CPRM is designed to restrict the movement of digital files (which could be content or executables) according to rights set by the copyright owner, rather than the computer users, and it presents a formidable obstacle to crackers.
The CPRM-protected Secure Digital format grabbed 30 per cent of the US flash memory market in October, overtaking Compact Flash for the first time. CF took 28.8 per cent share and Sony's Memory Stick formats 22 per cent, according to the market research firm NPD Group. Although technically antiquated, CF still enjoys economies of scale from its long leadership, with 1 GB cards retailing for about $400.
CPRM was developed at IBM's Almaden Lab with support from Intel and the largest two manufacturers behind SD, Matsushita and Toshiba.
Support for CPRM found its way into the SCSI standard, and was being handled by the ATA standards body T.13 at the sub-committee level responsible for removable media. However, the first time that most people heard of it was when moves to incorporate CPRM into the full ATA specification used by fixed hard drives came to light. Those proposals, and a resulting compromise - which may have permitted CPRM-like DRM schemes, but flushed them out into the open - were eventually defeated.
In addition to raising awareness of share-denial technology and the value of open computing platforms, the episode probably had two lasting consequences.
Firstly, it pushed disk-based DRM 'underground'. Hard disk manufacturers use private proprietary commands and the T.13 ATA committee simply tries to ratify a common subset. DRM schemes today use private commands. Secondly, the defeat of CPRM on ATA probably swung the copyright owners' behind lock-down TCPA architectures as the solution to 'piracy'. Although TCPA advocates plead the Wernher von Braun defense ("The rockets go up…") it's incontestable that a 'trusted system' such as Microsoft's Next Generation Secure Computing Base (NGSCB aka Palladium) can prevent system level hacks which defeat copying restrictions. ®
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Our CPRM on ATA FAQ