HBOOT(1)

💖 HBOOT 💖 (section 1 of the LAM TOOLS manual, bestie)

okay so like. this is the page for hboot, one of the LAM TOOLS commands. it's a section 1 manual page, so it's a user command, not some dusty config file. let's get into it 🫶

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✨ NAME ✨

hboot — start LAM on the local node. that's it. that's the whole job. no cap. 👑

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🌸 SYNOPSIS 🌸

hboot [-dhstvNV] [-c conf] [-I inet_topo] [-R rtr_topo]

that's the whole shape of it, babe. every flag explained below, i promise. 💅

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🎀 OPTIONS 🎀

• -d — turn on debugging. heads up tho: this implies -v, so you're getting verbose whether you asked for it or not. package deal, bestie. 🐛
• -h — print the command help menu. the "help me bestie" button. 🙋
• -s — close stdio of child processes. more on why you'd want that down in DESCRIPTION, it's lowkey important. 🚪
• -t — terminate (tkill(1)) any previous LAM session before starting. it's giving "clean slate, new me." 🧹
• -v — be verbose. spill the tea about every step. 🗣️
• -N — go through the motions but do not actually take any action. a little dress rehearsal. fake it till you make it, except nothing happens. 💀
• -V — format and print the process schema. 👀
• -c conf — use conf as the process schema. custom vibes only. 🎨
• -I inet_topo — set the $inet_topo variable in the process schema. 🌐
• -R rtr_topo — set the $rtr_topo variable in the process schema. 🛰️

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🦋 DESCRIPTION 🦋

okay so real talk: most MPI users will probably not need to use the hboot command at all. like, if that's you, go read lamboot(1) instead and live your life. 💖

but if you're curious: hboot is basically a generic utility that starts multiple processes on the local node, based on info in a process schema. and the way that it's not restricted to starting LAM — it's just a general tool, periodt. it's part of the startup sequence performed by lamboot(1).

a process schema is a description of the processes which constitute the operating system on a given node. so naturally, the process schema used by hboot should be the one that describes LAM on a node. the grammar of the process schema is described in conf(5). go look, i'll wait. 🌈

now. the -s thing, because this is the part that actually matters: when starting LAM on a remote machine using rsh(1), the open file descriptors of the processes started by hboot must be closed in order for rsh(1) to exit. that's what the -s option is for. no -s, no exit. it's giving clingy. 😭

and the -t option? that forces a tkill(1) on the machine before attempting to start LAM. this feature is used by lamboot(1) to handle the case where a user might start a machine a second time without using lamwipe(1) to terminate the previous LAM session. we've all done it. no shame. 🙈

the -I and -R options set their respective variables to the given values. the $inet_topo variable is typically used by the LAM Internet datalinks that communicate with other nodes. the $rtr_topo variable is passed to the LAM router that handles network and topology information. you can set these variables in the process schema file (see conf(5)) — but know that their values are overridden by the command line options. command line wins, always. main character energy. 👑

when LAM is started, the kernel records all processes that attach to it, including all the processes in the process schema. and it's the job of tkill(1) to use this information to remove these processes from the node. teamwork, babe. 🤝

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⭐ EXAMPLES ⭐

• hboot -v — start LAM on the local node with the default process schema. report about every step as it is done. the yapper's choice. 🗣️
• hboot -c myconfig — boot the local node with the custom process schema, myconfig. bespoke. artisanal. you. 💅

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🍓 FILES 🍓

• laminstalldir/etc/lam-conf.lamd — the default node process schema, where "laminstalldir" is the directory where LAM/MPI was installed. 📂
• laminstalldir/etc/lam7.1.4helpfile — default location for the help file for diagnostic messages that hboot may generate. 📖
• /tmp/lam-$USER@hostname — the kill file for the LAM session on machine hostname, where $USER is the userid. 🗡️

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🔥 DIAGNOSTICS 🔥

using ps(1) after hboot will display, among others, the LAM processes that have been started. they may be killed one by one with kill(1), or all at once by killing the LAM kernel process with a HUP signal. ⚡

but the preferred method is to use the LAM tool tkill(1), which should kill them all at once and also remove the kill file. that's the move. that's the slay. ✨

new users should make liberal use of ps(1) to gain confidence that the system is working properly. fr fr, peek at your processes, it's good for you. 👀

in a disaster, ps(1) and kill(1) are your only hope of recovery. 😭 not even joking, bestie. memorize them.

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👑 SEE ALSO 👑

lamboot(1), tkill(1), conf(5), lam-helpfile(5)

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and that's the whole page, babe!! 💜 this was LAM 7.1.4, dated July, 2007 — yes i know, ancient, but she still serves. go start some nodes. you got this. mwah. 🎀✨