Question 1

Why does my drive show less storage than advertised?

Accepted Answer

Two separate reasons that compound, and only one of them is arguably anyone's fault.

**Reason one: decimal versus binary units.** Storage manufacturers use **decimal** prefixes, where 1 GB means 1,000,000,000 bytes. Operating systems — Windows in particular — have traditionally displayed **binary** quantities, where the underlying unit is 1,073,741,824 bytes, while still labelling them "GB".

The two disagree by about 7% at gigabyte scale and roughly **9.3% at terabyte scale**, and the gap widens with each prefix. This is why a **1TB drive shows as about 931GB**, and a 500GB drive as about 465GB. Nothing is missing — the same bytes are being described with a different unit.

**The formally correct binary units are GiB and TiB** — gibibytes and tebibytes — and macOS and most Linux distributions now display decimal GB, matching the manufacturer, which is why the same drive reports differently on different systems.

**Reason two: space that genuinely is not available to you.**

**Filesystem overhead** — the structures tracking where everything is stored.

**Recovery partitions**, frequently several gigabytes, for restoring the system.

**The pre-installed operating system**, which on a laptop can be a substantial share of a small drive.

**Over-provisioning on SSDs.** A reserve of cells kept aside by the controller for wear levelling and replacing failed blocks. It is invisible and is what keeps the drive reliable and fast.

**Reserved space** for system files, hibernation files, virtual memory and snapshots — macOS in particular reserves space for local Time Machine snapshots, which is why "available" and "free" differ there.

**What this means in practice:**

**The discrepancy is predictable.** Multiply the advertised capacity by about 0.909 for terabyte drives to estimate what a binary-reporting system will show.

**Drives perform poorly when nearly full**, SSDs especially, so treat the last 10% as unavailable regardless.

**If the shortfall is much larger than expected**, look for recovery partitions, hibernation files, or snapshots rather than assuming a defect.

Question 2

What is the difference between Mbps and MB/s?

Accepted Answer

A factor of eight, and it accounts for most of the confusion about why a fast broadband connection produces download speeds that look disappointingly slow. The two units: Mbps — megabits per second.

Question 3

Why is my computer running out of disk space when I have not saved anything?

Accepted Answer

Space disappears into places you do not see in your documents folder, and a handful of categories account for nearly all of it. System snapshots and restore points are usually the largest. Both major

Question 4

Why is my external hard drive not showing up?

Accepted Answer

Determine first whether the drive is being detected at all, because that single fact separates two very different problems. The disk management utility on your system lists physical disks regardless

Question 5

How to resolve device storage issues?

Accepted Answer

To resolve device storage issues, delete unnecessary files, clear app cache, uninstall unused apps, use cloud storage, optimize media files, or perform a factory reset.

Question 6

Why is my phone storage full when I deleted everything?

Accepted Answer

Because the things occupying the space are usually not the things you were deleting, and much of it is invisible in the ordinary file view. The usual culprits, roughly in order: App caches. Apps

Question 7

Why is my scanned PDF so large?

Accepted Answer

Because a scan is not a document — it is a collection of photographs, and it is stored as image data rather than as text. The difference. A PDF created from a word processor stores text characters

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