Process control information Process Control Bbc Entry point to program Branch Program instruction Increas ing address values Reference to data Data Current top of stack Stack Figure 7.1 Addressing Requirements for a Process
MEMORY MANAGEMENT
Memory Protection(p291) Each process should be protected against unwanted interference(访问) by other processes. All memory references generated by a process must be checked(检查) at run time The memory protection requirement is satisfied(C]) by the processor (hardware) rather than the os (software) MEMORY MANAGEMENT
MEMORY MANAGEMENT Memory Protection (p291) • Each process should be protected against unwanted interference（访问）by other processes. • All memory references generated by a process must be checked（检查） at run time. • The memory protection requirement is satisfied（完成） by the processor (hardware) rather than the OS (software)
Memory Sharing(共享p291) Share data and code for save(节省) the memory The memory-management system must allow controlled access to shared areas of memory without compromising(影响) essential protection MEMORY MANAGEMENT
MEMORY MANAGEMENT Memory Sharing（共享p291） • Share data and code for save(节省) the memory. • The memory-management system must allow controlled access to shared areas of memory without compromising（影响） essential protection
Logical Organization(p291) OS should deal with programs in the form of modules(模块) Modules can be written and compiled independently. Different degrees of protection can be given to different modules It is easy to implement share. E. g segmentation(分段管理) MEMORY MANAGEMENT
MEMORY MANAGEMENT Logical Organization（p291） • OS should deal with programs in the form of modules(模块) • Modules can be written and compiled independently. • Different degrees of protection can be given to different modules. • It is easy to implement share. • E.g. segmentation(分段管理)
Physical Organization(p292) · Computer memory is organized(组织) into at least two levels, referred to as main memory and secondary memory. Swapping the modules in and out as needed The programmer does not know how much space will be available or where that space will be MEMORY MANAGEMENT
MEMORY MANAGEMENT Physical Organization(p292) • Computer memory is organized（组织） into at least two levels, referred to as main memory and secondary memory. • Swapping the modules in and out as needed. • The programmer does not know how much space will be available or where that space will be