> Attaching 2 or more computers to one drive won't physically hurt the > firewire interface but it may corrupt the drive. Each computer will mount > the drive and there is nothing to keep them from writing contradictory > directory information to the disk. So don't do it.
The IBM System/360 and its follow-ons could attach a single drive to up to eight independent CPUs, but this was supported by special software within each OS and with special commands within the drives. Basically, one processor would issue a "reserve" command to the drive, thereby preventing any other processor from accessing that drive. After all operations by the reserving processor had completed, that processor would issue a "release" command to the drive and other processors could then access the drive. Once "reserved", all other processors would see "busy" status on the drive until it was "released". Later, it became possible to lock-out data on a track-by-track basis, or on a range of tracks. This technique facilitated making "live" backups of drives which were also undergoing updates, whereby the drive would indeed be updated in real-time, but the tape backup would always contain the most recent snap-shot of the entire drive. Much later, this backup concept was extended to backups which were made to remote data centers, located perhaps thousands or even tens of thousands of miles remotely from the primary site. Micros (and minis) are nowhere near as smart in their data management and data protection schemes as are mainframes, which is probably why mainframes continue to process most "enterprise" data. -- You received this message because you are a member of G-Group, a group for those using G3, G4, and G5 desktop Macs - with a particular focus on Power Macs. The list FAQ is at http://lowendmac.com/lists/g-list.shtml and our netiquette guide is at http://www.lowendmac.com/lists/netiquette.shtml To post to this group, send email to g3-5-list@googlegroups.com For more options, visit this group at http://groups.google.com/group/g3-5-list
