I did asic design on CD and DVD burners for a number of years but it was years ago and before lightscribe was an option, so I can't really compare burning data to a disc to lightscribe.
I don't know as much about the physical process but I don't know what is meant by "test grooves". My understanding is that burning a cd doesn't actually put grooves on it like a vinyl record but rather turns the transparent polycarbonate dark so that it does not reflect light from the aluminum disk underneath. So that would be the first issue/question, whether the physical process will actually do what they want to do. The second question is one of synchronization between the laser and the spinning disk. I worked on the CD read section of the chip, taking a stream of high speed data, de-interleaving it and running it through a 10b8 error recovery block, so I'm not as familiar with DVD's as CD's but I'm not sure that there is any sort of "index hole" marker on the CD to physically align the head back to the same spot. audio CD's are one big, long spiral of data starting from the inside and working out. DVD tracks are concentric circles with sectors and whatnot. But I don't know of there is any kind of index hole so that you could put down a stream of 1's on one track, move the head out, and then put another stream right alongside the previous stream. If the only requirement is to create a specific pattern on a single track, it should be possible. But if you want to lay down data on different tracks and have them be physically aligned with each other, I'm not sure that's even possible. The other bit of weirdness is that the RPM changes as you move the head to different tracks. The goal is to achieve constant linear speed over the track which gives you constant data rates coming off the head. Back in the day, audio CD drives were built with only very small data buffers in silicon, usually just enough to perform de-interleaving, 10b8 error correction on one block (48 bytes) while receiving the next block. So, as the head spiraled further out from the center, the disk would be spun at slower and slower rpm's. I think DVD's generally follow this Constant Linear Velocity approach, which means you've got more data in a track as you move further out from the center. This doesn't make it impossible but if you want a couple of "test grooves" to lay side by side then they'll default to being the same linear length, not the same arc of rotation. Lastly, based on how our chips worked, I can't even imagine getting direct control of the heads through software. Maybe other chips let you have more direct control, but there is so much data flying that most of it is automatic. By the time the serial data comes off the disc, its already run through serial de-interleaving, 10b8 error correction, and a bunch of other hardware blocks before the software ever sees it. prior to that point, its just moving too fast for software to keep up. I think the best you could hope for is to work within the existing DVD format and simply try to control what track the head is on and then give it a block of data to write. And even then I don't think there is any way to align one track to the track next to it. Anyway, this is all very fuzzy recollections of stuff I worked on a long, long time ago, in a galaxy far away. Someone more current might be able to do it no problem. Greg > My son-in-law got this from his boss. I assume he wants to burn art into a > lightscribe DVD. The place of business is in East Cambridge, his wife used > to live 2 doors away from me while she was married to someone else. > > ------- > The objective is to burn many grooves on the DVD that will NOT be holding > any data or pictures. Imagine that you have a pattern template that you > have drawn using some drawing tool and you want to burn "grooves" on the > DVD using the DVD writing head. There are "artist" specific software that > do this however, they are not precise enough for my friend's purposes > which is to create "test grooves" to test various organic compounds using > low voltage electricity. > > So I guess what I am looking for is someone that can write a firm ware to > move the head AND provide a "crude" user interface to draw simple straight > lines (for the template) and use the DVD writer to etch the grooves along > the lines created by the user. > > Here is the device: HP CDDVDW TS-L633N 0300 195 (LightScribe) > > They will pay good money for an electrical engineer that can do that. > > I hope this is helpful. This will not be used in any commercial capacity. > It is only for testing in a laboratory environment. Thanks. > ------- > > -- > Jerry Feldman <[email protected]> > Boston Linux and Unix > PGP key id:3BC1EB90 > PGP Key fingerprint: 49E2 C52A FC5A A31F 8D66 C0AF 7CEA 30FC 3BC1 EB90 > > > _______________________________________________ > Hardwarehacking mailing list > [email protected] > http://lists.blu.org/mailman/listinfo/hardwarehacking > -- _______________________________________________ Hardwarehacking mailing list [email protected] http://lists.blu.org/mailman/listinfo/hardwarehacking
