/en/categories/learning/ Recent content in Learning on Kirin's Backspace Hugo en © {year} Kirin Sat, 27 May 2023 21:29:00 +0800 /en/_deprecated_posts/os-review/ Sat, 27 May 2023 21:29:00 +0800 /en/_deprecated_posts/os-review/ Ch6, 7 Process Synchronization What is race condition? Ch6,7 Page 4 Race condition: several processes access and manipulate the same data concurrently outcome depends on which order each access takes place. 竞态条件（race condition）：多个进程并发访问和操作统一数据并且执行结果与特定 /en/_deprecated_posts/os-note-ch5-cpu-scheduling/ Wed, 29 Mar 2023 09:50:00 +0800 /en/_deprecated_posts/os-note-ch5-cpu-scheduling/ Basic Concepts Purpose of multiprogramming: maximum CPU utilization CPU–I/O Burst Cycle Process execution consists of a cycle of CPU execution and I/O wait CPU burst followed by I/O burst CPU burst distribution is of main concern: a large number of short CPU bursts and a small number of long CPU bursts. Operation Type Load store, add store, read from file CPU burst Wait for I/O I/O burst Store increment /en/_deprecated_posts/os-note-ch4-threads/ Tue, 28 Mar 2023 21:38:00 +0800 /en/_deprecated_posts/os-note-ch4-threads/ Overview Motivation Behind Threads Multiple tasks with the application can be implemented by separate threads (Scalability, Responsiveness ) Update display Fetch data Spell checking Answer a network request Process creation is heavy-weight while thread creation is light- weight (economy) Threads run within the application/process (Resource Sharing) Can simplify code, increase efficiency Most modern applications are multithreaded Kernels are generally multithreaded Single and Multithreaded Processes Multithreaded Server Architecture Benefits Responsiveness – may allow continued execution if /en/_deprecated_posts/os-note-ch3-processes/ Mon, 27 Mar 2023 09:00:00 +0800 /en/_deprecated_posts/os-note-ch3-processes/ Process Concept Process a program in execution in memory execution must progress in sequential fashion There can be several processes for one program Consider multiple users executing the same program Memory [Process (active)] A | Mouse click or command input | Loader loads program | Disk [Program: Executable file <= Object file <= Source file (passive)] ELF Object File Format: ELF (Executable and Linkable Format , Generic name: ELF binaries) A process includes multiple parts /en/_deprecated_posts/os-note-ch2-operating-system-structures/ Sun, 26 Mar 2023 20:43:00 +0800 /en/_deprecated_posts/os-note-ch2-operating-system-structures/ Operating System Services Operating systems provide an environment that offer services to programs and users Functions to the user User interface (UI) Command-Line Interface (CLI), Graphics User Interface (GUI), touch-screen, batch processing (批处理) Program execution Load a program into memory Run a program, and then end execution. I/O operations File-system manipulation Read-write Communications Process exchange information Error detection Handle possible errors (from hardware or software) Functions for the efficient operations Resource /en/_deprecated_posts/os-note-ch1-introduction/ Sun, 26 Mar 2023 16:33:00 +0800 /en/_deprecated_posts/os-note-ch1-introduction/ Computer-System Architecture and Organization I/O Devices: except CPU and memory I/O devices and the CPU can work concurrently(同时) CPU and Memory in Computer Single processor Multiple processors Dual core Non-Uniform Memory Access System (NUMA) Device driver (software) inside the kernel knows how to talk and manage the device provides uniform interface between controller and kernel Each device controller informs CPU /en/posts/python-nlp-group-project/ Sun, 12 Dec 2021 08:50:00 +0800 /en/posts/python-nlp-group-project/ Foreword With the end of Python course(FE), the teacher also assigned us the final group assignment. It feels really bad to drag and drop a group by one person. ( However, the deadline for group assignments is December 18th. Because the course is set for beginners, Undoubtedly, it is obvious, the content of the course is not closely related to the final assignment. It is extremely difficult to require other members of my group to complete the project together.