A 5.25-inch diskette is an older diskette that first development in 1976 and later became a standard in 1978. The diskettes were popular throughout the 1970's and early 1980's and are similar to the 3.5-inch floppy diskette with a lesser capacity and larger dimension. Unlike their rigid, 3.5" counterparts, the 5.25-inch diskettes are flimsy.
The 5.25-inch diskettes were available in a capacity of 160 KB single side, 360 KB low density and 1.2 MB high density sizes. By 1994, the 5.25-inch disk was extinct and was replaced by the preferred 3.5-inch disks.
The 5 1/4" floppy diskette was really floppy (flimsy), hence the name. As you can see in the above illustration, the 5 1/4" floppy does not have many involved components. First, you will notice the write protection tab that would be found on diskettes that allowed information to be written to them. To write-protect the diskette, a piece of tape is placed over the hole, or if there is no hole the diskette is already write-protected.
Second, notice the large hole in the center of the floppy diskette. This hole allowed the platter in the floppy to be rotated allowing the information to be read from the read/write access hole.
Third, notice the index hole, this was the computer's way of knowing where the starting point of the sector by having a hole punched in the film disc in the plastic casing.
Finally, the write access hole is where the computer floppy drive would write the information to the diskette.