It does depend somewhat on the bit density, doesn't it? If it's at 800bpi, you take 8 tracks, (one's probably parity) and multiply the useable length by the number of bits per inch, and the rest depends on the data record format and whatever overhed there is for headers, CRC, etc. There are ANSI standards that apply to each density, so that's a good place to start. Dick -----Original Message----- From: Jim Arnott <jrasite(a)eoni.com> To: cctalk(a)classiccmp.org <cctalk(a)classiccmp.org> Date: Saturday, June 29, 2002 6:19 PM Subject: 9 track capacity