I agree, it isn't a copy type operation. It is a creation type operation. The cats eye is created by two tones written such that it is one cycle different per revolution. Each tone it offset by one half of the track width. Cats eye don't tend to work well with digital sampling scopes unless they have a large sweep buffer and can keep the high speed sample rates at a slow sweep speed of a single full revolution. I don't know of any cheap ones that don't change the sample rate with the sweep rate. The next one is single tones are placed as burst at varying radial distances. This has a similar problem for sampling scopes. When used, it looks like steps that one puts the largest step in the center of the rotation, relative to the index. The track centers can be aligned with magnetic material, similar to what is used for magna-flux work, as far as I know and a micrometer to measure the offset to the center hole. It would be far easier to create a new disk than to try and copy one. I can't imagine how one might copy one. Dwight
________________________________ From: Chuck Guzis via cctalk <[email protected]> Sent: Wednesday, October 2, 2024 5:36 PM To: Ali via cctalk <[email protected]> Cc: Chuck Guzis <[email protected]> Subject: [cctalk] Re: Dysan Alignment and Performance Testers On 10/2/24 16:04, Ali via cctalk wrote: >>> I assume it's not easy to copy alignment disks, but I guess I will >> find out. >>> >> >> It's actually not possible to copy them. Not for any "copy protection" >> reasons, but just the very nature of the analog signal laid down on the >> disk. No "regular" disk drive can recreate the signal. >> > > Chuck had actually talked about how to make one on a VCF post a while back: > https://forum.vcfed.org/index.php?threads/greaseweazle-v4-reading-m1-5-25-fl > oppies-on-a-sa400a-drive.1242918/post-1380519. Didn't sound like it was > going to be as easy as copying a disk... ;) No, not easy, but possible, given skill, equipment and patience.
