Computer Metanoia

Different Addressing Modes ~By Anonyo Sanyal The operation field of an instruction specifies the operation to be performed. This operation must be executed on some data stored in computer registers or memory words. The way the operands are chosen during program execution is dependent on the addressing mode of the instruction. The addressing mode specifies a rule for interpreting or modifying the address field of the instruction before the operand is actually referenced. Computers use addressing mode techniques for the purpose of accommodating one or both of the following provisions: 1. To give programming versatility to the user by providing such facilities as pointers to memory, counters for loop control, indexing of data, and program relocation. 2. To reduce the number of bits in the addressing field of the instruction. In simpler words, it can be compared to the addressing of a particular location on earth. Just like we have different ways to reach a particular addres

Difference between JRE, JVM, and JDK By ANONYO SANYAL Now, this article lays a foundation to learn the internals of a JVM. To do that first we need to understand JRE, JVM and JDK and their differences. Once you are done click here to learn the internal details of JVM JVM:- Firstly JVM stands for Java Virtual Machine.  Secondly, JVM is an abstract machine i.e. it doesn't exist in reality. It is just an abstract concept. It is the detailed description of the design and materials which provides a runtime environment to run the java bytecode .  Funny fact, we all know java is a platform independent programming language. But do you know that JVM, JRE, and JDK are platform dependent? The reason is pretty clear. we said that JVM gives a specification (detailed description of the design and materials) for the runtime environment to run the java bytecode. But the specification changes from one Operating System to another. Now to make Java a platform-independent programmin