Paging, sgementation and memory

• Memory management


  1. Paging

  2. Segmentation

  3. Virtual memory
• Main memory


  • Loads operating system
  • Loads programs A, B, C, D
  • Program C closed, memory released
  • Program E arrives but doesn't fit
• Paging


  Memory divided into fixed-size pages, programs split to fit these pages
• Segmentation


  Memory divided into variable-size logical sections of programs, programs split to fit these sections
• Similarities and differences between paging and segmentation


  • Pause video to take notes
• Main memory becomes full


  Virtual memory used
• Virtual memory


  Storing programs and data on hard disk when not in use, swapping with RAM as needed
• Virtual memory gives the impression of more memory than actually available
• Handling running out of memory

  • Swapping programs between RAM and virtual memory on hard disk
  • Slows down computer performance
• Virtual addresses are used to access data stored in physical memory or on disk.
• Paging involves dividing the virtual address into two parts - page number (page frame) and offset within the page.
• The virtual address space is the total amount of memory that can be accessed by an application.
• The operating system manages the mapping of virtual addresses to physical locations using page tables.