Cd-R or Cd-RW?

isofa

CD-R/RWs do have a shelf life, and the dyes used do not last as long as people think. CD-RWs are more unstable that CD-Rs. Leave in the sun, and they'll degrade rapidly. Use some type of labels and the chemical will ingress into the plastic and damage the data. Pressed CDs (such as commercial music CDs) don't suffer from dye problems as they are pressed with permanent "pits", similar to a vinyl record.

If you have very precious data written on CD-R/Ws and DVD-R/Ws, without any other backup, it's prudent to read it in once a year or two and rewrite it to a new disc.

I use a combination for backups, DVD-Rs, DVD-RWs, several external hard discs, a large and fast memory stick, over USB2.0 it's very quick.

As for speed, if you buy a good quality USB memory stick (obviously USB 2.0), they are very fast. For example the PNY Attache Pro - 4Gb - takes only 58 seconds to write 1Gb worth of files, that'll be quicker than writing a 650Mb CD on any CD burners!

loveandlight would be much better off storing these spreadsheets on a memory stick (USB 2) for instant access and then burning to CDs for a backup every now and then.

When you burn to a CD and then copy back files from it to a PC, the files will be read-only, so you'll need to change the file attributes (right click, properties and uncheck read-only in the attributes section.)

free4440273

albertross wrote: »

Pull a usb flash drive out too quickly, and it is very easy to corrupt. If that is your only copy, your work is gone.

albertross is indeed correct: and always (it's good practice) click on the Safely Remove Hardware icon before physically unplugging the drive.

Reggie_Rebel

With CD-RW's or DVD-RW's you run the risk of accidently erasing your data.

All forms of back-up have their downfalls, for really essential data you should back-up to more than one source

superscaper

Reggie_Rebel wrote: »

With CD-RW's or DVD-RW's you run the risk of accidently erasing your data.

All forms of back-up have their downfalls, for really essential data you should back-up to more than one source

Absolutely. Diversity is the key. You shouldn't rely on one method and one form/medium of backup.

As for flash memory, although the technology has got better if you were to just leave it somewhere, it would over time lose its data (it may take quite a long time with decent flash memory but it shouldn't be 100% relied upon for permanent storage). It is after all an eletronic form of storage not a physical form such as CD/DVD.

squirrelz

loveandlight wrote: »

I want to be able to save some cash spreadsheets to disc and then add to the figures and make amendments as and when. I thought I needed to use a Cd-RW but someone in Currys said a Cd-R would do and someone in Mapplins said a Cd-RW. I tried using a Cd-R tonight but it keeps saying it is a read only file. So does this mean I should go out and buy Cd-RW's instead?
Thanks.

Neither CD-R nor CD-RW will really do what you are asking. You cannot update the file (ie. open it in Excel and save changes), you would have to have a copy on the hard drive, and use Nero (or whatever you normally use to write to CDs) to copy the updated version to the CD.

The only CD type way of doing this would be to use DVD-RAM, which works more like a hard disk.

superscaper

squirrelz wrote: »

Neither CD-R nor CD-RW will really do what you are asking. You cannot update the file (ie. open it in Excel and save changes), you would have to have a copy on the hard drive, and use Nero (or whatever you normally use to write to CDs) to copy the updated version to the CD.

Not strictly true. It depends on how you format it to begin with (for RW discs). If you use Nero's InCD for example and format the RW first then it's perfectly possible to edit files on the disc and treat it "as if it were a floppy disk".

Stephen_Leak

I fully accept isofa and Reggie's points about CD-RWs. If and when one of mine won't record, I will simply break out a new one. If I keep to my routine, my data is on the PC and two discs, and the discs are no more than a month "out of date". If the worst happens and my "onsite" backup won't work, I still have my "offsite" one.

The only "weak spot" is when a CD-RW is being erased and re-recording the new data, when this drops down to the PC and just one disc, which is either one month old or up to date. And there is still the "fire and flood" risk, until I take one disc back to work the next morning, but I think my regime covers most reasonable eventualities.

superscaper

Stephen_Leak wrote: »

The only "weak spot" is when a CD-RW is being erased and re-recording the new data, when this drops down to the PC and just one disc, which is either one month old or up to date. There is still the "fire and flood" risk, until I take one disc back to work the next morning, but I think my regime covers most reasonable eventualities.

I think I mentioned this in the sticky, that it may be worth considering offsite backup as well, whether this is just leaving a copy of a CD with granny or using online backup. I think I give estimates for backup frequency as well depending on what you're backing up, so ideally you should be minimising the loss of data depending on what goes wrong.

squirrelz

superscaper wrote: »

Not strictly true. It depends on how you format it to begin with (for RW discs). If you use Nero's InCD for example and format the RW first then it's perfectly possible to edit files on the disc and treat it "as if it were a floppy disk".

That's not strictly true either, all it does is mark the old one as deleted and write a new copy with a new file table. eventually you run out of space and have to format the disk.

superscaper

squirrelz wrote: »

That's not strictly true either, all it does is mark the old one as deleted and write a new copy with a new file table. eventually you run out of space and have to format the disk.

Hmm, I just tried it and after I edited the files directly from CD, the free space and space used was consistent with the two files I had put on. I also merely deleted the files and I regained all the space they were taking up without reformatting.