If you have a DDS2 drive, 120m tapes are the right ones to use. If your DDS2 drive isn't working correctly with them, it is broken. Perhaps you meant that 125m tapes (DDS3) don't work right in a DDS2 drive, which is quite true. Note that both 120m DDS2 tapes and 125m DDS3 tapes can actually be the same length: Marketing ECMA Marketing Specified Native Capacity Generation Standard "Length" Length Capacity (2:1 compression) -------------- -------- ---------- ------ -------- ----------------- DDS and DDS/DC 139 60m 3-60.5m 1.3G 2.6G 150,170 90m 3-92m 2G 4G DDS2 198 120m 10-125m 4G 8G DDS3 236 125m 10-125m 12G 24G DDS4 288 150m 10-155m 20G 40G Shorter tape lengths have been made for OEMs, but typically only tapes with lengths close to the specified upper limits have been available for retail sale. If you have a DDS(m) drive, do NOT use DDS(n) tapes for n>m. The oxide formulations are different, which will prevent data from being reliably stored. Also the tapes are thinner, and the earlier transports do not use tensioning aprorpiate for the later tapes. Newer drives are designed with the requirements for older generation tape in mind, so the older tapes can be used (at their normal storage density).