In this work I explain architecture of a 16-bit computer named Hack computer. Processor is main part of every computer and is used to fetch and execute instructions. Basic instructions are used for saving numbers in computer, reading or executing various arithmetic or logical operations. Arithmetic-logic unit is a part of a processor which executes operations with numbers. Memory unit is a part of a computer used for temporary or permanent saving of data. Input and output units communicate with computer via memory unit. Œere are two ways of writing writing programs for Hack computer: as zeros and ones (machine language) or simbolically (assembly language). If a program is wriŠen using assembler, then it must be translated to machine language in order to execute it. Œere are two types of instructions: €rst type is capable of loading and storing numbers in computer, and second type is used for reading and doing operations. All mentioned units can be connected together in order to make the Hack computer. Œis computer is working very simply: processor receives instruction from memory, executes it and, if there are outputs, saves them in memory and then sends another instruction to memory for loading next instruction