Thanks guys I'll report back to him. On 05/12/2014 02:28 PM, Greg London wrote: > 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 >> >
-- 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
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