Computers which run WheatSystem:

• WheatBox 55A1

Please see this video for an overview of WheatSystem and WheatBox 55A1.

WHEATBOX MODEL NUMBERS

Each computer intended to run WheatSystem is named "WheatBox" followed by a model number. The model number consists of the following components:

(ramSize)(formFactor)(processorType)(variation)

(ramSize) is an integer which describes the amount of RAM in the computer:

• When (ramSize) = 1, RAM size is under 4 KB
• When (ramSize) > 1, RAM size is at least 2^(ramSize) KB

(formFactor) is a digit which describes the I/O and power supply of the computer:

• 0 = Has no built-in keyboard or display
• 5 = Has built-in keyboard and display, and does not require external wired power
• 8 = Has built-in keyboard and display, but requires external wired power

(processorType) is a letter which describes the technology for executing machine code:

• T = Discrete transistors
• L = Discrete logic chips
• W = 6502 processor
• Z = Z80 processor
• A = AVR microcontroller
• P = PIC microcontroller
• R = ARM processor
• N = Intel processor

(variation) is an integer which describes the iteration of computer design. This number begins at 1 for a given permutation of (ramSize)(formFactor)(processorType), and increases by 1 for each additional design which has the same permutation of (ramSize)(formFactor)(processorType). Different variations may have different button layouts, types of displays, processor models, and so forth.

Example WheatBox model numbers:

• 55A1 = First design with AVR microcontroller, 32 KB of RAM, built-in keyboard + display, and not requiring external wired power
• 60P2 = Second design with PIC microcontroller, 64 KB of RAM, and no built in keyboard/display

WHEATSYSTEM MOTIVATION

While designing and implementing BreadSystem, I realized that the operating system was rather complex. I was worried that the firmware would be too big for simpler hardware, such as the venerable ATMega328, or a processor with 16-bit address space and no bank switching. These are hardware platforms I enjoy using, and I expected that BreadSystem would leave them in the dust.

WheatSystem uses many of the same design principles of BreadSystem, but simplifies them substantially. It has a bytecode with fewer instructions, permission system with less granularity, and file system lacking directory support. However, it still provides a unified heap and interprocess communication through exposed functions. I think that WheatSystem will be fun to play with, and I look forward to incorporating it into future hardware projects.