Path: utzoo!utgpu!news-server.csri.toronto.edu!cs.utexas.edu!sdd.hp.com!apollo!vinoski From: vinoski@apollo.HP.COM (Stephen Vinoski) Newsgroups: comp.sys.apollo Subject: Re: Problems booting diskless on Ethernet Message-ID: <5011bdff.20b6d@apollo.HP.COM> Date: 27 Feb 91 19:03:00 GMT References: <50081142.1bc5b@pisa.ifs.umich.edu> Sender: root@apollo.HP.COM Reply-To: vinoski@apollo.HP.COM (Stephen Vinoski) Organization: Hewlett-Packard Apollo Division - Chelmsford, MA Lines: 42 In article <50081142.1bc5b@pisa.ifs.umich.edu> rees@citi.umich.edu (Jim Rees) writes: >In article , hanche@imf.unit.no (Harald Hanche-Olsen) writes: > Does anybody know anything about the protocol used when booting > diskless from another node? >The net read routine in the PROM is very simple-minded. It does no timeout/ >retransmission. That means that if you have trouble loading netboot, you >have to start over. I don't remember whether netboot (the thing that says >".......loaded xxx bytes" does much better, but you used to be able to get >it to retry by hitting the space bar. Jim is right (of course :-), the PROM network routines are quite dumb. Harald mentioned that any non-boot packets sent to the diskless node seem to cause trouble; this is because at the PROM level, there are no such things as separate sockets - the PROM believes every packet is intended for it. A non-boot packet would contain the wrong format and could cause the trouble he is seeing. One thing that even Jim might not be aware of is that netboot was augmented back around the sr10 timeframe to keep track of the boot pages received and retry for the ones it didn't get. We found that a surprising number of pages were being dropped and had to add this checking. The retry mechanism is not real smart but it appears to work. The boot programs have to fit into very limited memory space so more robust checking is not possible. >You can also read the stdout from netman (by running it in a pad, for >example) and it may tell you about problems it's having communicating with >the partner. I would recommend this. Like I said above, netboot has to run on bare hardware in a very tight memory space, so it doesn't handle errors too gracefully. The netman program, however, has the full power of the OS underneath it, so it can be a little more verbose about what it's doing. -steve | Steve Vinoski (508)256-0176 x5904 | Internet: vinoski@apollo.hp.com | | HP Apollo Division, Chelmsford, MA 01824 | UUCP: ...!apollo!vinoski | | "The price of knowledge is learning how little of it you yourself harbor." | | - Tom Christiansen |