Date: Sat, 28 Mar 1998 13:25:33 +1100 From: Bruce Evans <bde@zeta.org.au> To: bob@wbs.net, jkh@time.cdrom.com Cc: freebsd-hardware@FreeBSD.ORG Subject: Re: 12.0 GB Quantum Bigfoot TX IDE seen as 8.4 GB Message-ID: <199803280225.NAA13946@godzilla.zeta.org.au>
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>With LBA off, BIOS defaults to CHS, and as previously mentioned shows 23361 >cyl/16 hd/63 sec on the BIOS display (still 12 GIG), but feeBSD seems to >max out at 16383 cyl/16 hd/63 sec (still adds up to 8.4 GIG)... FreeBSD always uses CHS with whatever limits the drive reports (max 65535 cyl/16 hd/255 sec) (128G). Drives don't report more than 63 sectors due to BIOS braindamage. Apparently some drives don't report more than 16383 cylinders. I don't know of any BIOS bugs for >= 16384 cylinders. CHS BIOSes break at only 1024 cylinders. FreeBSD used to have a sign extension bug for >= 32768 cylinders. >Interestingly, I found this item (from Aug 96) that suggests there may be >an 8 GIG limit... > > "With BIOS LBA, the hard disk size limitation is virtually removed (well, > pushed up to 8 Gigabytes anyway). If you have an LBA BIOS, you can put > FreeBSD or any OS anywhere you want and not hit the 1024 cylinder limit." A BIOS limit. FreeBSD doesn't use the BIOS except for booting, but may be affected by drives dumbing down things so that BIOSes sort of work. Bruce To Unsubscribe: send mail to majordomo@FreeBSD.org with "unsubscribe freebsd-hardware" in the body of the message
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