Date: Fri, 21 Nov 1997 02:20:45 -0600 From: Tony Overfield <tony@dell.com> To: Terry Lambert <tlambert@primenet.com> Cc: hackers@freebsd.org Subject: Re: >64MB Message-ID: <3.0.3.32.19971121022045.00760330@bugs.us.dell.com> In-Reply-To: <199711191822.LAA14282@usr05.primenet.com> References: <3.0.3.32.19971118043753.0071582c@bugs.us.dell.com>
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Terry Lambert wrote: >> >2) The BIOS INT 13 code has a 2G limit on partition size, unless >> > you can guarantee all the devices in your machine support >> > LBA mode (even then the limit on LBA is lower than the limit >> > in FreeBSD... 64bits >> 32 bits). >> >> Second, the INT 13 interface (without LBA mode) is limited >> to 8.4 GB, not 2 GB. > >A DOS partition (assuming we use the DOS MBR and aren't idiots, we >are tied to the DOS partition table) is limited to C/H/S values. A C/H/S value is limited to 8.4 GB, not 2 GB. There is no INT 13 limit anywhere near 2 GB. Your claim that "The BIOS INT 13 code has a 2G limit on partition size" is wrong. I have created many partitions larger than 2 GB, as have many other people. >You have tha ability to map an 8G space with four descriptors. Yes, and you can also map an 8G space with two 4G "descriptors," or one 8G "descriptor," or even sixteen .5G "descriptors." DOS ordinarily creates a primary partition and an optional extended partition. The extended partition can contain an unlimited number of secondary partitions. No matter how many partitions you create in DOS, you'll only use two of the four top-level partition entries. >> Third, the limit for LBA INT 13 is 64-bits worth of sectors, or >> 2^73 bytes. This should last us for several more years. > >The LBA limit is irrelevant. You claimed that LBA was limited to 32 bits and that's wrong. Suddenly deeming it irrelevant doesn't change that. >It's not usable, so it might as well be fiction. No. LBA mode _is_ usable. I use it every day, without any problems. - Tony
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