[octorian]

I think the whole 512 byte sector CD-ROM thing was common to all the 90's-era "Real UNIX" machines. They generally all wanted to treat CDs like a hard drive, for booting purposes. (PCs, on the other hand, did a different weird hack where they'd embed a floppy image at the state of the CD and the BIOS knew how to handle that.)

[linksnapzz]

AFAIK, the "El Torito" standard, so named for the restaurant where ppl. from IBM & Phoenix BIOS hashed out how to do it...

[puzzle]

Yeah, you're right, they wanted 512 instead of 2048 bytes per sector to use the CD as a HD. But I think that at least one of the Unix vendors shipped the install media as 520 byte sectors, with 512 bytes of data and 8 bytes of checksum. In order to duplicate the discs, you needed to own a writer that was fancier than average (i.e. a SCSI unit, not an IDE one).

[__d]

I keep a DEC RRD-40 drive (with its weird pre-caddy disc holder thing) around for the purpose of booting old DECstations. Not sure if it used 520B sectors though. I think I have the manual .. somewhere.