ch8 - Chapter 8: Main Memory Chapter Adapted to COP4610 by...

Info iconThis preview shows pages 1–8. Sign up to view the full content.

View Full Document Right Arrow Icon
Chapter 8: Main Memory Chapter 8: Main Memory Adapted to COP4610 by Robert van Engelen
Background image of page 1

Info iconThis preview has intentionally blurred sections. Sign up to view the full version.

View Full DocumentRight Arrow Icon
8.2 Silberschatz, Galvin and Gagne ©2005 Operating System Concepts – 7 th Edition, Feb 22, 2005 Background Background Program must be brought (from disk) into memory and placed within a process for it to be run Main memory and registers are only storage CPU can access directly Register access in one CPU clock (or less) Main memory can take many cycles Cache sits between main memory and CPU registers Disk L2/L3 cache Main memory Registers L1 cache
Background image of page 2
8.3 Silberschatz, Galvin and Gagne ©2005 Operating System Concepts – 7 th Edition, Feb 22, 2005 Binding of Instructions and Data to Memory Binding of Instructions and Data to Memory Binding of instructions and data to memory addresses can happen at Compile time : If memory location known a priori, absolute code can be generated; but must recompile code if starting location changes Load time : Must generate relocatable code if memory location is not known at compile time Execution time : Binding delayed until run time if the process can be moved during its execution from one memory segment to another Need hardware support for address maps (e.g., base and limit registers)
Background image of page 3

Info iconThis preview has intentionally blurred sections. Sign up to view the full version.

View Full DocumentRight Arrow Icon
8.4 Silberschatz, Galvin and Gagne ©2005 Operating System Concepts – 7 th Edition, Feb 22, 2005 Logical vs. Physical Address Space Logical vs. Physical Address Space The concept of a logical address space that is bound to a separate physical address space is central to proper memory management Logical address – generated by the CPU; also referred to as virtual address Physical address – address seen by the memory unit Logical and physical addresses are the same in compile- time and load-time address-binding schemes Logical (virtual) and physical addresses differ in execution-time address-binding scheme
Background image of page 4
8.5 Silberschatz, Galvin and Gagne ©2005 Operating System Concepts – 7 th Edition, Feb 22, 2005 Memory-Management Unit ( Memory-Management Unit ( MMU MMU ) ) Hardware device that maps virtual to physical address In MMU scheme, the value in the relocation register is added to every address generated by a user process at the time it is sent to memory The user program deals with logical addresses; it never sees the real physical addresses
Background image of page 5

Info iconThis preview has intentionally blurred sections. Sign up to view the full version.

View Full DocumentRight Arrow Icon
8.6 Silberschatz, Galvin and Gagne ©2005 Operating System Concepts – 7 th Edition, Feb 22, 2005 Dynamic Loading Dynamic Loading Routine is not loaded until it is called Better memory-space utilization Unused routine is never loaded Useful when large amounts of code are needed to handle infrequently occurring cases No special support from the operating system is required Implemented through program design
Background image of page 6
8.7 Silberschatz, Galvin and Gagne ©2005 Operating System Concepts – 7 th Edition, Feb 22, 2005 Dynamic Linking Dynamic Linking Linking postponed until execution time Small piece of code, called stub
Background image of page 7

Info iconThis preview has intentionally blurred sections. Sign up to view the full version.

View Full DocumentRight Arrow Icon
Image of page 8
This is the end of the preview. Sign up to access the rest of the document.

This note was uploaded on 10/11/2011 for the course COP 4610 taught by Professor Robertengelen during the Spring '11 term at FSU.

Page1 / 51

ch8 - Chapter 8: Main Memory Chapter Adapted to COP4610 by...

This preview shows document pages 1 - 8. Sign up to view the full document.

View Full Document Right Arrow Icon
Ask a homework question - tutors are online