Q: disk0s2: 1/0 error

Hi

can you aid here

i have apple macbook 13" which when starts shows grey screen with cog spinning only and does nothing else

i have now started in apple v mode and its showing start up in FIPS User space post which all show test success etc

further down im seeing 

disk0s2: 1/0 error.

would you be so kind and aid here please

many thanks