The 8 inch floppy disk (or diskette) was a magnetic storage disk for data that was introduced commercially by IBM in 1971.
It was designed by a team led by David L. Noble in IBM as an inexpensive way to load data into the IBM System/370, and was initially simply a read-only bare disk (the 'Memory Disk') holding 80 KB of data, or the equivalent of 3,000 punched cards.
By the time of it's commercial launch, it had been enclosed in a 203.0 mm x 203.0 mm x 1.6 mm plastic envelope lined with fabric, to protect the disk and minimise the problems caused by dust.
The first read-write version was introduced in 1972 by Memorex, and could hold 175 KB on 50 tracks (with 8 sectors per track). It was hard-sectored and had 8 sector holes (and an index hole) on the outer diameter.
Further improvements led to teflon-lubricated fabric liners, teflon-coated disks and an eventual increase in capacity to 1.2 MB in the double-sided double density (DSDD) version in 1977.
It was eventually displaced by the 5.25-inch floppy disk ((initially called the minifloppy to avoid confusion between the two sizes) developed in 1976 by Shugart Associates, a company founded by Alan F. Shugart who previously worked at IBM on the development of the 8-inch floppy.
The 8-inch floppy disk is briefly seen in the 1983 film War Games, along with an acoustic coupler.