Memory hook: Interface, protocol and form factor are different questions.
Must remember
HDDs use moving magnetic media; SSDs use flash. SATA is a storage interface/protocol family; NVMe uses a PCIe-based storage protocol. M.2 is a form factor that can carry different interfaces, so an M.2 drive and slot must agree on supported protocol, length and keying.
RAID 0 stripes for capacity/performance without redundancy; RAID 1 mirrors; RAID 5 uses distributed single parity; RAID 6 tolerates two drive failures; RAID 10 combines mirroring and striping with failure tolerance depending on which members fail. RAID is not a backup: deletion, corruption or a controller/site failure can affect the array. Rebuild time and degraded performance matter.
SATA data/power, PCIe slots, USB, Thunderbolt, HDMI, DisplayPort, Ethernet and audio connections carry different capabilities. An adapter may be passive or require active conversion; direction and resolution/refresh support matter. Display troubleshooting includes input source, cable, resolution, refresh rate, scaling, GPU output and monitor controls.
Bluetooth/USB peripherals can fail through pairing, drivers, power management, permissions or interference. Compare behavior on another supported port/device using a known-good cable. A working charger does not validate every data conductor.
Storage symptoms include SMART warnings, unusual HDD noises, read errors, low free space and high latency. Preserve important data before stress testing a potentially failing disk. A filesystem error and physical failure can coexist. Use appropriate diagnostics and verify restores when replacing drives.
Plan storage by capacity, random/sequential workload, endurance, latency, redundancy and recovery requirements rather than only advertised peak transfer rate.
Choose under exam pressure
| Requirement | Choice and reason |
|---|---|
| M.2 drive not detected | Check SATA versus NVMe support, slot/keying and firmware. |
| Need redundant disks | Choose an appropriate RAID design plus independent backups. |
| Display works at low but not high refresh | Check cable/adapter/bandwidth and supported mode. |
Traps
- M.2 does not automatically mean NVMe.
- RAID cannot undo accidental deletion.
Active recall
1. RAID 0 protects against how many disk failures?
None; loss of a member can lose the array.
2. What does RAID 1 do?
Mirrors data across members.
3. Why can an M.2 drive fit but fail?
The slot may not support its protocol or configuration.
4. What comes before heavy testing of a failing disk?
Protect/recover important data using the appropriate procedure.
5. Why can an adapter work only in one direction?
Signal conversion and protocol roles may be directional.