ProcessA process is an instance of an application. Each process has its own independent execution context and resources, such as a virtual address space. Practical operating systems provide the execution context as a separate concept called a "thread". For simplicity, in this book we'll treat each process as having a single thread.   Process control block The following process structure defines ..

The Process StructureIn addition to the references to the substructures, the process entry shown in Figure 4.1 contains the following categories of information: • Process identification: the PID and the parent PID • Signal state: signals pending delivery and summary of signal actions• Tracing: process tracing information• Timers: real-time timer and CPU-utilization counters  The process substruc..

4.2 Process StateEvery process in the system is assigned a unique identifier termed the process identifier (PID). PIDs are the common mechanism used by applications and by the kernel to reference processes. PIDs are used by applications when the latter send a signal to a process and when receiving the exit status from a deceased process. Two PIDs are of special importance to each process: the PI..

Part II: ProcessesChapter 4.1 Introduction to Process ManagementA process is a program in execution. (프로세스의 정의. 정확하게 따지자면, 프로그램과는 구분된다.)A process has an address space containing a mapping of its program’s object code and global variables. It also has a set of kernel resources that it can name and on which it can operate using system calls. These resources include its credentials, signal state, a..

Architecture (11/4 가즈윌)  View controller View 라는 스레드가 한없이 돈다OS에서는 Process안에 수많은 thread가 돈다 아키텍쳐란?하나의 view만 본다면 여러 컴포넌트의 모임이지만,동적인 (런타임) 측면에서는 Process, App 하나를 의미메모리에서 죽지 않는 영역 동적이고 정적인 측면을 다 보아야 한다.MVC: Logical architecture Runtime architectureProcess, Thread 실제로 런타임에서 바라보는 구조 (OS가 인식하는 구조)두 개의 앱이 데이터를 공유해야 한다면?프로세스: 데이터를 정의하지 않는다.그럼? 세션 메세지 통신 등등의 방법이 있다. Conceptual architecture 쓰임새에 맞게 붙인 이름들어..

DispatchQueue.main() -> main 스레드, UI 관련 작업은 반드시 메인 스레드에서만! DispatchQueue.global() -> 이외의 다양한 처리들은 백그라운드에서 == global 이때, UI 관련 작업은 main에서! 따라서 global 내부에서, UI 코드만 main으로 감싼다. 백그라운드에서 돌리면서, 해당 작업은 main으로 가져가는 것 이제 왜 디스패치 큐 코드를 저렇게 쓰는지 이해가 가네 ;;