IN CLASS NOTES FOR MARCH
Wednesday, March 31:
Discussion on Cache to Main Memory and from Main memory to Disk Mapping.
A virtual address consist of a page no. and an offset. This lies in the hardware aspect. In software aspect, a [age map table entry consist of a page frame address and a Secondary Storage Page Location. It also has a residence Bit.
A translation Lookaside buffer Entry has a disk address. It has a virtual page address and a page frame address. This hardware address has a residence bit, Dirty Bit and a reference bit.
Monday, March 29:
~ Math 145 Exam III , ~ Skipped class
Notes obtained covering some points at the end of chapter 11, memory management. Defining Best Fit, Worst Fit and First-Fit and Next-Fit.
Friday, March 26:
~ Absent from class ~
Wednesday, March 24:
Briefing on placement of OS in memory and single Contiguous Memory Management.
Reason OS is placed at a lower address is for easier access, less memory allocation problem compared to being placed in the middle or high address. System do not have to compute the actual size of memory to do proper allocation
Internal Fragmentation is wasted space owned by a process/user
External Fragmentation is wasted space owned by the OS itself.
Monday, March 22:
~ Absent from class ~ Dr.Kaugars was stand in for class lecture
Friday, March 19:
~ Absent from class ~ Dr.Kaugars was stand in for class lecture
Wednesday, March 17:
Discussion about deadlock. 4 Different kinds of prevention strategies:-
Mutually Exclusive, Hold & Wait , Circular waiting and No preemption.
Solution techniques are:-
Ignore, Detect and Recover, Prevent and Avoid
Monday, March 15:
~ Absent from class because of ECE 350 Project Presentation ~
Friday, March 12:
Emphasized on semaphores. It has the operation of P(s) and V(s) which stand for In and Out. Semaphores are devided into 2 types:-
a) Binary [0 and 1 values] and b) General/Counting which involves the value of [1,n,-n.]
Wednesday, March 10:
Learned about the term "Mutual exclusion" which meant having only one process to be in the critical section at one time. Also, defining race condition between processes is the interleaving, speed and order of the processes. Some ways to solve Critical section issue is to implement a lock. However, this creates a "Busy-Wait" situation for the process that is waiting to use the resources.
Monday, March 8:
Introduction to Synchronization.=> Means coordination of activities among processes.
The reason for Synchronization is for Protection & Sharing.Discussing shared resources in Hardware and Software. Printer being an example of a non-sharing hardware resource. While the memory is a shared hardware resource as one or more process can use it at the same time.
Friday, March 5:
~ Spring Break ~
Wednesday, March 3:
~ Spring Break ~
Monday, March 1:
~ Spring Break ~