Date: Tue, 06 Aug 1996 09:10:15 -0400 From: Gary Chrysler <tcg@ime.net> To: Chuck Robey <chuckr@glue.umd.edu> Cc: Annelise Anderson <andrsn@andrsn.stanford.edu>, Steve Marmer <ids@interlog.com>, questions@FreeBSD.org Subject: Re: Panic mounting root Message-ID: <32074437.67E@ime.net> References: <Pine.OSF.3.95.960805131945.11075C-100000@ginger.eng.umd.edu>
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Chuck Robey wrote: > > On Mon, 5 Aug 1996, Annelise Anderson wrote: > > > On Mon, 5 Aug 1996, Gary Chrysler wrote: > > > > > Steve Marmer wrote: > > > > > > > > I get a panic on boot, after all the hardware stuff, about the inability > > > > to mount root. > > > > > > > > Hardware: 4G Quantum Atlas FastWide Scsi-2 > > > > AHA1542CF FAST SCSI-2 > > > > (using a 6?-50 pin adapter) > > > > > > > > I have enabled the AHA1542 option "Translate Drives >1G". Since newfs > > > > worked I assume the problems with this have been fixed. My disk starts > > > > with a 950Meg DOS partition (slice). The next "slice" is 1G FreeBSD. > > > > I've been pretty careful ensuring the root part'n is fully below the > > > > magic 1G boundary. Have I not been careful enough? Could something else > > > > be the problem? > > > > > > > > Thanks for any and all help... > > > > > > Not to start a war! I know some dissagree! > > > > > > But bootable partitions *must* be under cylinder 1024. (504M) > > > This is a limitation of the PC System BIOS boot code! > > > > I think this refers only to IDE/EIDE drives. I have a 2.1G Conner > > fast scsi 2 installed as a second hard drive on an Adaptec 1542CF, > > and FreeBSD is running in the *last* 660 mb. on that drive (booting > > from the OS/2 boot manager). > > Actually, it applies to both, but scsi drives all support more flexible > remapping of sectors to make them all fit under 1024 cylinders, so they > don't feel the pinch. BTW, the whole partition DOES NOT have to be under > 1024 cylinders, just the boot sector of that partition. > Chuck, While we're on the subject I'd like to clear this up in my mind. A FreeBSD slice is: Sections of a partition?? So properly stated: Only the root slice needs to be under 1024. (If needed :) Is that about how it works.. I never fully understood the slice. The need to fully understand hasn't came upon me yet.. :) I'm not a SCSI guru, But it is my understanding that SCSI's access in a LBA method. ie: c:0 h:0 s:0 = LBA 0 c:0 h:0 s:1 = LBA 1 etc ... etc ... It is also my understanding that most OS's (Advanced OS's) also use a LBA method. So if your drive uses CHS, The bios has to translate OS calls to/from CHS to write/read. But like I said, I'm no guru on the internals of disk IO. I welcome the knowledge though. -Enjoy Gary ~~~~~~~~~~~~~~~~ Improve America's Knowledge... Share yours The Borg... Where minds meet (207) 929-3848
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