What is distributed system development?
In a distributed system, a set of independent computers presents a unified whole to the user, as if it were a system. The system has a variety of general physical and logical resources, which can dynamically allocate tasks, and the scattered physical and logical resources realize information exchange through computer networks. There is a distributed operating system in the system that manages computer resources in a global manner. Often, a distributed system has only one model or paradigm to the user. On top of the operating system, there is a layer of software middleware (middleware) responsible for implementing this model. A well-known example of a distributed system is the World Wide Web, where everything looks like a document (Web page).
In a computer network, this uniformity, the model, and the software within it do not exist. What users see are actual machines, and the computer network doesn't make these machines appear to be unified. If these machines have different hardware or different operating systems, then these differences are completely visible to the user. If a user wishes to run a program on a remote machine, he must log on to the remote machine and run the program on that machine.
The common point between distributed systems and computer network systems is that most distributed systems are built on computer networks, so the physical structure of distributed systems and computer networks is basically the same.
The difference between them is: the design ideas of distributed operating systems and network operating systems are different, which determines that they are also different in structure, working method and function. The network operating system requires that network users must first understand network resources when using network resources. Network users must know the functions and configurations of each computer in the network, software resources, network file structure, etc. If the user wants to read a shared file in the network , the user must know which directory on which computer the file is placed; the distributed operating system manages system resources in a global manner, it can arbitrarily schedule network resources for users, and the scheduling process is "transparent". When a user submits a job, the distributed operating system can select the most suitable processor in the system as required, submit the user's job to the processing program, and transmit the result to the user after the processor completes the job. During this process, the user does not realize that there are multiple processors, and the system acts as a single processor.
Distributed Systems Development Scheduling Techniques: Getting Started