Assume that the seek time in moving the disk arm head from logical block i to block j is proportional to |i – j|. Given that the arm head is currently positioned at block 75 and is in the midst of moving in the direction towards block 0, what is the sequence in which the enqueued blocks will be read with the i) SSTF, ii) SCAN, and iii) C-SCAN algorithms (picks up requests on way down only)?

answer: internal fragmentation is the difference between the (fixed) size of a memory hole and the data within in that memory. for example, if a 1,024 byte block of memory holds 800 bytes of data, then the 224 bytes difference is considered lost to internal fragmentation.

external fragmentation occurs when the sum of memory fragments is large enough to satisfy a request, but the holes are non-contiguous and the request cannot be satisfied. this can occur when memory is dynamically allocated and freed.

explanation: