In operating system storage architecture, what is defined as 'Double Buffering'? (Set 45)
Definition of Double Buffering: Using two memory buffers so one buffer is processed by CPU while the other receives I/O data.
Which memory partitioning scheme avoids external fragmentation completely? (Question 43)
Paging divides physical memory into fixed-size frames and logical memory into pages, completely eliminating external fragmentation.
A process references pages in the order: 1, 2, 3, 4, 1, 2, 5, 1, 2, 3, 4, 5. Using LRU page replacement with 3 page frames initially empty, how many page faults occur? (Question 42)
Tracing LRU with 3 frames: [1] (f1), [1,2] (f2), [1,2,3] (f3), [4,2,3] (f4), [4,1,3] (f5), [4,1,2] (f6), [5,1,2] (f7), [5,1,2] (hit), [5,1,2] (hit), [3,1,2] (f8), [3,4,2] (f9), [3,4,5] (f10). Total = 10 page faults.
What is the 'Ostrich Algorithm' in Operating System design?
The Ostrich Algorithm refers to ignoring deadlock potential (sticking one's head in the sand). Most general-purpose OSs (like UNIX, Linux, Windows) adopt this strategy because prevention/detection algorithms impose heavy runtime overhead.
Consider a logical address space of 32 pages of 1 KB each, mapped onto a physical memory of 64 frames. How many bits are required in the logical address?
Logical Address = Page Number + Offset. 32 pages = $2^5$ (5 bits). 1 KB page size = $2^10$ bytes (10 bits offset). Total logical address bits = 5 + 10 = 15 bits.