Date: Sun, 14 Apr 1996 21:50:21 +0200 (MET DST) From: J Wunsch <j@uriah.heep.sax.de> To: freebsd-hackers@freebsd.org (FreeBSD hackers) Cc: dahanaya@chaph.usc.edu (Diyamanthi Dahanayake), efrain@bridge.net Subject: Re: Hard Drive (fwd) Message-ID: <199604141950.VAA08148@uriah.heep.sax.de> In-Reply-To: <199604141700.KAA04142@lvl-sun703.usc.edu> from "Diyamanthi Dahanayake" at Apr 14, 96 10:00:55 am
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As Diyamanthi Dahanayake wrote: > > ... and was > > wondering how BSD would behave with an 850MB or 1.2GB hard drive with > > LBA mode enabled in the MB Bios.... I dont have a lot of money so > > purchasing a SCSI controller and HD would be very difficult... Well, SCSI ain't that much more expensive than IDE, when you avoid the crap that occasionally pops up on the IDE front. Anyway, FreeBSD doesn't require the LBA mode, it actually doesn't use the BIOS except for booting. The ST-506 (WD1003/WD1007) register interface, as it's still been used by IDE drives in non-LBA mode, allows for up to 65536 cylinders (0 ... 65535) 16 heads (0 ... 15) 255 sectors (1 ... 255) This is 127.5 GB. Even considering the BIOS interface (interrupt 0x13) deficiencies, so you cannot use more than 63 sectors per track (1 ... 63) for any disk that needs to be accessed from the BIOS, it would still allow for 31.5 GB per drive. This is more than any currently available IDE drive. Note that all these values are ficticous, i.e. nothing of them does (or needs to) match any part of the actual physical geometry, which is opaque to the user. -- cheers, J"org joerg_wunsch@uriah.heep.sax.de -- http://www.sax.de/~joerg/ -- NIC: JW11-RIPE Never trust an operating system you don't have sources for. ;-)
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