Q:

What is a fixed width binary data format?

What is fixed width binary data format and what's an example of it? If it's 8x8 fixed width binary, what does this mean and how much memory would it occupy in terms of bits?
I googled fixed width binary data format and searched stackoverflow. A different post on stackoverflow on how to handle fixed width binary (Ideal Field Type For Fixed Width Binary Data) wasn't helpful.

A:

There are two ways to store data : Variable length and fixed length. Variable length data format won't use max length every time while fixed one will use max provided fixed length every time. Fixed data format will use chunks/blocks of fixed size to store data.
Due to same, variable length uses less space but can't provide indexing while fixed length uses more space but you will get indexing as you can jump directly to the specified chunk.
Ex : In case of fixed n length data format. Data chunks of n length will be created and you can jump directly to X'th chunk by calculating memory index X*n .
For understanding : https://documentation.microfocus.com/help/index.jsp?topic=%2FGUID-0E0191D8-C39A-44D1-BA4C-D67107BAF784%2FBKFHFHORGSS014.html
As you have specified fixed width binary data format. So it is fixed length/width binary type format. 
8x8 fixed width binary = 8 bytes fixed width data format = 64 bits fixed width data format .
It will store chunks/blocks of 64 continuous bits in memory.
Ex : In case of 8x8 fixed width binary type data format, you may try to store a data which requires 1 byte only but it will be stored in 8 bytes by padding 0's to make it fixed length.

