Choosing Storage for an Application

Choosing storage for an application means picking a device or medium that suits the job, then explaining why it suits it. More than one answer can be sensible — a USB flash drive or an external SSD might both work — so what counts is how well you justify your choice using the characteristics that matter.

Weigh up the characteristics

• Capacity — compare it with how much data must be stored and how large the files are. 200 high-resolution photos need far more room than a few text documents.
• Speed — compare it with how quickly data must be read or written. Files only copied onto storage to carry them can be slower; programs run from it need fast reading.
• Portability and durability — consider whether the storage will be carried, or used where it may be knocked or vibrated.
• Reliability — matters for storage kept a long time or used again and again.
• Cost — think about the purchase price and the cost per gigabyte, not just one or the other.
• Compatibility — does it need an extra drive or connection? A USB flash drive needs no separate drive, but an optical disc needs an optical drive.

Match the type to the job

Solid state storage suits portable use, places with knocks or vibration, fast access, low power and silence. Magnetic storage suits high capacity at low cost where the device will not be moved much. Optical storage suits cheap physical distribution or a small archive where low capacity and slow access are acceptable.

A worked example

A small family-run campsite takes bookings on a laptop in a wooden reception hut powered by a solar panel and battery. An SSD is a strong choice: it draws little power, has no moving parts to suffer when the laptop is carried out to a pitch, and opens the booking program quickly. The owner also keeps ten years of scanned paperwork and hundreds of site photos, rarely opened and never taken off site, so a high-capacity HDD is the better buy — room per pound counts for more than speed when files are only checked now and then.