From owner-freebsd-hackers Sun Mar 12 16: 6:46 2000 Delivered-To: freebsd-hackers@freebsd.org Received: from mycenae.ilion.eu.org (mycenae.ilion.eu.org [203.35.206.129]) by hub.freebsd.org (Postfix) with ESMTP id E985537B50E for ; Sun, 12 Mar 2000 16:06:37 -0800 (PST) (envelope-from patrykz@ilion.eu.org) Received: from mycenae.ilion.eu.org (localhost [127.0.0.1]) by mycenae.ilion.eu.org (8.9.3/8.9.3) with ESMTP id LAA05238; Mon, 13 Mar 2000 11:06:26 +1100 (EST) (envelope-from patrykz@mycenae.ilion.eu.org) Message-Id: <200003130006.LAA05238@mycenae.ilion.eu.org> To: Gary Jennejohn Cc: freebsd-hackers@FreeBSD.ORG Subject: Re: 5.0 features? In-reply-to: Your message of "Mon, 13 Mar 2000 00:37:10 BST." <200003122337.AAA25674@peedub.muc.de> Date: Mon, 13 Mar 2000 11:06:26 +1100 From: Patryk Zadarnowski Sender: owner-freebsd-hackers@FreeBSD.ORG Precedence: bulk X-Loop: FreeBSD.ORG > Mark Hittinger writes: > > > >Something that the old DEC took a few stabs at was the idea of a > >"checkpoint" feature where a process or a series of processes could be > >put in a quiesced state. This would page out the process or processes > >into the swap space, allow a hardware shutdown, and after a reboot allow > >the restart of the checkpointed process(es). > > > > I did something like this for Philips while I was at UniSoft. It > depended on some special hardware features (turning off/losing power > generated an interrupt, there was a small UPS in the box along with > battery-backed SRAM to save various kernel structures). > > Turning off the power caused all memory to be saved to disk (the kernel > turned off the UPS after it was done). Upon a restart the kernel noticed > that memory had been saved, read the contents in from disk, futzed around > with some structures, and restarted what was curproc at the time of > shutdown. It even worked ;-) > > Philips never did anything with it. Out of pure curiosity, what did you do with pending interrupts, partially completed DMA transfers and other such state information? Pat. -=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=- Patryk Zadarnowski University of New South Wales -=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=- To Unsubscribe: send mail to majordomo@FreeBSD.org with "unsubscribe freebsd-hackers" in the body of the message