Questions about example sentences with, and the definition and usage of "Hdds"

A: × HDDs used to be the most fragile parts in PCs, but HDDs have been changed to SSDs.
✓ HDD's were once the most fragile parts in PCs, but many HDD's have since been changed to SSD's.

× They are very steady, so we can deal with PCs at ease, though backup is still very important.
✓ SDD's are very reliable, so we can deal with problems at ease, but backing up your data is still very important.

- Use of apostrophes.

- 'were once' is more formal.

- 'since' denotes they were changed in the past not the present.

- 'many' (HDD's are still used).

- 'reliable' is a better translation.

- 'but' works better than 'though' here.

-'backing up your data'. More detail.