Cactus Data Shield
form of CD/DVD copy protection
Cactus Data Shield (CDS) is a form of CD/DVD copy protection for audio compact discs developed by Israeli company Midbar Technologies. It has been used extensively by EMI (subsequently acquired by Sony Music), BMG and their subsidiaries. CDS relies on two components: Erroneous Disc Navigation and Data Corruption.
As of September 2006, all of Macrovision's CD copy protection products, including CDS, had quietly disappeared from their website. The December 2006 issue of Billboard announced that EMI had decided to abandon Copy Control worldwide.
History
Erroneous Disc Navigation
CDS discs contain an initial audio session, similar to that of an unprotected disc. In addition the disc contains a second (data) session and a software player configured for auto-play with a lower-quality, compressed version of the audio for it to play.
The second session on the disc causes some CD/DVD players to hang, typically some car players (allegedly using CD-ROM drive mechanisms) and some MP3 capable players that can see but not understand the second data session.
The second session has been circumvented by another method, which is to either place masking tape around the disc near the edge, or mark a strip next to the edge with permanent marker. Because it is a multi-session disc, this method will hide the second session, leaving only the first audio session visible.
Begin with the source’s own compact description: “Cactus Data Shield” is form of CD/DVD copy protection. The dossier treats that line as a proposition to test through Cactus, Data and Shield, not as a finished interpretation.
Why this record matters
The phrase “form of CD/DVD copy protection” supplies a clear boundary for inquiry. It also exposes the unanswered questions: who defined that boundary, when it became stable and which sources sit outside it.
Vocabulary and entity names are the principal evidence signals here, because they determine the precision of every later search. The source revision retrieved here is dated Jul 12, 2026. The linked authority identifier is Q4020610. 1 of 1 selected statements include explicit references; 0 carry qualifiers and 0 use preferred rank. The first chronological checks are 2006.
The absence of detail may reflect summary conventions rather than a lack of surviving documentation. The lead is largely declarative, so disagreement and counter-evidence require a deliberate search beyond the opening account. Authority statements aid reconciliation but still require their own references, qualifiers and ranks to be checked.
How to read it
Use the entry as an orientation point, then follow its citations and revision history. Names, dates and institutional relationships should be checked against the original record.
- Subject orientation
- Search vocabulary
- Locating named sources
The closest primary source, responsible institution and strongest cited specialist reference.
Three-step research path
- Establish the record: confirm the title “Cactus Data Shield”, its source revision and the description used here.
- Expand the search: follow Cactus Data Shield primary sources, Cactus Data Shield archive and Cactus research across catalogues and specialist indexes.
- Test the account: compare the strongest cited source with the responsible institution’s current record and note any disagreement.
Questions for further research
- Which source most directly establishes the central claim about “Cactus Data Shield”?
- Which cited source is closest to the event, object or claim?
- What terminology or title could unlock a more precise catalogue search?
Search terms from this dossier
This entry incorporates text from “Cactus Data Shield” on English Wikipedia. Contributors are listed in the page history. Text is available under the Creative Commons Attribution-ShareAlike 4.0 License. Selected authority identifiers and statements are retrieved from Wikidata under CC0; their references and qualifiers remain part of the verification path.