From owner-cvs-all Tue Jul 28 19:27:11 1998 Return-Path: Received: (from daemon@localhost) by hub.freebsd.org (8.8.8/8.8.8) id TAA15521 for cvs-all-outgoing; Tue, 28 Jul 1998 19:27:11 -0700 (PDT) (envelope-from owner-cvs-all) Received: from rover.village.org (rover.village.org [204.144.255.49]) by hub.freebsd.org (8.8.8/8.8.8) with SMTP id TAA15515 for ; Tue, 28 Jul 1998 19:27:04 -0700 (PDT) (envelope-from imp@village.org) Received: from harmony [10.0.0.6] by rover.village.org with esmtp (Exim 1.71 #1) id 0z1Lwm-0002ai-00; Tue, 28 Jul 1998 20:26:32 -0600 Received: from harmony.village.org (localhost.village.org [127.0.0.1]) by harmony.village.org (8.8.8/8.8.3) with ESMTP id UAA27961; Tue, 28 Jul 1998 20:30:23 -0600 (MDT) Message-Id: <199807290230.UAA27961@harmony.village.org> To: asami@cs.berkeley.edu (Satoshi Asami) Subject: Re: very quick reboot Cc: committers@freebsd.org In-reply-to: Your message of "Tue, 28 Jul 1998 18:46:04 PDT." <199807290146.SAA00693@silvia.HIP.Berkeley.EDU> References: <199807290146.SAA00693@silvia.HIP.Berkeley.EDU> Date: Tue, 28 Jul 1998 20:30:23 -0600 From: Warner Losh Sender: owner-cvs-all@freebsd.org X-Loop: FreeBSD.org Precedence: bulk In message <199807290146.SAA00693@silvia.HIP.Berkeley.EDU> Satoshi Asami writes: : I'm wondering if it is possible to reboot a computer without actually : resetting the hardware. Assuming I want to reboot with the same : kernel (rebooting with different kernels obviously present more : challenges), can't I just re-load the initialized data and jump to the : address where the kernel starts executing? Unless the hardware is in a weird state, that should almost work. You'd also have to bzero the bss section of the kernel as well as recreate the boot information that was passed to the kernel from the boot blocks. The only thing that I'd worry about would be hardware that is set to a known state by the bios that FreeBSD then sets to a different known state which would be FUBAR'd if FreeBSD were to set that state again. Video might also be a problem, but since we can now make 16-bit BIOS calls, it should be less of a problem. There are likely other things that I've forgotten... I'm curious... why do you want to do this? Warner