Hello all... I have a really interesting question that I would like answered. Is it possible to create a CDRW drive from scratch? I have a few junk drives that don't work and would like to use these as parts for a new and hopefully better computer drive. Any thoughts/ideas/websites/info is much wellcome/needed. Thanks.
Lyos Gemini Norezel
P.S.-Are these drives proprietary? In other words would I have to devise one on my own?

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Hi Everyone,

Please study, extensively, material on laser safety before embarking on a project that involves lasers. Lasers can be very dangerous!

Cheers,

Paul

Hey Paul... Yes I do understand the dangers of working with lasers, I only build the damn things. Alright... here's the idea behind my post. I'd like to create a cdrw drive that would act like a small hard drive. It would contain 2 lasers (each doing the read/write operations) with the disk actually being two cdrw's connected together by the label side (ie., the writing surace on the outside). This is where the hard drive technology is gonna come in handy... the disk would be constantly written to and over written just like a hard disk, and the disks will be interchangeable so you could have more than one OS if you wanted it. Anyone have any thoughts/comments on this?
Lyos Gemini Norezel

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Hi, Well, i have to imagine its possible, after all, all devices had to have at least one prototype. When you said you build them, did you mean cd drives or lasers? Cd drives, especially cdrw driver are pretty complex beast, look at linux - untill recently - there wasn't even a graceful way to write to them, you had to make the os think it was a SCSI drive, which is a bit of a hack. But, I digress - what would be the system you intent to run it on? CdRW drives are very complex beast, just for single sidded disks, when you add another disk, you are insreasing the complexety 10 fold. now you have to assemble a 2 sided cd, build another laser assembly, and find a way to mount it so you can reliably get these double sided disks in and out.

Having said all that, it would be a rather interesting project to undertake, though I have to imagine that unless you use alerady exsisting drives and modify them, building from scratch would be extremly difficult to say the least.

-Michael Moran

Lasers... which are a complex beast in and of itself

A 6502 computer for now.


Build another laser assembly?!?!?!? Are you nuts?!?!? Do you have any idea how hard that is? I will be using already existing laser assemblies. The circuit board will obviously have to be homebuilt?

Other than the laser assemblies everything will be home made.
Lyos Gemini Norezel

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CD-ROMs can be re-written only a few times, can't they? like less than ten times? (I'm not challenging-- I just don't know for sure.) Considering the amount of space, power, complexity, error-detection and -correction for even minor scratches, and other things a CD drive would require, I think you'd do much better to pursue flash memory, whether CompactFlash, MultiMedia Card, SecureData, even PCMCIA. These modules, some the size of a postage stamp, are already out to a gigabyte, and can be re-written 100,000 times or more. Their timing requirements are very simple and easy to meet, and the serial ones like SD and MMC can be interfaced with four wires.

I'm not sure... I will have to look this up.


Could this, with clever programming, be considered by the CPU as a hard drive? I had thoughts like this before but never got anywhere... I had originally wanted 20 terrabytes of RAM/ROM (ten terra of each) but realized soon thereafter that it could not be done. So I considered the idea of interfacing it though IDE and making the CPU recognize it as a hard drive. Is this feasable? Or am I insane?
Lyos Gemini Norezel

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> Could this, with clever programming, be considered by the CPU as a
> hard drive?

Sure, the system could recognize it as a hard disc drive. (The CPU doesn't care what you call it-- it only knows its instructions, registers, and what it sees as memory.)

> I had originally wanted 20 terrabytes of RAM/ROM (ten terra of each)
> but realized soon thereafter that it could not be done.

20TB is approximately as much as a thousand DVDs hold. I've heard of archiving a lot of data-- but 20TB?? If you played it back on your 6502 at 200,000 bytes per second, you'd have 28,000 hours of playback.

Maybe in another decade or two. Someone who thought he had a good idea asked me 20 years ago about doing digital recording (studio quality) and putting the data completely in memory, so you have no moving parts. I tried to explain to him why it was completely out of the question. Now 20 years later we're able to do it.

Cool.



Sweet... lol.


Who managed to do it? Was it the guy who's good idea you tried to squash? LOL.
Lyos Gemini Norezel

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BTW... if you tried to tell me it's impossible... I'd do just to be able to say "Who's the fool now?" LOL. And maybe even (if I was in a mean mood) say "Point and laugh at the idiot". Sorry but I can be mean sometimes. Especially when someone tells me something is impossible when I know it's not.
Lyos Gemini Norezel

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Who is this guy?

Let's try to keep discussions technical and avoid confrontation. Everyone has a valid opinion and we need to state these opinions in a positive and constructive manner.

If you would like to say anything that does not fit this criterion, please use the private message function to send an e-mail directly to the recipient without cluttering the forum.

Thank you,
Mike

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- Mike Naberezny (mike@naberezny.com) http://6502.org

Sorry Mike... I don't like it when people say an idea is impossible when I know it's not. I'll try to keep it off the forums.
Lyos Gemini Norezel
P.S.-I've always had a fiery temper... feel free to let me know if I get outa line.

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