Run-Time System and Virtual Machine

Run-Time System and Virtual Machine

A run-time system consists of an execution engine, a machine-level debugger, A assembler, and related development tools).

Standard Operation Procedure (SOP): declares a proposition for demonstration and provides examples. That is, proposition-proof-example.

This topic is suitable for System Engineers.

Virtual machines must meet the following three criteria:
1) portability
Portability is the most important feature. It allows applications to work on consistent working interfaces and run on multiple platforms.
2) Simplicity
3) Performance

Symbol habits
Standard CProgramming LanguageThe habits.
The decimal number is always a number ranging from 1 ~ 9, for example, 214159
The prefix with 0x or 0x, for example, 0xa5
The octal value starts with 0, for example, 0644.
1 byte = 8 bits
1 word = 2 bytes
1 double word = 4 bytes
1 Quad word = 8 bytes
1 Paragraph = 16 bytes
1 kilobyte = 1024 bytes
1 megabyte = 1024kb
1 gigabyte = 1024 MB
1 terabyte = 1024 GB

A running-time system is an environment in which programs execute.
A run-time system provides everything a program needs in order to run.

Run-Time System: allocates memory to applications.ProgramLoad the application to the allocated memory space and execute the help program commands.
If an application calls the following operating system services through the system, the run-time system is responsible for processing these service requests.
For example, if a program wants to perform I/O operations, run-time system must provide a mechanism to communicate with the disk controller and provide read/write access.

There are several different run-time systems.

A virtual machine is a software program that acts like a computer. It fetches and executes instructions just like a normal processor.
A virtual machine also usually contains facilities to manage the path of execution and to offer an interface to services normally provided by the native operating system.

Virtual machines are defined using JVM specifications. A virtual machine is not a special software implementation, but a set of rules.

A virtual machine can be implemented in any programming language on any platform as long as it meets the specifications.

Note that all virtual machines are run-time systems, but not all run-time systems are virtual machines.