Y is called an inverter because the output is always the inverse of the input.
a) The Brookshear Machine is an easy computer reproduction with 256 bytes of memory, a CPU, registers, an Arithmetic Logic Unit and a plain language to program it in. The machine is made up of sixteen registers that have been numbered using the hexadecimal format i.e. 0x to Fx. Every register contains one byte, equivalent to eight bits. In the memory, there are 256 cells that have been numbered from 00x to FFx, where each cells seizes one byte. Every instruction written in the language is coded in two bytes. The initial half-byte that is represented by the first hex digit has the opcode.
b) I suggest the Java Virtual Machine instructions. To put into operation the Java virtual machine in the approved manner, one needs only to be able to read the class file format and be able to appropriately perform the operations specified in it. The compiled code to be performed by the Java virtual machine is signified using an independent hardware- and operating system-binary format, characteristically, though not a must, stocked up in a file, referred to as the class file format. This file format accurately describes the representation of a class or interface, together with particulars such as byte ordering that may be assumed in a platform-specific object file format.