Had 16-bit DOS a memory access limitation of 1 MB? If yes, how?

Question

I am reading a OS Development series, in which there is a statement,

Due to 16 bit mode limitations, DOS could not access more than 1 MB of memory

Is this true? If I do 2^16, it gives 64KB, so why the article is saying 1MB limitation?

Answer 1

Google knows the answer to this. For example this Wikipedia article on DOS memory management states that:

The Intel 8088 processor used in the original IBM PC had 20 address lines and so could directly address 1 MB (2²⁰ bytes) of memory

Other stuff you can find with google will give you lots more detail.