Burning multi-session CDs in Panther

Due to a potential issue with multi-session CDs in Mac® OS X 10.3 Panther®, we've elected to separate the following information about multi-session CDs in Mac OS X from the body of our book, Troubleshooting Mac OS X, Second Edition, so that we could provide updated information as the situation evolves.

This page will be updated as new information becomes available.

This document addresses the following topics:

About multi-session CDs

In Mac OS X, multi-session CDs are actually multi-volume: when the CD mounts in Finder™ or the desktop, each session is mounted as an individual volume.

This differs from how third-party disc burning utilities, such as Charismac™ Discribe™ or Roxio® Toast®, treat mutli-session CDs. Third-party utilities treat a multi-session CD as one volume to which you can burn multiple times, adding data to the CD each time.

Historically, the reason for this difference seems to stem from the early days of CD, when the data-specific standards for such were still being debated. Apple® elected to treat multiple sessions as individual volumes and built their original disc recording framework accordingly. This design choice has been maintained up through the present version of Mac OS X.

Burning multi-session CDs in Jaguar

Burning "multi-session" CDs in Mac OS X 10.2 Jaguar is well-behaved. The instructions for doing so are in the AppleCare® Knowledge Base document "Mac OS X 10.2: How to burn a multi-session CD."

Burning multi-session CDs in Panther

Instructions for burning multi-session CDs in Mac OS X 10.3 Panther are provided in the AppleCare Knowledge Base document "Mac OS X 10.3 Help: Recording on a CD or DVD Disc More Than Once." This information is also available in Mac Help.

Reports on the Apple Discussions concerning burning multi-session CDs in Panther are a mixed bag:

  • Some users report no problems whatsoever.
  • Some users cannot get multi-session CDs burned in Panther to mount, or can only get the first session (volume) to mount in Finder or on the desktop.
  • Some have found it is necessary to restart their Macs after burning a multi-session CD to get the disc to mount properly.

Since the instructions appear to work for many, this leads one to suspect either a bug in Panther or some anomaly in the systems of users who are having problems with such. To date, we have not been able to ascertain a specific cause.

Obviously, for CDs, DVDs, and FireWire® devices -- such as an iPod® or FireWire hard drives -- to mount on the desktop in Panther, one must select CDs, DVDs and iPods in the Finder > Preferences > General tab.

Instructions for burning multi-session CDs in Panther

The following instructions are based on the Mac Help article cited above, with additional details provided for improved clarity.

Creating a multi-session CD in Panther consists of two primary steps:

  1. Creating a temporary disk image that will be burned as the session.
  2. Burning the temporary disk image as a new session to a CD.

The size of each session is equal to the size the temporary disk image. A CD burned in Finder will be a non-appendable, single-session CD.

The following instructions encompass both major steps.

  1. Create a new folder on your desktop. Assign a file name to the folder that will become the name for the volume corresponding to the session when mounted in Finder or on the desktop.
  2. Move or copy the files to include in the session into the folder created in step 1.
  3. Open Disk Utility.
  4. Select Images > New > Image from Folder...
  5. Navigate in the resulting Open dialog and select the folder created in step 1. Click Open.
  6. In the resulting Convert Image dialog, type a name for the temporary disk image in the Save As field.
  7. Click Save. Wait while the disk image is created.
  8. Select the temporary disk image you named in step 6 from the list of disks and volumes on the left side of the Disk Utility window.
  9. Click Burn in the Disk Utility toolbar, or select Images > Burn.
  10. Insert a CD when prompted. This can be a blank CD or a previously burned multi-session CD.
  11. Click the blue triangle in the upper-right corner of the Burn sheet to reveal more options.
  12. Select Leave disc appendable.
  13. Select an option as to how the CD will be handled after the burn: either Eject disc or Mount on Desktop.
  14. Select the Burn button or the Append button, the latter if the CD is a previously burned multi-session CD.
  15. After the burn completes, Quit (Command-Q) Disk Utility.
  16. Trash the temporary disk image created in step 7.
  17. Empty the Trash.

The future of multi-session CDs in Mac OS X

Speculation abounds that Apple will incorporate UDF packet writing in a future version of the discrecording framework, possibly in Mac OS X 10.4 Tiger. This would essentially enable one to use a CD-RW or DVD-RW disc like a removable hard drive, reading or writing randomly to such. The advent of high-speed disc burners, combined with caching, may also provide adequate speed for this to be practical. Additional information on UDF packet writing can be found in the "Related links" section of this document.

Related links

The following links provide additional information on UDF and packet writing.
Did you find this FAQ helpful? You will find a wealth of additional advice for preventing or resolving Mac OS X problems in Dr. Smoke's book, Troubleshooting Mac® OS X.
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