Its not possible to access the GRUB command line until stage 2 loads. The CLI lives in stage 2. ----- Original Message ----- From: "Ken Teh" <[log in to unmask]> To: "John Summerfield" <[log in to unmask]> Cc: "Scientific Linux" <[log in to unmask]> Sent: Tuesday, January 08, 2008 11:44 AM Subject: Re: grub hangs with attached scsi disk > John Summerfield wrote: >> Troy Dawson wrote: >>> Ken Teh wrote: >>>> I just installed a 4.5 machine and it hangs when booting at "grub >>>> loading stage 2". Here's the strange part. It hangs only when a SCSI >>>> disk (LVD/SE) disk is attached. SCSI card is an Adaptec 29160. When >>>> the disk is removed, it rips right through the boot. The disk is fine >>>> because I use the 4.5 install disk in rescue mode and I can see the >>>> disk, mount it, and all its data is there. I tried with another disk >>>> and I have the exact same result. I'm baffled!! >>>> >>>> Ken >>> >>> The odd's are that it's because the disks are getting re-ordered when >>> you plug in and unplug the scsi disks. >>> >>> Without any disks there, grub is saying "here is my disk on (hd0,0) and >>> away I go" And since hd0,0 is the right disk, away it goes. >>> >>> With the other disks there grub is saying "Well, I have two disks, >>> (hd0,0) and (hd1,0). I'm told I need to boot off (hd0,0) and away I go" >>> But, in reality, your main system disk is what grub thinks is (hd1,0) >>> and so it's booting off the wrong disk. >> >> Ken, you can test this by getting to the grub command line and typing >> stuff like >> help >> root (hd0,0) >> root (hd1,0) >> find >> >> etc etc >> >> > > Thanks to John and Troy who responded. Unfortunately, I was not able to > resolve it. I've reinstalled grub after specifying grub's root. When I > do this, it hangs at stage 1.5 instead of 2. I've verified it's the > correct root by 'finding' the stage# files. I've tried fixing the order > after reprobing and then editing the device.map file. I've disabled SCSI > boot from the BIOS and verified that the BIOS boot order corresponds to > the device.map order. I've even tried installing the machine without the > SCSI card so that the SL installer does not load the AIC7xxx driver. All > to no avail. I'm pretty sure it's something in grub. The system was > running SL3.x with an IDE system disk and this external SCSI drive. All I > did was reinstall it with SL4.5. > > Do you know if it's possible to get to the grub console at bootup but > before it loads stage 1.5 or stage 2? If it is reordering, then I need a > "live" (or in this case, "dead") system to verify instead of booting > succesfully via linux rescue, then grubbing the system. >