Secondary Storage
Comparing the three main technologies: Optical, Magnetic, and Solid State.
Optical
A laser shines onto the spinning disc to read data from the reflective surface (e.g., CD, DVD, Blu-Ray).
The 6 Characteristics
- Capacity: Low (700MB - 50GB)
- Speed: Slow
- Portability: High (Very light)
- Durability: Medium (Scratches easily)
- Reliability: Medium (Degrades over time)
- Cost: Very Low
Magnetic
A mechanical moving arm reads magnetic fields on spinning metal platters (e.g., Hard Disk Drive, Magnetic Tape).
The 6 Characteristics
- Capacity: Huge (TB to PB)
- Speed: Medium
- Portability: Low (Heavy, requires power)
- Durability: Low (Moving parts break if dropped)
- Reliability: High (Tried and tested)
- Cost: Low (Best price per GB)
Solid State
Uses flash memory chips tracking electrical charges with absolutely zero moving mechanical parts (e.g., SSD, USB, SD Card).
The 6 Characteristics
- Capacity: High (TBs)
- Speed: Very Fast
- Portability: High (Small and light)
- Durability: High (Robust, no moving parts)
- Reliability: High (Limited read/write cycles, but lasts years)
- Cost: Expensive
The Storage Lab
Read the client request and select the BEST storage device for the job.
Client: Video Editor
"I need to store 4TB of 4K video footage. I edit directly from this drive, so speed is extremely important. My budget is unlimited."
Master of Sales?
Test your knowledge in The Storage Shop. Match customers to the right device.
Open The Storage ShopCheck Your Understanding
1. Why is Solid State storage vastly faster and more durable than Magnetic storage?
2. Which characteristic makes Optical media (like CDs/DVDs) still somewhat relevant today?
3. A mountain-biker wants a GoPro camera to record trail rides. Which storage is paramount?
Written Exam Scenario (AO2/AO3)
"A school needs to upgrade the cloud servers in their stationary server room. The IT Technician insists they should buy Solid State Drives (SSDs) because they are the fastest. The Head of Finance refuses and insists they buy Magnetic Hard Disk Drives (HDDs). Evaluate the Head of Finance's decision based on the scenario." (4 marks)
Identify Property (Cost): Magnetic HDDs have a significantly lower Cost-per-Gigabyte compared to Solid State Drives.
Identify Property (Capacity): A school serving hundreds of students requires massive Capacity for user files, which HDDs easily provide cheaply.
Apply to Scenario (Durability): While SSDs are more durable, the scenario states the server room is stationary. The drives will never be moved or dropped, so the durability and portability of an SSD is not a required characteristic here.
Conclusion: The Head of Finance is correct. Buying massive arrays of SSDs for static cloud storage would be an enormous waste of budget, as the high-capacity, low-cost Magnetic HDDs perfectly fulfill the stationary requirement.