900mb CDs

I've not heard of a 900mb CD yet.
If you need to put 900Mb's on a normal 700Mb CD, some CD burning software will allow you to format the CD with a compression feature. I think Toast can do this.
Another option is to use a compression application like Stuffit Deluxe to get the file sizes down to a minimum.
Otherwise a DVD would be the next choice.

I use Toast extensively and am not aware of any facility to compress the contents of a CD. I just hunted through all the options and found nothing.

The nearest means to achieve this would be make an archive (gather all the material into a folder) then turn this into a compressed .dmg file using Disk Utility and burn the resulting .dmg onto a CD.

Depending on the content you may be able to achieve the 23% compression you are seeking. Just be aware that jpgs, MP3s and most pdfs won't compress much if at all because they are fully or mostly compressed already.

You're right Peter. It's not with CD's, but with DVD's.

http://www.roxio.com/en/company/news/archive/prelease08_2205.jhtml
Powerful DVD Compression: Compress and copy an entire 9 GB dual-layer DVD-Video to a standard 4.7 GB recordable DVD disc.
I still wouldn't recommend this for archiving jobs.
Software just changes too much/fast anymore.

Hi Peter,

You need to be using Toast 7 to have this option. Both CDs and DVDs can be compressed as long as you are using the "Mac Only" format when writing the disk. In that format, the options drawer will have a check box for "Compressed".

But to the original question, if you could even find them (I don't think they exist), I would not recommend using 900 MB CDs. Even 800 MB disks are risky to use. Most drives (especially those more than a few years old) can't read them. Attempting to write such disks with older drives can actually damage them. Stick to either 700 MB CDs or DVDs.

Thank you Kurt, I am running Toast 7 but never saw that because I always make my CD/DVDs bi-platform. Guess I am still nervous of Apple's long term chances. Anyway it pays to make sure precious work is available no matter what computer you are on.

I will have a look at it and see how well it works and what sort of compression it is actually applying. One hopes it is nothing proprietry and something like ZIP or RAR which would be a long term viable archive method. But you can never be too cautious, I would not have thought that Stuffit would slowly fade away as it has done.

There are other issues with compressed material. Depending how it is done it can mean even small damage to the media can render the whole disk unusable.

Also excellent advice about buying common media that works on common hardware. My motto is if you don't have 2 copies of the hardware or can buy another cheap quickly don't use any technology.

If it were not so rare and expensive I'd be backing up onto DVD RAM using the cartridges whch have extremely long life and security. Everything is a compromise, use cheap common media and make multiple copies stiored in widely separate locations to allow for fire or theft.

Vipir: The compression you are talking about is the lossy compression when converting or "Ripping" audio and video material and not data compression which is what Kurt has mentioned. This compression method is actually destroying part of the information in the original which can never be recovered.

The kind of compression Kurt is talking about is "Lossless" compression where the original can be restored from the compressed version.

Guess I am still nervous of Apple's long term chances.

I still was a little, until the Intel Macs came out. Now with Boot Camp to draw in the Windows users, I can see Apple easily grabbing a much larger market share over the next few years. That, and the iTunes/iPod combo have made Apple a valuable company in a pretty short amount of time.

Anyway it pays to make sure precious work is available no matter what computer you are on.

Yup, better safe than sorry. Hybrid disks are a great way to make sure either Macs or PCs can read them as native disks.

I will have a look at it and see how well it works and what sort of compression it is actually applying. One hopes it is nothing proprietry and something like ZIP or RAR which would be a long term viable archive method.

I've been tempted to try one myself. I'd like to see if it's just calling up Disk Utility's .dmg format, or if it's proprietary to Toast. The manual doesn't really say. This is all it says about a compressed disk:
To access a compressed disc:
1 Insert the disc into a drive.
The disc contains a single file containing the compressed contents of the disc.
2 Double-click the compressed file.
The file will decompress to the Desktop.

Wouldn't be hard to find out what it does without wasting a disk though, as long as you use a CD-RW or DVD-RW.

I would not have thought that Stuffit would slowly fade away as it has done.

Yes, they've been hanging themselves lately. It's a great tool since it can open just about any compression format out there, but it's greatest drawback is how incredibly slow it is creating its own .sit or .sitx format. From what I've read, it still doesn't have multi processor support or multi threading. They seriously need to revamp the code from the ground up to bring people back. Right now, OS X's built in .zip support is killing their sales what with how slow Stuffit is. The two main things keeping it going is the better compression rates in its own format and being able to open most others.

Depending how it is done it can mean even small damage to the media can render the whole disk unusable.

Yup, there is a certain amount of risk backing up a compressed file. About all you can do is do a verify after creating the .dmg file. Then after you burn the disk, do a verify of that.

I still was a little, until the Intel Macs came out. Now with Boot Camp to draw in the Windows users, I can see Apple easily grabbing a much larger market share over the next few years.

I am feeling a bit more comfortable too and am very pleased with my iMac G5 and awaiting keenly new Intel Mac Desktops and a 2nd generation Intel iMac and Mac mini.

But all said and done the glass is not half empty it is 3% full and not making much headway in marketshare, particularly in the faster growing international market.

All will hinge on how well Vista and Leopard shape up against each other and how much the growing ill-will against Microsoft affects their business. In the end it won't be Apple that wins, but Microsoft that loses marketshare.

Yes, they've [Alladin] been hanging themselves lately.

Alladin hasn't been just doing it lately this has been endemic. Even in OSX it hogs the processor's time and I am tired of the "Upgrades" that aren't.