I was under the impression these were RK03s. Now I understand they are indeed RK01s. -- DEC never sold Pertec drives, though lots of third parties did. They most often showed up as Plesey add-ons. What you probably have is some variant of the D4000. They came as fixed/removable, just removable, 2315 front-load or 5440 top-load packs. The 2315 flavor was compatible to RK05's, 5440's were 5mb. Just checked, I have the D4000 service manual scanned, but it isn't up on bitsavers. I'll see about getting that done.