SOFTWARE ARCHITECTURE

Transcription

1 1 SOFTWARE ARCHITECTURE Tatsuya Hagino Slide URL

2 2 Lecture Slide System Please access to: Select: Software Architecture (2018) CNS Login Name CNS Password Select Lecture

3 3 Syllabus 1. Operating System 2. File System 3. Shell 4. Text Formatting 5. C Compiler 6. LISP Interpreter 7. Java Virtual Machine 8. Mid-tem Exam 9. Network System 10. Domain Name System 11. TELNET and Electric Mail 12. Distributed File System 13. World Wide Web 14. Window and Database Management System 15. Final Exam

4 4 Software Layer Application Library Middleware Operating System BIOS Device Driver Hardware

5 5 Application Applications = User programs Most of the programs users write are applications. Applications may be divided into: System applications Backup maintenance Language processing Compiler Interpreter Text, graphics, image and video processing Editors Network applications mail client Web browser Scientific applications numerical analysis simulation

6 Library Library collection of functions and procedures not a standalone software embedded into another software Some libraries Filesystem library Mathematical library Statistic library String library Software own program own library imported library 6 source code compiler object code Static vs Dynamic Link Library Static: linked at compile time Dynamic: linked at run time Shared Library The same library is shared among different programs. library linker load module Application 1 Application 2 Application 3 library library library shared

7 7 SOFTWARE ARCHITECTURE 1. OPERATING SYSTEM Tatsuya Hagino Slide URL

8 8 Operating System Usually called OS Fundamental Software Most PC needs one Control all the programs running on the computer Manage resources on the computer Provide various services to programs Enhance functions to the hardware and provide a virtual machine to each program Popular OS Windows: 95, 98, Me, NT, XP, Vista, 7, 8, 8.1, 10 Mac OS: 9, X UNIX: Linux, FreeBSD, NetBSD, OpenBSD, Solaris Other OS Mobile Phone: ios, Android, Windows phone Realtime System: itron, VxWorks

9 9 Role of Operating System Arbitration of hardware usage conflict Separation of programs Multi-programming Memory management File system Network system Communication among programs

10 10 Hardware Arbitration Two applications cannot control the same hardware (e.g. keyboard, mouse, printer, etc.). Arbitration by OS Applications cannot control hardware resource directly. Hardware is controlled via OS. Application A Application B Operating System Hardware H

11 11 Separation of Programs Programs can run independently. Each program has its own memory space. Each memory space is protected (i.e. cannot be referenced or altered by other programs). PC memory program A program B memory memory MMU program A resource resource MMU program B

12 12 Multi-Programming Multiple programs can run at the same time. Number of programs which can be run at once is not limited by the number of CPU cores. CPU time is assigned to programs. Process scheduling Priority control program A program B program C program D Time sharing execute A scheduler execute B CPU core 1 CPU core 2 execute C

13 13 Memory Management Allocate memory for programs Memory is divided into pages. Collect unused pages. Provide virtual memory Pages not used frequently are paged out to the external storage. Pages are paged in when necessary. Programs do not need to worry about the hardware memory size. (vs. Memory Overlay used for game software) Demand paging Program and data are loaded into memory when they are referenced at first time. Memory Space disk currently used swap program demand paging page out page in unused memory

14 14 File System Share disk drive with applications disk Create a file system on a disk file file folder Efficient buffering folder file file Popular File System FAT (Fast Allocation Table) NTFS (NT File System) HFS (Hierarchical File System) UFS (UNIX File System) LFS (Log File System)

15 15 Network System Process network packets send (programs to network) receive (network to programs) TCP/IP control fragmentation resend ordering window control Network Program A send OS Network Program B recieve Network packet packet

16 16 Communication among Programs Send data from one program to another Pipe Shared Memory Semaphore Lock Pipe Program A Program B Program A Program B shared memory

17 17 Operating System Structure Application Operating System System call processing File System Process Management Network Management Memory Management Bootstrap Scheduler Device Management Hardware

18 18 Summary Operating System Hardware Arbitration Separation of Programs Multi-Programming Memory Management File system Network system Communication among Programs