On Mon, 4 May 2015, Alexandre Souza wrote: The CHEAPEST exorcisor, but containing a lot of extraneous other "features", such as BASIC in ROM, that are not in a dedicated exorcisor, is a microcomputer. You need a 20MHz dual trace scope, the analog alignment diskette, and enough computer functionality to select the drive, move the head to the correct track, and issue a READ command. For the purposes of using an AAD, the exorcisor does not do anything other than substitute for a computer. Some have some other useful features, but not needed for using an AAD. A DDD (Digital Diagnostic Diskette) is generally considered to not be as accurate for alignment as an AAD, but it does not require a scope, and does require a little bit more software. -- Grumpy Ol' Fred cisin at xenosoft.com