In-depth understanding of computer system notes

Two. Hierarchy of memory

The lower-level devices in the hierarchy have a longer access time and tend to use larger blocks in order to compensate for these longer access times.

Types of Cache Misses:

Cold not hit (empty)

Conflict not hit (MOD4)

Capacity not hit

2. Cache Determines whether a cache is hit through these three ways

1) Group selection 2) row matching 3) block extraction

I. Main tasks of the linker:

1. Symbolic parsing: Associate each symbol reference in the code with a defined symbolic definition (e//can relocate the target file collection, u//the set of unresolved symbols, d//the previously defined set of symbols in the file)

2. Reposition:

2.1 Reposition section and symbol definitions merge the same section for each section defined by the input module, and for each symbol, assign a unique runtime memory address

2.2 The symbol reference in the relocation section: the linker modifies the reference to each symbol in the Code section and Data section by repositioning the entry so that they point to the correct run-time address. (Relative references and absolute references)

Two. Dynamic links and static links

Links can be done at compile time by a static compiler, or by a dynamic linker at load and run time.

When you create an executable, you statically perform some links, and then when the program loads, the process of dynamically completing the link.

Dynamically linked code and data sections without any dynamic-link libraries are actually copied to the executable, whereas the linker simply copies some relocation and symbol table information , allowing the runtime to parse references to code and data in the dynamic-link library.

Third, abnormal control flow

3.1

The most important use of traps is to provide an interface between the user program and the kernel, called a system call.

3.2

Process a passes an exception into kernel mode and then to process B so that

3.3 Process Control

Reclaim Child processes

In-depth understanding of computer system notes