An American happily exiled in Barnsley may have solved a problem that has defeated all-comers for years - how to protect tape-based software.

Jim Lamont, head of a tape duplication business in Barnsley, has applied for a patent on the idea that he refers to as Copylock. Ironically, he may have to change the name since Export Software International already uses it on a disk system (Issue 38). But Mr. Lamont's Copylock applies only to tapes and he claims that it is foolproof.

"You can't make a copy from one cassette recorder to another," he says. "It can't be copied by a machine code copier, nor could it ever be."

Exactly how the idea works is a subject that Mr. Lamont is not about to explain too precisely. "It's a coded imprint, invisible in use, on the master tape. It only appears when somebody tries to copy it," he says. "We put it on to the master tape as the program itself goes on. That involves some specialised equipment, but you can buy that for about £200."

JLC, the company that has developed Copylock, intends to licence it such that the price of applying it to tapes should not work out at higher than 1p or 2p per copy. Mr. Lamont commented: "Every tape that's pirated hurts us as well as the software houses, and hence the customers - this idea won't increase costs one little bit."

"Copylock is something we've been trying to do for about two years, and we've been putting it together piece by piece," he said. "It includes a very short program mingled into the main one and some electronics to put the imprint on to the tape - we've had to look at it from the duplicator's point of view."

PCN hopes to test Mr. Lamont's claims for Copylock in a forthcoming issue. Anybody interested should contact JLC on 0226 87707.