I'm making a TrueCrypt volume and want it to fit the entire available space on a 700MB, ISO formatted, CD-RW disc without overburning.

  • 1
    Owing to the nature of the medium, there is no exact maximum size. The same goes for any physical storage medium (including hard drives). So going for at least 700MB in the manufacturing process is probably how they do it. That's where I'd put my flag in the ground anyway.
    – user3463
    Commented Apr 8, 2011 at 3:39
  • 1
    I finally done it. The answer is 719320 kB that is rough 702.4 MB. Adding 1 kB more causes the recorder to go in overburn mode which is dangerous with CD-RW. (I've deleted my irrelevant comments of my rough estimation, this is exact value).
    – rsk82
    Commented Apr 8, 2011 at 11:53
  • 2
    That's fine for that particular batch of discs. Different ones may have different limits.
    – afrazier
    Commented Jan 29, 2012 at 13:37

2 Answers 2


You need to check how many free blocks are there on particular media. Then you make ISO of respective size.

cdrecord dev=/dev/sr0 -atip
ATIP info from disk:
  ATIP start of lead in:  -11077 (97:34/23)
  ATIP start of lead out: 359849 (79:59/74)
Manufacturer: Mitsubishi Chemical Corporation

My CD-RW has 359849 2k-sized blocks totalling 736,970,752 of data 32k+32k+3x2k will be used for ISO9660 service information. If you add joliet rockridge and hfs naming extensions it will be even more space wasted.

the "standard" limitation is for 640MB disks with many older drives not reading bigger disks, for 700MB it is more flexible.

In theory there is a lead-out are of size of lead-in after the end of programmable area which can be written with data fully and safely, but CD readers will be more likely to reject drive which does not have proper "session end" and lead-out marks.


The ISO specification imposes a limit of 2GB for a single file.

So for a CDROM the maximum size will be the size of the CD - 700MB (less a little for lead-in, lead-out and file tables)

For bigger file sizes the UDF system is preferred.

  • @user43300 i remember when i would back up DVDs to CD i used to be able to fit around 706 MB on a disc (no overburning). i never checked the actual size of the files on the disc in KB though.
    – Xantec
    Commented Apr 7, 2011 at 22:34
  • was it cd-r or cd-rw ?
    – rsk82
    Commented Apr 8, 2011 at 6:09

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