Date: Thu, 09 May 2002 15:01:10 -0700 From: Terry Lambert <tlambert2@mindspring.com> To: Michael Smith <msmith@mass.dis.org> Cc: Gordon Tetlow <gordont@gnf.org>, hackers@freebsd.org Subject: Re: nextboot loader diff Message-ID: <3CDAF1A6.13DB883D@mindspring.com> References: <200205091911.g49JBaI3002178@mass.dis.org>
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Michael Smith wrote: > I still think you're not thinking the processes associated with this > feature through carefully enough. Liten to Mike; he is the loader guru. I don't know how the file I/O is done for the "YES/NO" change, since I have to have a couple of browsers open to read FORTH code. 8-(. However, the prototype I worked on at ClickArray with James (both guys who eventually donated code in that area were ClickArray folks) assumed that it would rewrite the file with equal length contents, as being the only safe way to do a write from the FORTH code. The way it was planned to work out was to have a file that had a line listing root devices, and then rotor through the list, rewriting it, as part of the boot process, e.g.: "device1 device1 device1 device2 device2 device2" -> "device1 device1 device2 device2 device2 device1" ... The existance or non-existance of the file was the "yes" or "no". This is slightly different than the code that Archie, Julian, and Doug worked out before I started at Whistle (the original "nextboot" code), but it has the same properties. Unfortunately, it wasn't really possible (no room, no write code in the boot2, no room for write code in the boot2!) to keep the list in the boot sector. Rewriting a file in any case, almost makes it so that the boot code, containing the file, is on its own partition. Otherwise, you get screwed when one partition fails and the other does not (it's a cris-cross) and you go to update. 8-(. So I definitely agree with Mike here. Maybe you could ask Archie or Ambrisko to clarify the feature you're trying to replace, and then ask Mike about the code needed to do that? -- Terry To Unsubscribe: send mail to majordomo@FreeBSD.org with "unsubscribe freebsd-hackers" in the body of the message
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