Choosing Appropriate Storage

This lesson covers how to choose the right storage technology for a given scenario, considering factors such as capacity, speed, portability, durability, and cost. This is part of OCR J277 Section 1.2.2.

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Factors to Consider When Choosing Storage

When selecting a storage device, you must weigh up five key factors:

Factor	What It Means	Questions to Ask
Capacity	How much data can the device store?	How large are the files? How many files need storing?
Speed	How fast can data be read from or written to the device?	Is fast access important for this task?
Portability	How easy is it to transport the device?	Does the device need to move between locations?
Durability	How resistant is the device to physical damage?	Will the device be used in harsh conditions or while moving?
Cost	How much does the device cost (initial price and cost per GB)?	What is the budget?

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Applying the Factors to Different Storage Types

Magnetic (HDD)

Factor	Rating
Capacity	Excellent — up to 20+ TB
Speed	Moderate — 100-200 MB/s
Portability	Moderate — portable HDDs exist but are bulky
Durability	Poor — moving parts can be damaged by shocks
Cost	Excellent — lowest cost per GB

Best for: Large backups, file servers, storing media libraries, desktop storage where speed is not critical.

Optical (CD/DVD/Blu-ray)

Factor	Rating
Capacity	Low — 700 MB (CD) to 25 GB (Blu-ray)
Speed	Slow — much slower than HDD or SSD
Portability	Excellent — discs are small, lightweight, and easy to transport
Durability	Moderate — can be scratched; sensitive to heat and sunlight
Cost	Very low per disc

Best for: Distributing software or media, archiving small amounts of data, portable data transfer where the recipient has an optical drive.

Solid-State (SSD / Flash)

Factor	Rating
Capacity	Good — 120 GB to 8 TB (SSDs); smaller for USB drives
Speed	Excellent — 500-7,000 MB/s
Portability	Excellent — USB drives and SD cards are tiny
Durability	Excellent — no moving parts
Cost	Moderate to high — more expensive per GB than HDD

Best for: Operating system drives, laptops (durability matters), portable file transfer (USB drives), cameras and phones (SD cards).

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Storage Decision Tree

Use the following decision flow to pick a storage technology from the requirements of a scenario:

graph TD
    Q1{"Speed critical?"}
    Q1 -->|Yes| Q2{"Portable<br/>device?"}
    Q1 -->|No| Q3{"Bulk capacity<br/>and low cost<br/>most important?"}
    Q2 -->|Yes| SSD1["SSD / USB flash"]
    Q2 -->|No| NVME["NVMe SSD<br/>(internal)"]
    Q3 -->|Yes| HDD["Magnetic HDD<br/>or tape"]
    Q3 -->|No| Q4{"Distribute many<br/>read-only copies?"}
    Q4 -->|Yes| OPT["Optical disc<br/>(CD / DVD / Blu-ray)"]
    Q4 -->|No| HDD

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Scenario-Based Practice

Scenario 1: A photographer needs to store thousands of high-resolution photos

Factor	Requirement
Capacity	High — RAW photo files are large (20-50 MB each)
Speed	Moderate — fast enough to transfer and edit
Portability	Moderate — may work on location
Durability	High — may be used while travelling
Cost	Moderate budget

Recommendation: An external SSD provides fast transfer speeds, high durability (no moving parts), and decent capacity. For archiving older photos, a large HDD offers cost-effective long-term storage.

Scenario 2: A school needs to distribute revision materials to 500 students

Factor	Requirement
Capacity	Low — a few hundred MB of documents and videos
Speed	Not critical
Portability	High — each student needs a copy
Durability	Moderate
Cost	Very low (multiplied by 500)

Recommendation: USB flash drives or online cloud storage would be suitable. CDs could work but many modern laptops lack optical drives. Cloud storage avoids physical media costs entirely.

Scenario 3: A gaming PC needs fast loading times

Factor	Requirement
Capacity	Moderate to high — games are 50-100+ GB each
Speed	Critical — fast loading improves gaming experience
Portability	Not needed — desktop PC
Durability	Not critical — stationary use
Cost	Moderate budget

Recommendation: An NVMe SSD for the operating system and frequently played games, combined with a large HDD for storing less-played games and media files.

OCR Exam Tip: In scenario questions, always evaluate multiple factors before making a recommendation. State the chosen device, then justify your choice by referencing at least 2-3 relevant factors.

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Quick Reference: Which Storage for Which Situation?

Situation	Best Storage	Key Reason
Operating system drive	SSD	Speed (fast boot and load times)
Large backup archive	HDD	High capacity, low cost
Portable file transfer	USB flash drive	Small, durable, portable
Camera storage	SD card	Compact, durable, fast enough
Distributing software	Cloud / USB drive	Accessible, no optical drive needed
Long-term data archive	Magnetic tape / HDD	Very low cost per TB

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Summary

• Choosing storage requires balancing capacity, speed, portability, durability, and cost (OCR J277 1.2.2).
• HDDs offer the best capacity per pound but are slower and fragile.
• SSDs offer the best speed and durability but cost more per GB.
• Optical media is cheap and portable but low capacity and slow.
• Always match the storage type to the specific needs of the scenario.

Key Vocabulary: capacity, speed, portability, durability, cost per GB, NVMe, SATA, flash memory, archive.

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Extended Worked Example: Sizing Storage for a Wedding Photographer

Sophie is a professional wedding photographer setting up her business. She needs to choose storage solutions for three different jobs: on the camera during the shoot, for editing in the studio, and for long-term archiving. Each role has different requirements, and this worked example shows how the five factors drive three different choices.