Relay-Version: version B 2.10 5/3/83; site utzoo.UUCP Posting-Version: version B 2.10.2 9/18/84; site brl-tgr.ARPA Path: utzoo!linus!philabs!cmcl2!seismo!brl-tgr!gwyn From: gwyn@brl-tgr.ARPA (Doug Gwyn) Newsgroups: net.unix Subject: Re: How to save core images ??? Message-ID: <596@brl-tgr.ARPA> Date: Sat, 10-Aug-85 05:11:47 EDT Article-I.D.: brl-tgr.596 Posted: Sat Aug 10 05:11:47 1985 Date-Received: Mon, 12-Aug-85 07:40:50 EDT References: <39300040@uiucdcs> <443@othervax.UUCP> Organization: Ballistic Research Lab Lines: 19 > Very interesting that this hasn't come up before (or has it?). It has > always amazed me that this is not a standard feature of all operating > systems, and I have had to implement various kludges over the years to > enable checkpoint/restart capabilities. Yes, it has come up several times. Nobody has answered the most fundamental objection, which is that the state of a process really includes the state of pipes to other processes, the state of the terminal, the state of files, etc. so that virtually the entire system would have to be checkpointed to provide a working general facility. There have been numerous attempts to checkpoint UNIX processes from user mode, but to do it right you would need the help of the kernel (since the code being checkpointed is still undergoing modification during the checkpoint process, otherwise). Apart from saving a bit of work in initializing large amounts of data, why do you feel this feature is necessary?