7.1. ESI Sources 7.1.1. Individual Custodians 7.1.1.1. Key Individual Custodians 7.1.1.2. Tier 2 Individual Custodians 7.1.1.3. Tier 3 Individual Custodians 7.1.2. Organizational Custodians 7.1.2.1. Key Organizational Custodians 7.1.2.2. Tier 2 Organizational Custodians 7.1.2.3. Tier 3 Organizational Custodians 7.1.2.4. Organizational System Generated 7.1.3. Legacy Custodians 7.1.3.1. Key Legacy Custodians 7.1.3.2. Tier 2 Legacy Custodians 7.1.3.3. Tier 3 Legacy Custodians 7.1.3.4. Legacy System Generated 7.1.4. Third Party Custodians 7.1.4.1. Key Third Party Custodians 7.1.4.2. Tier 2 Third Party Custodians 7.1.4.3. Tier 3 Third Party Custodians 7.1.4.4. Third Party System Generated 7.1.5. Non Party Custodians 7.1.5.1. Key Non Party Custodians 7.1.5.2. Tier 2 Non Party Custodians 7.1.5.3. Tier 3 Non Party Custodians 7.1.5.4. Non Party System Generated 7.2. ESI Systems 7.2.1. Communication Systems 7.2.1.1. Email Systems 7.2.1.2. IM Systems 7.2.1.3. Audio Systems 7.2.1.4. Video Systems 7.2.1.5. Mobile Communications Systems 7.2.1.6. Collaboration Systems 7.2.2. Data Storage Systems 7.2.2.1. Structured Data Storage Systems 7.2.2.2. Unstructured Data Storage Systems 7.2.3. Backup Systems 7.2.4. Archival Systems 7.2.4.1. Data Retention Archival Systems 7.2.4.2. Litigation Hold Archival Systems 7.2.5. Legal Systems 7.2.6. Information Management Systems 7.2.7. User Systems 7.3. ESI Types 7.3.1. Communications 7.3.1.1. Email 7.3.1.2. IM 7.3.1.3. Audio 7.3.1.4. Video 7.3.2. Communications Storage Formats 7.3.2.1. Individual Messages 7.3.2.2. Containered Messages 7.3.2.3. Enterprise Stored Messages 7.3.2.4. Third Party Hosted Messages 7.3.3. Office Files 7.3.3.1. Word Processing 7.3.3.2. Spreadsheet 7.3.3.3. Presentation 7.3.4. Structured Data 7.3.4.1. Raw Relational Database 7.3.4.2. Structured Data Applications 7.3.4.3. Process Management Systems 7.3.4.4. Structured Storage Systems 7.3.5. Graphics 7.3.5.1. TIFF 7.3.5.2. PDF 7.3.5.3. BMP 7.3.5.4. GIF 7.3.5.5. JPEG 7.3.5.6. PNG 7.3.5.7. CAD 7.3.6. Audio 7.3.7. Video 7.3.8. Foreign Language 7.3.8.1. Translation 7.3.8.2. Character Sets 7.3.8.3. Unicode 7.3.8.4. Non-Unicode 7.3.9. Residual Data 7.3.9.1. File Fragments 7.3.9.2. Deleted Files 7.3.9.3. Buffers 7.3.9.4. Caches 7.3.10. System Generated Data 7.3.10.1. Logs 7.3.10.2. Audit Reports 7.3.10.3. System Alerts 7.4. ESI Status 7.4.1. Online & Production 7.4.2. Backup 7.4.3. Archival 7.4.4. Offline 7.5. Media Types 7.5.1. Hard Drives 7.5.2. Tapes 7.5.3. Portable Storage Devices 7.5.3.1. Flash Drives 7.5.3.2. DVDs 7.5.3.3. CDs 7.5.3.4. Floppy Disks 7.5.3.5. Optical Disks 7.6. Forms 7.6.1. Native 7.6.2. Near Native 7.6.3. Near Paper 7.6.4. Near Paper