Cmpt 300 Final Exam 3

Front 1

5 major activities of an operating system regards to process management are:

Back 1

1. the creation and deletion of both user and system processes

2. the suspension and resumption of processes

3. provision of mechanisms for process synchronization

4. provision of mechanisms for process communication

5. provision of mechanisms for deadlock handling

Front 2

3 major activities of an operating system in regards to memory management

Back 2

1. keep track which part of memory is currently being used by whom

2. decide which processes are to be loaded into memory when space becomes available

3. allocate and deallocate memory space as needed

Front 3

what is memory management

Back 3

1. the functionality of an operating system which handles or manages primary memory and moved processes back and forth between main memory and disk during execution

2. keeps track of every memory location regardless of whether is occupied or free

3. checks how much memory to allocate to a process

4. decides which process will get memory at what time

5. tracks whenever some memory becomes free and updates the status

Front 4

what is DRAM?

Back 4

dynamic random access memory.

stores each bit of data in a separate capacitor within an integrated circuit.

capacitor either charged or discharged. 0 or 1. but the charge will slowly leak so it has to be recharged. because of this recharge requirement it is DRAM as opposed to SRAM

Front 5

what is the primary goal of memory management?

Back 5

to provide efficient methods of allocating memory to programs and deallocating it for reuse when no longer needed

Front 6

how do we accomplish memory management?

Back 6

1. utilize memory hierarchy

- small amounts of fast, expensive memory

- Some medium speed MED price

- lots of slow cheap non volatile disk storage

2. memory manager handles memory hierarchy

- allocated scarce resource amount competing requests to maximize utilization and system throughput

- offers conveiniet abstraction for programming

-provides isolation between processes

Front 7

what is memory abstraction

Back 7

HW and OS memory manager give the user the illusion that memory is a single contiguous entity

Front 8

to allow several programs to co-exist in memory we need

Back 8

1. protection

2. relocation

3. sharing

4. logical organization

5. physical organization

Front 9

Define address space

Back 9

set of address that a process can use to address memory

Front 10

what is protection ?

Back 10

1. processes need to aquire permission to reference memory locations for reading or writing purposes

2. memory references generated by a process must be checked at run time

Front 11

Define relocation

Back 11

1. active processes need to be able to be swapped in and out of main memory in order to maximize processor utilization

2. if it needs to be swapped to the same place it would be limiting that's why we need to have relocation

Front 12

Sharing

Back 12

advantageous to allow each process to the same copy of the program rather than have their own separate copies

- memory management must allow controlled access to share areas of memory withoutbcompromising protection

Front 13

Logical Organization

Back 13

program = code +data =modules

The modules must be organized in that logical address space

Front 14

Physical Organization

Back 14

manage the different modules to give illusion of the logical organization

Front 15

Define address space

Back 15

the amount of memory allocated for all possible available for a process or physical computational entity

Front 16

Operating system takes care of mapping the logical addresses to physical addresses

Back 16

at the time of memory allocation to the program.

there are 3 types of addresses used in a program before and after memory is allocated

Front 17

the 3 types of addresses before logical address is mapped to physical address

Back 17

1. Symbolic address - used in a source code. variable names, constants, and instruction labels are the basic elements of the symbolic address space

2. relative address- at the time of compilation, a compiler converts symbolic addresses to relative addresses

3. physical address - the loader generates these addresses at the time when a program is loaded into main memory

Front 18

main memory has 2 partitions

Back 18

1. low memory - OS is here

2. high memory - user process is here

Front 19

Define external fragmentation

Back 19

the type where memory is fragmented

Front 20

Define internal fragmentation

Back 20

the type where the memory is bigger than process so some is left unused which can't be used by other processes