CS 3733 Operating Systems

• Takes first from from free list and replaces it
• Also faults adjacent pages
• If no frames on free list, uses per-process FIFO
• Processes start with default working set of 30 pages
• NT periodically tells a valid page if if no faults occur, working set reduced by 1
• Processes with a lot of faults may get allocation increased.

• uses message passing
• server publishes visible connection-port object
• client opens handle to port and sends a connection request
• server creates a channel and returns a handle
• channel consists of pair of ports for two way communication
• accept callbacks so that they can take requests rather than replies
• three types of messages:
  • small (upto 256 bytes) - uses ports message queue for storage
  • larger - shared memory object is created and message contains pointer to memory object
  • quick LPC
    • used for Win32 subsystem
    • server ents up dedicated thread, 64 KB section object and event-pair object to notify server when client has copied a message or vice versa.

• responsible for file systems, cache, device drivers and network drivers
• converts all request to I/O request packet (IRP)
• forwards IRPs to correct drivers
• last driver sends IRP to I/O manager to complete request
• VM maps up to 1/2 of system address space to file cache
• Cache deviced up into 256 KB blocks
• each cache block can hold a view represented by a virtual address control block (VACB)
• For each open file, the cache manager has a separate VACB table

Skill: Have a basic overview of NT design