Date: Mon, 30 Aug 2004 18:19:48 -0300 From: Fernan Aguero <fernan@iib.unsam.edu.ar> To: Wojciech Puchar <wojtek@tensor.3miasto.net> Cc: FreeBSD Questions <freebsd-questions@freebsd.org> Subject: Re: maximum hard drive capacity supported? Message-ID: <20040830211948.GK464@iib.unsam.edu.ar> In-Reply-To: <20040830223906.Y15234@chylonia.3miasto.net> References: <20040830141749.GA534@iib.unsam.edu.ar> <20040830223906.Y15234@chylonia.3miasto.net>
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+----[ Wojciech Puchar <wojtek@tensor.3miasto.net> (30.Aug.2004 17:55): | | > | > Upon trying to buy a new hard drive (80 GB) I was asked | > about the capabilities of my system, and I just thought that | > these were needed to tell what kind the IDE (ATA) | > capabilities. However, the vendor said that depending on the | > BIOS the system might not be able to recognize a large disk. | | BIOS is only needed to boot. | FreeBSD then drives it without BIOS Thanks for pointing this ... that's what I originally thought! | there are 3 possibilities: | | 1) BIOS just supports whole drive. nothing special needed | | 2) BIOS can't support the whole drive, it detects as much smaller one. actually, from what I've read there are other possibilities. I'm providing two URLs that seem to say essentially the same thing: http://storagereview.com/guide2000/ref/hdd/bios/sizeHandling.html See section How a BIOS handles Oversized Hard Disks in: http://www.dewassoc.com/kbase/hard_drives/hard_drive_size_barriers.htm | solution: | | install system with separate /boot partition that fits in the range that | BIOS supports. after booting FreeBSD will get whole disk OK, that's what I remember reading when I first installed FreeBSD ... but that was a long time ago. This is the disadvantage of using an OS you don't need to reinstall :) Now, in my case I don't need the new and bigger disk to be the bootable disk (i.e. I already have two drives that are sliced, partitioned and working fine). I just need it to be another disk to hold a /home or /scratch partition ... so does it really matter what the BIOS sees? | 3) BIOS hangs completely trying to drive your disk. | rare case but i have this with P133 machine with 80GB disk. OK, in this case it might matter. But I also read it is rare. Perhaps it's also less probable to happen if the big disk is not bootable (i.e. does not contain a MBR)? (I'm not knowledgeable enough on this issue, so perhaps it does not matter whether it has an MBR or not ...) | machine runs NetBSD, and i boot kernel from floppy, then NetBSD supports | whole drive. | | with FreeBSD it could be difficult to fit kernel on floppy but it is | possible if you will compile yours with minimal set of drivers (but | including disk) and then load modules from disk by startup scripts. | | my custom kernel compresses to 977000 bytes, loader takes 237568 bytes so | it could fit. | unfortunately i don't have enough FreeBSD knowledge now to tell you how | prepare such floppy. | +----] Let's hope I'm not in this situation ... my custom kernel (2.6 MB) compresses to 1214598 bytes. Thanks for your reply! Fernan -- Fernan Aguero - fernan at iib.unsam.edu.ar Phone: +54 11 4580-7255/7 ext 310, Fax: +54 11 4752-9639 Check http://genoma.unsam.edu.ar/~fernan for more info.
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