"2.8M" has an unformatted capacity of 4M
The disk that you linked a picture of says "406TPI"!
Therefore, it presumably has about three times as many tracks. (240?),
which, if it does a 1,000,000 bits per second, with track density the
same as "2.8M",
That should read "density within each track", as "track density" could
mean how close the tracks are to each other, and this is one third the
track to track distance.
would give it an UNFORMATTED capacity of 12M, and a formatted
(data) capacity of about 8.5M.
Density Tracks tpi bpi Coercivity Unformatted capacity per side
Triple[14] 240 406.5 36,700 6,500 KB
