diff --git a/sys/man/8/9boot b/sys/man/8/9boot index 16062dd39..f1014c00d 100644 --- a/sys/man/8/9boot +++ b/sys/man/8/9boot @@ -1,76 +1,78 @@ .TH 9BOOT 8 .SH NAME -9bootfat, 9bootiso, 9bootpxe \- bootloaders for pc FAT, ISO and PXE network booting +9bootfat, 9bootiso, 9bootpxe \- PC bootloader for FAT, ISO and PXE network booting .SH SYNOPSIS -started by BIOS or chainloaded by partition bootsector +started by PC BIOS or chainloaded by partition bootsector .SH DESCRIPTION -The bootloader is responsible for reading the +9boot is the bootloader used on PCs to start the Plan 9 kernel. +Its task is to read and parse the .IR plan9.ini (8) -boot parameters and booting a kernel. It interprets the +configuration file, gather some basic system information like +the amount of usable system memory, do some low level system +initialization and load the kernel from the boot media into memory. + +After reading the configuration, the loader will automatically +attempt to boot the kernel that was specified by the .B bootfile= -parameter as a file path on the current boot media -to locate the kernel image. The path should be in all -lower case except for -.IR 9bootpxe -wich supports case sensitive file names. Read parameters -are echoed on the console. The boot procedure -can be interrupted by pressing any key after the configuration -was read. The interactive boot console is indicated with a -.B > -prompt. The syntax of the boot console is the same as in +parameter. If there is no such parameter, a key +gets pressed on the keyboard or the kernel file was not +found then the loader enters the interactive +boot console. + +The syntax of the boot console is the same as in the .IR plan9.ini (8) -file. The word -.B clear -will reset all current parameters. The word +file. +.BR +The word +.B clear [ +.I prefix +] +can be used to remove parameters from the current configuration. +If a +.IR prefix +is specified, the first parameter that matches the prefix +is removed. If the +.IR prefix +argument is omited, the whole configuration will be reset. +.BR +The word .B boot -will end the console and resume booting the kernel. The boot -console is entered automatically when: boot failed, no -.B bootfile= -parameter was specified or no -.IR plan9.ini (8) -was found. +will end the console and resume booting the kernel. + +There are many ways to boot a PC so +.IR 9boot +was split into a number of distinct programs one for each boot +method. .SH FAT BOOTING -The -.IR 9bootfat -program is responsible for loading the kernel from -the +When booting Plan 9 from a harddisk or USB pen drive, a +FAT16/32 partition ( .IR 9fat -partition into memory and passing it the +) is used to store the kernel and .IR plan9.ini (8) -boot parameters. It is chainloaded by -.IR pbs, -wich locates it in the root of the active -FAT partition. The -.IR plan9.ini (8) -file is read from the root directory of the FAT -filesystem. +configuration. Due to size limitations, instead of loading +the kernel directly, the bootsector ( +.IR pbs +) of the FAT partition loads +a 2nd stage bootloader +.IR 9bootfat +from the root directory of the filesystem. .SH CD-ROM BOOTING -Booting from CD-ROM requires +Booting from CD-ROM requires only .IR 9bootiso to be included in the ISO-9660 image under .B 386/9bootiso, set as a non emulation bootblock (see .IR mk9660 (8)). -The BIOS loads the first 2K of -.B 386/9bootiso -into memory and then executes the program. The remainder -of the file is then read to complete the chainloading process. Boot parameters are read from .B cfg/plan9.ini. .SH NETWORK BOOTING -With a PXE capable BIOS and network card it is possible for -a machine to download +With a PXE capable BIOS and network card one can download .IR 9bootpxe -and a kernel from a tftp server. The location of -.IR 9bootpxe -is defined by the -.B bootf=/386/9bootpxe -line in the tftp server's +and boot the kernel from a TFTP server (see +.IR dhcpd (8), .IR ndb (6) -entry. -.BR -Once started, +for details). Once started, .IR 9bootpxe will read the file .B /cfg/pxe/$ether @@ -82,3 +84,14 @@ in lower case hex, and use this as its file. .SH SOURCE .BR /sys/src/boot/pc . +.SH FILES +.TP +.B /386/pbs +.TP +.B /386/9bootfat +.TP +.B /386/9bootiso +.TP +.B /386/9bootpxe +.SH "SEE ALSO" +.IR plan9.ini (8)