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34 lines
1.3 KiB
Markdown
34 lines
1.3 KiB
Markdown
---
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title: "21-memory-management"
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aliases:
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tags:
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- cosc204
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- lecture
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---
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# storage heirachy
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primary storage - cache and main memory
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secondaryy - hard drive
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as we move from secondary to primary:
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- access speed increases
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- access time decreases
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- cost increases
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- capacity decreases
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# process memory image and logical and physical addresses
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- a program is compiled and linked into a process image before loading into memory for execution
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- a process memory image consists of code section, data sections, lib sections, and stack sections
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- each process has its own logical memory space starting from 0 and ending at a maximum address
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- the logical address has to be translated into physical address before sending the memory request to the physical memory modules
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- the memory management unit (MMU) translated between the logical addresse and the physical addresses.
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- physical mode - progam refers directly to physical address
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- protected mode - dont allow program to use physical address directly - uses logical address
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- OS kernel creates a map from logical address to the physical address using a mapping table
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- CPUrefers to this table to map between physical and logical address
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# paging for memory translation |