Tutor profile: Ian S.
Subject: Information Technology
What is RAID and why is it useful?
RAID stands for Redundant Array of Independent Disks. By combining storage from more than one disk, redundancy and/or data loss protection. A combination of 'layering' data, and splitting data is used across the disks, allowing faster access speeds, or recovery in case of failure of one of the disks.
Subject: Software Engineering
Why are Version Control Systems (VCS) considered essential tools by software engineers?
Imagine you want to create a application. You'd design it, and then you start coding. You're almost done, when your cat walks on the keyboard, deleting most of your project! Version Control Systems (VCS), are designed to solve this problem. They store a history of your work at different points in time, and allow you to easily explore your code at that point, or even replace the code you have with an earlier or later version.
Subject: Computer Science (General)
What is the complexity, in Big-O notation, of the following algorithm and why:? procedure bubbleSort(A : list of sortable items ) n = length(A) repeat swapped = false for i = 1 to n-1 inclusive do if A[i-1] > A[i] then swap( A[i-1], A[i] ) swapped = true end if end for until not swapped end procedure /* bubblesort Pseudocode implementation from https://en.wikipedia.org/wiki/Bubble_sort */
The complexity of the bubblesort is O(n) in the best case, and O(n^2) in the worst. This is misleading however, as the average case is also O(n^2). The bubblesort algorithm works by walking through the data over and over, comparing each pair of items, and switching them if needed. This can get out of hand quickly for large, or not well-ordered data. For this reason, the bubblesort is very limited in it's practical application.
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