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Three Types of Buffering • Based on how the temporary storage is “flushed” (=buffer를 비우는 방법에 따라 buffering 타입 다름) – Block buffering  The buffer is flushed when it receives a certain amount of data (e.g. 1KB, 16KB, 64KB, etc…)  Commonly used for large data transfers, such as file I/O => 특정 양을 받았을 때 비움 – Line buffering  The buffer is flushed when it receives a newline character(‘\n’)  Typically..

Modules (2/12 again) •Many modern operating systems implement loadable kernel modules (run time에 어떤 코드 블록을 올릴 수 있는 것= kernel module) –Uses object-oriented approach –Each core component is separate –Each talks to the others over known interfaces –Each is loadable as needed within the kernel –Linux, Solaris, etc • Overall, similar to layers but with more flexible • Similar to microkernel but no me..

Systems Calls Protecting the System • How can OS prevent user applications from harming the system? – What if an application accesses disk drive directly? – What if an application overrides interrupt handlers for keyboard? – What if an application executes the HLT instruction? Systems Calls Protecting the System • How can OS prevent user applications from harming the system? – What if an applica..

reference) https://sepang2.tistory.com/34 Linkers and Loaders 이전까지는 어셈블러에 대해 알아보았다. 어셈블러는 어셈블리어를 기계가 이해할 수 있는 기계어(object code)로 변환시키는 역할을 한다고 했다. 이제 그 다음 과정을 위해 사용되는 링커(Linker) sepang2.tistory.com Assembler Design Option •2-pass assembler scans source code twice! –First, to produce a symbol table and secondly to produce object codes. •Is this the only way to design an assembler? –Of course, NOT…..

Machine-Independent Assembler Features • There are some common assembler features that are not closely related to machine architecture – The presence or absence of such features is much more closely related to issues such as programmer convenience and software environment than it is to machine architecture • 5 features are introduced in our textbook (Chapter 2.3) Literals - 상수 값 자체를 바로 쓸 수 있도록! ..