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Number of Discs Changes



Bear with me as I give you some background to this issue.... Ok, so I've taken about 45GB worth of iDVD files and used BetterZip to back them up to 71 RAR files of 626 MiB (binary, base-2) split volumes.


From my calculations, 626 MiB (or 656,408,576 bytes) is the greatest common factor for all major recordable optical media now-a-days. That means that the chunks (compressed split volume RAR files) of data are small enough to fit 1 volume on a CD-R, 7 on a DVD, 13 on a DVD DL, 38 on a BD-R, and 76 on a BD-R DL. And yes, that does take into account the differences between MiB (binary, base-2) and MB (decimal, base-10)... and the subtle differences between various flavors of formats, like the capacity difference between DVD-R and DVD+R, etc. So I *think* 626 MiB is the optimal segment / split volume size for versatility in optical burning backups.


However, when I open and use Toast 9 to setup a Mac & PC data disc, I can drag 65 of my 71 RAR split volume files to the toast window. I switch the meter to calculate DVD DL and it says it will need 5 discs with about 39 MB free space remaining on the last disc, which is perfectly fine. (The reason I didn't add all 71 RAR files is because the last 6 volumes can fit on a standard single-layer DVD-R, so I'm not wasting space / money burning a dual layer for the last 6 files)


Here's the rub of all this explanation (thanks for bearing with me)... when I hit the big red burn button, Toast informs me that the burn will need 6 discs.... 6???? Why all of a sudden 6? The main screen before I hit the burn button just said it would occupy 5 discs with some MB's to spare.


Am I missing something here? Mathematically, it should only take 5 DL DVD's to backup 65, 626 MiB files with several MB of wiggle room left over on each disc. Why does Toast add an extra disc after I hit burn?


Maybe there is some capacity that's being eaten up by the UDF formatting (or whatever format it is using)??? If so, how much space does the formatting take up on various discs types / capacities? I may need to re-calculate my magic 626 MiB number a little less to account for that factor.


Thanks for your help guys.

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Wow... no replies what-so-ever? Did I stump everybody? Geeezzz.

Well, it was Sunday and I don't this for a living (although it seems like it at times). There probably are fewer than a half dozen folks answering posts in the Roxio Mac-product forums so if I can recruit you....


As for the issue, I haven't heard that come up before and I don't know why it would change to needing six DL DVDs. I suggest trashing the Toast plist and prefs files in your User>Library>Preferences folder because when those get corrupted Toast gets confused about how much can fit on a disc. Let me know if that makes any difference. In the meanwhile I'll ponder longer about what could cause this to happen.


Also, you can choose DVD-Rom (UDF) as the format instead of Mac & PC to see if that makes a difference.

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