[cctalk] Re: LS120, LS240, Floptical Drives and DD, HD, ED, and ?TD? drives

On Tue, 28 Mar 2023, Ali via cctalk wrote: 3.5" disks for "720K" and "1.4M" are 135TPI. 80 tracks. An exception was the Epson Geneva PX-8, which was 67.5TPI, with 40 tracks. YES, that disk has about three times the track to track density of a "normal" 3.5" disk. With three times as many tracks, using otherwise identical parameters of "2.9M", it would have three times the capaciy. They could also have tracks further in and/or further out, to have slightly more than 24 tracks. Also, of course, beware of how many bytes are in a "megabyte". A "MebiByte" is 1,048,576 bytes. (2^20, or 1024*1024) Non-computer people often call 1,000,000 a "megabyte" (10^6) "1.4M" disks (1,474,560 bytes of data / 1.474 SI Megabytes / 1.40625 Mebibytes) are often called "1.44M", because that number is derived from 1,024,000 bytes per "megabyte" (2^10 * 10^6, 1000 * 1024), giving 1.44. I can find no defensible reason for that corrupted size for a "megabyte". Therefore, I call them "1.4M" (1.40625), NOT "1.44M" -- Grumpy Ol' Fred cisin(a)xenosoft.com