On Sat, 23 Mar 2002 16:38:01 -0800 Bill Campbell <[EMAIL PROTECTED]> wrote:
> On Sat, Mar 23, 2002 at 04:00:09PM -0800, Net Llama wrote: > >Mike, what pain in the ass are you referring to here?? > > My guess would be the assignment of device names. Generally they're > assigned in order of SCSI-ID and host adapter. The first SCSI hard drive > found is /dev/sda1, second, /dev/sda2, etc. The time this can be a severe > pain is if one has installed a primary hard drive using the default > settings from the vendor (often SCSI-ID=6 since they supply two jumpers), > and a new drive is installed with a lower ID. The assignment order is part of the SCSI standard. In fact, the logcial device numbers(s), LUN number(s) and SCSI ID number(s) are all ordered per the standard. Software that does not follow the standard will ultimately fail.... Now that I think about it (It's been awhile since I did low level SCSI work), even the timing of the physical bus/device must be within certain boundries as defined by the standard. Each standard has it's own definitions (SCSI-1, SCSI-2, SCSI-3 and etc...). >It helps to have a systematic plan when setting up SCSI devices. Being an old >SCO >hand, I tend to put the tape no ID=2 and CD on ID=5 because that was their >standard >starting on my first Tandy 4000 386-16 running Xenix. Bill is right: The best keep good notes or query the bus before installing a new device so you can assign a free ID to the device. It's the only way to do it. Personally, I use soft links to all devices with the exception of hard drives. So, all of my tapes, scanners, cdrw's, cdroms and ect are soft linked... I do this for security reasons. A good analogy is: SCSI is a stone castle built on a solid foundation. The foundation is based on a set of rules that allow for great expandibility and movement of huge amounts of data (I can get 14 devices on my adaptec card). These rules insist on careful thought on the part of the administrator. On the other hand, IDE is a lean-to, built of wood and anything else you can find. Take a huge system load, put it on scsi bus and an IDE bus... The SCSI bus handles everthing as advertised and the IDE bus collapses from the weight. In my opinion, after memory upgrades, a good scsi card and devices are the best investment a user can make. The performance gains are *always* there. Best Peck _______________________________________________ Linux-users mailing list - http://linux-sxs.org/mailman/listinfo/linux-users Subscribe/Unsubscribe info, Archives,and Digests are located at the above URL.
