Date: Thu, 23 Nov 2000 19:53:26 -0500 From: Michael Graziano <mikeg@hoflink.com> To: stable@FreeBSD.org Subject: Re: Dedicated disks (was: Dangerously Dedicated) Message-ID: <3A1DBC06.E2DA8053@hoflink.com> References: <200011231744.JAA02382@spammie.svbug.com>
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Regarding some of the points raised at http://www.svbug.com/projects/platform_issues/ddvsbios/index.html, >You can not easily add another OS to an existing system, >without a full backup and restore and >Commerical boot managers have problems with it; this is >an issue when you have FreeBSD on one "Dangerously >Dedicated" disk, and anohter OS on a second disk Since this is a dedicated install, you shouldn't be trying to add other operating systems to the machine. That defeats the whole purpose of creating a dedicated FreeBSD system. The way I aways interpreted "Dangerously Dedicated" disks is that the only OS on the MACHINE should be FreeBSD - Nothing else should ever run on that box. That is how I have always treated the Dangerously Dedicated option. (before I get flamed yes I DO understand that you can have a DD Disk in a machine as the second, third or whatever drive and not boot off of it, but I feel that DD disks are really only for people who will be using FreeBSD as their ONLY OS on a given machine) >An increasing number of BIOS will divide by 0 when they >are attempting to implement LBA addressing. These I remember reading somewhere that you should turn off LBA mode when installing FreeBSD anyway (that information may be dated now, and for all I know may not have been accurate when I read it (back in the 2.2.x days)). I have always set my FreeBSD systems to use normal mode for accessing the hard drive, and have always used DD disks without a problem. Machines from Compaq, SAG Electronics, IBM desktops and Laptops as well as a variety of systems I built myself (my home-built systems all use Award or AMI BIOSen, that leaves Phoenix untested and I would like to hear from someone who has experience with them) all have no problems with DD disks. This covers a significant part of the PC BIOS market share. >The FreeBSD fake DOS partition table does not pass a >number BIOS-based self-consistency checks (it needs to >be fixed), and so systems which use these checks in the >BIOS to protect against boot sector virus infestation _can >not boot_. By all means PLEASE fix it or suggest how it can be fixed. I would be all for making it work, but I've also been burned with other operating systems and "Boot Sector Virus Protection" in BIOS (it whines about DOS installs, Linux (RedHat), NetBSD, OpenBSD, and even Win95 and 98. I have found it to be more of a hinderance than a help and have turned it off on every system I use. On a FreeBSD system I think it would be BETTER to leave it turned off. IMHO it is a stupid feature which is useful for Win/DOS users who love to boot from floppies that their friends gave them or run strange programs off the 'net, but on a UNIX box I doubt people will be booting from untrusted floppies and unless you run something funky as root you can't do much damage to the system from inside the OS. At most I would think this warrants a FAQ or Handbook entry advising people to turn off the feature (if one isn't already there). Even if there aren't many real benefits to DD Disks, I think their creation should still be allowed and supported. Perhaps a more explicit warning in sysinstall (something to the effect of "If you are using a laptop and do a suspend to disk this will hose your system" coupled with "This violates the PC-standards and may cause serious problems") is in order. The current warning is somewhat wussy (to say the least). Honestly though, I see no harm in leaving this option in and I am seriously in favor of it remaining. It follows the same logic as the IDE_DELAY option for a kernel, if people are playing with it they should know what they are doing, and if not the warning should be enough to keep them from losing a finger to the firecrackers. /~mikeg Questions, comments, problems, flames, praise, small bundles of money to mikeg@hoflink.com SPAM, dead cows, fish-in-newspaper, death threats, etc. to billgates@microsoft.com To Unsubscribe: send mail to majordomo@FreeBSD.org with "unsubscribe freebsd-stable" in the body of the message
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