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Thread ID: 24154	2002-09-04 11:48:00	Rewrite again to CD-R works	E.ric (351)	Press F1

Post ID	Timestamp	Content	User
76426	2002-09-04 11:48:00	Now I was on the understanding that one could write to a CR-RW as many times as you like (at least 1000), and to a CD-R only once, But tonight I run "HTML Tidy" on my HTML file I wrote and it deleted part of the information, before I noticed the missing data , I burnt the file to a CD-R. But I was able to save the same file again and get back the missing data, So now I take it, when you write the same file name to a CD-R again, the writer destroys that part of the CD that holds that file and puts the updated file in some other empty space on the CD.	E.ric (351)
76427	2002-09-04 12:30:00	Wooo ... I'm gonna try that one now :). Stay tuned.	helvista (1745)
76428	2002-09-04 12:43:00	Lemme get this right. You had file X. You burned file X to CD-R. You took something away from file X. You burned file X to same CD-R You took file X off CD-R to find original file intact. Does it not follow that the modified version never got burned at all?	SoniKalien (792)
76429	2002-09-04 12:58:00	Also the "old" file does not get "destroyed" The TOC just doesnt point to it anymore, but its on there...(BTW its a whole new TOC as well)	godfather (25)
76430	2002-09-04 13:34:00	Well, that was an interesting lil experiment. I did as you suggested and it worked. I placed an unused CD-R (DataLife, 700MB) into my CD burner. I copied a directory onto the blank CD-R and checked the content of the CD to make sure that it copied correctly. I then added a text file to the same directory on my hard drive and copied the updated directory to the same CD-R. As you suggested it wrote to the CD-R, no complaints. I checked the contents of the CD and it had updated the directory correctly (it had the new text file I added). But then I decided to copy over a new directory ... different name, size and location to the same CD-R. Now this is what amazed me ... it wrote to the CD-R without any complaints. I checked the CD's content and it displayed the old directory. I ejected the CD and closed the CD drive door (whatever its called), with the same CD-R in it, and checked the contents again. The old directory was gone and the new directory I copied over was now displayed .. it seems it had copied the directory over correctly. I just had to open & close the CD drive door for the contents to be displayed correctly. I thought maybe this was a unique characteristic of DataLife CD-R so I repeated the above process but this time with an already used Elite DATA 700 MB CD-R. Nero did complain and asked me if I wanted to finalise the CD. When I cancelled Nero proceeded to write to the CD-R. As before I had to open and close the CD drive door in order for the new contents to be displayed. I am absolutely baffled as to why this is since I was told & read that one can only write to a CD-R only once. If I had not read your post I would not have even thought of testing it out to determine the validity of what I was told ... I feel like such a monkey, monkey see monkey do. Good spotting!	helvista (1745)
76431	2002-09-04 19:01:00	> Lemme get this right. > You had file X. > You burned file X to CD-R. > You took something away from file X. > You burned file X to same CD-R > You took file X off CD-R to find original file > intact. > Does it not follow that the modified version never > got burned at all? No no no no I saved a file to CD-R, then I found, #$%^ it saved OK but not what I hoped to save, So I fixed the error on my hard drive copy and saved it again, and :) just how I liked it.	E.ric (351)
76432	2002-09-04 21:49:00	Correct. it is possible to right to a CDR more than once. My Uncle copies photos to his CDs and then finds more and adds them as well. This can sometimes be a task to do, but once you know how to do it it is easy. If you are wondering how to do this though you will have to figure it out yourself. I am useless at explainning things and this is quite a complicated thing to do. At least I found it was. :)	NathanTheKind (472)
76433	2002-09-04 22:48:00	Hi there When you completed all your tests, did the remaining space on the CD show that the sum of all writes had been used, or just the size of the last file/directory written? For example, if you wrote a 250MB file then modified the original by changing say a 50MB file and rewrote it, would the CD then show 300MB used and 350MB free (assuming it had 650MB to start with) or would it still show 250MB used and 400MB free. If the former then a new TOC is probably being written pointing to the new entry, and if the latter, you would be rewriting the original file space which I always understood to be write-once only as an absolute, hence the piles of coasters people accumulate. I hasten to add that I am theorising here as I do not have a CD writer myself, however the concept intrigued me. Assuming that a CD-R cannot be rewritten over an area that had been burned (and I'd be very surprised if it could) an absolute "write once" constraint would suggest that the TOC can't be modified or a new one written, while E.Ric's experience would seem to suggest that a new TOC can be written with the location of the modified file recorded along with the locations for the original files. The old TOC would become inaccessible. But then, I could be wrong. :8} Cheers Billy 8-{) ?:|	Billy T (70)
76434	2002-09-05 01:44:00	Hmmm .... interesting ...... I think this is what is probably happening: Session 1: Files 2meg.txt, 200meg.bmp, 10meg.gif, & 35meg.jpg get written to the root folder of a blank cdr. Session TOC written and closed. Total file size = 2 + 200 + 10 + 35 = 247Mb. Total space used = 247Mb. Total space remaining = 650 - 247 = 403meg. CD stays in tray, 2meg.txt is altered in size to 50meg Session 2: Files 2meg.txt (now 50Mb), 200meg.bmp, 10meg.gif, & 35meg.jpg get written to the root folder of the existing cdr. Session TOC written and closed. Total file size = 50 + 200 + 10 + 35 = 295Mb. Total space used = 247 + 295 = 542Mb. Total space remaining = 650 - 542 = 108Mb. CD stays in tray. Attempt to access 2meg.txt, you get the copy from session 1 because session 1's TOC is cached by Windows so it will point to the earlier portion of the cd, but take the cd out of the tray and reinsert it and you will get the larger copy of 2meg.txt because the TOC has been flushed from Window's cache, and you are accessing the TOC physically from the CD.	antmannz (28)
76435	2002-09-05 01:52:00	If you don't finalize the cd-r, of course you can add more, until the disc is full. Or am I missing something. Bye	Peter H (220)
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