Section+1,+Table+4+-+Hardware+&+technology+strategy+&+planning


 * __Week 4__**
 * Slide 4**
 * __Week 4 Keywords__**
 * __Technology Hype Circle__**
 * __Information Technology Strategy: Three Misconceptions__**

__3 misconceptions:__
 * The IT strategy should solely derived from a thorough review of organizational strategies and plans
 * The IT strategy should be dominated by a focus on defining needed application systems
 * The IT strategy is better if it is developed by using a rigorous methodology

3 Ways to allocate space on a hard drive
 * contiguous
 * linked
 * indexed

Contiguous Model
 * requires each file to occupy a set of contiguous blocks on the disk
 * simple- file designations only need to include the starting location (#) and how many blocks are required
 * Dynamic storage allocation is difficult
 * the problem of external fragmentation
 * Allocation voes
 * files can't grow

Linked Model
 * solves problem of contiguous allocation
 * Each file is linked list of disk blocks- scattered anywhere on the disk
 * No external fragmentation- files can grow
 * file allocation tables uses

Indexed Model
 * solves external fragmentation and size declaration issues with contiguous allocation
 * each file contains index block
 * However suffers from wasted space

FAT (File Allocation Table)
 * FAT has an entry for only disk block
 * FAT entries rather than blocks themselves are linked
 * Disk sectors are grouped into clusters

Fragmentation
 * as computer files are added/deleted, parts of files tend to become scattered all over the disk
 * "Holes" are left in the file system that are too small to fill
 * Slows performance of read/write/access
 * Defrag must be run to rearrange

Types of Fragmentation
 * Internal- allocate storage without using it
 * External- free space divided into small pieces over time
 * Data- data broken in memory into many small pieces due to external fragmentation