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Why do DVD RW disks mostly have to be empty to write on?


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#1 zzzz

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Posted 24 July 2015 - 07:30 AM

If I have some files, back up or any other data on a virtually empty 4.7GB  disk, and I want to write on it, say, Partition Wizard (does it matter what the nature of the addition is?) then it can only be done on an empty disk.

 

I think if it contains only data then more data can be added but other certain 'media' cannot - is this right?

 

Why it cannot use the existing remaining space?



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#2 Chris Cosgrove

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Posted 24 July 2015 - 07:46 PM

They don't - but it depends on how you process them !

 

It doesn't matter if it is a re-writable disc or a write once disc, if it is 'closed' then you can write nothing more to it (RW types can of course be re-written). When you are writing to a disc look for an option either NOT to close it, or to use it 'like a USB drive'.

 

You will probably have noticed that when writing a disc there is a period when the drive light is flashing but no data is being transferred, this is the 'opening' data. And, if the disc is to be closed you will have have a similar period at the end, this is the 'closing' which prevents any more data being added. If you choose whichever of the options above (or some similar wording) applies, this closing won't happen and you will be able to add data to the disc up to its capacity limit.

 

Chris Cosgrove



#3 zzzz

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Posted 27 July 2015 - 06:25 AM

Thank you for your response.

 

I should have said that I use DVD RW disks as well as CD-R. I must say I have never noticed any option to close or not nor the usb option. Also as my drive bay is not in sight I don't see the light flashing either!  

 

If a disk R or RW has been closed from a previous operation is it possible to open it without affecting what is already on it? The only message I get is, 'This disk is not empty' , nothing about choosing to open it.

 

So the nature of the data, whether it is text or a program or whatever makes no difference if the disk is 'open'.



#4 Chris Cosgrove

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Posted 27 July 2015 - 11:12 AM

The exact wording varies from burning application to burning application. If you look at the image linked below this is taken from my 'quick and easy' burner. Clicking on the 'Options' button brings up the gray 'Options' box and you will see that the second line, which is ticked, reads 'Finalise disc (no further writing possible). If you untick this box then the disc will not be finalised (or closed) and you will be able to write more data to it at a later date.

 

https://www.dropbox.com/s/9x1effiizjsip8b/Finalise%20option%20switch.jpg?dl=0

 

If a disc of any sort is finalised or closed then you cannot write any more data to it without, for a RW disc, re-writing. But as far as I know, if you do not finalise or close the disc then you can write more data to it for all types of disc.

 

If a disc is still open it makes no difference what type of data you are writing. You could start with a bunch of Word documents, then add a handful of video clips and finish off on a third occasion with a set of accounts.

 

I hope this answers your questions. Since I use DVDs primarily for backing up and shipping photos around - I ship a lot of photos around - I have to admit that I have never actually done this, but I know the facility exists and the image is the proof !  Normally I am trying to get as close as possible to the 4.7 GB limit as I can without going over it.

 

Chris Cosgrove



#5 zzzz

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Posted 08 August 2015 - 05:51 PM

Thanks for your response.

 

Your link shows the finalise option and perhaps I also get this but never thought to read it! I just assumed one could add to a disk until full so I'll look out for it next time.



#6 jonuk76

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Posted 11 August 2015 - 09:01 AM

It's been a very long time since I used this (USB flash drives are a far better solution these days IMO) but I used to use something called packet writing software for CD-RW/DVD-RW discs.  Nero and Roxio have different versions of the software that are not directly compatible with each other (Nero's InCD was what I used to use, Roxio's Drag to Disc is an alternative).  There's probably other alternatives, but that is something to look into.

 

Basically the idea of this is that you use the software to "format" the optical disk in a special way (it's actually called Mount Rainier format, but you don't need to know that), and then it can be used exactly like a floppy disk or flash drive - files can be dragged and dropped, deleted, replaced etc.  If I recall correctly these specially formatted discs are readable on any other computer with a DVD drive with modern OS's (very old OS's may need additional software installed).

 

I just thought it sounded like the kind of thing you might be after, although like I said, it's a long time since I've used it myself and I don't know what the current software is like, and whether it works on the latest operating systems etc.


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#7 rp88

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Posted 13 August 2015 - 12:54 PM

"USB flash drives are a far better solution these days"


They are certainly quicker to write to and read from, can be fully overwritten and such but they are a little more vulnerable to certain types of damage than USB devices. Because CD and DVD discs are optical media they don't suffer the same kind of degradation that flash based memory can over time, and a more significant difference is that optical media will survive a CME (coronal mass ejection) or EMP (electromagnetic pulse) rather better. If you have important data it's a good idea to have atleast one copy on optical media, even though all the other copies might be on flash drives and hard-drives, because if anything happenes involving strong electromagnetic fields then the optical media will survive it a lot better. Also things on a CD or DVD disc can't generally be erased except by physically wrecking the disc, while data on a USB can be deleted in milliseconds. A final reason that optical media isn't totally obsolete is that, as long as there is no free space left to write anything to or as long ad the disc is put into a read only cd/dvd drive, then if you ever needed to copy files ONTO an infected machine, the infected machine couldn't infect the disc when you inserted it. I'm not trying to say CD and DVD discs are "better" than USB devices, but I am trying to say they still have uses.

Edited by rp88, 13 August 2015 - 12:55 PM.

Back on this site, for a while anyway, been so busy the last year.

My systems:2 laptops, intel i3 processors, windows 8.1 installed on the hard-drive and linux mint 17.3 MATE installed to USB

#8 jonuk76

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Posted 16 August 2015 - 05:51 PM

Yep they have their advantages and disadvantages.  Not all DVDR and CDR media are equal.  I've lost stuff from both after a few years, probably due to degradation of the dye layer on substandard discs.  Keeping them where they are exposed to strong sunlight is always a no no but these have always been kept in a black wallet.  And I have some discs which still work after 10 years+.


Edited by jonuk76, 16 August 2015 - 05:51 PM.

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