★ Process space ￥ 斗 ★★ o Also called Address space o All the data the process as it runs o Passive(acted upon by the process o Play analogy: all the objects on the stage in a play
11 Process Space Also called Address Space All the data the process uses as it runs Passive (acted upon by the process) Play analogy: – all the objects on the stage in a play
★ Process space ￥ 斗 ★★ o Is the unit of state partitioning Eachprocessocaupiesa different state of the computer s Main topic How multiple processesspaces can sharea singe physical memory efficiently and safely
12 Process Space Is the unit of state partitioning – Each process occupies a different state of the computer Main topic: – How multiple processes spaces can share a single physical memory efficiently and safely
★ Manage Process &l Space ￥ 斗 ★★ o Who manages process space? Theoperatingsystems s How does os achieve it? By maintain infomation bout processes i.e. use processtables
13 Manage Process & Space Who manages process & space? – The operating systems How does OS achieve it? – By maintain information about processes – i.e. use process tables
★ Fieldsof a process table ￥ 斗 ★★ o Registers, Program counter, Statusword o Stack pointer, Priority, Process ID o Parent group, Process group, Signals s Time when process started o CPU time used, children' s CPU time, etc. 14
14 Fields of A Process Table Registers, Program counter, Status word Stack pointer, Priority, Process ID Parent group, Process group, Signals Time when process started CPU time used, Children’s CPU time, etc
★ Problemswith process ￥ 斗 ★★ o While supportingmultiprogammingon shared hardware o Itself is single threaded i. e a process candoonly one thingata time blocking call rendersentire processunrunnable 15
15 Problems with Process While supporting multiprogramming on shared hardware Itself is single threaded! – i.e. a process can do only one thing at a time – blocking call renders entire process unrunnable