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Mercurial > hg > plan9front / sys/man/8/plan9.ini

changeset 7215: e4dad4f80c6c
parent: dbfa116110e2
child: 874554781a81
author: cinap_lenrek@felloff.net
date: Tue, 07 May 2019 11:41:33 +0200
permissions: -rw-r--r--
description: plan9.ini(8), boot(8): clarify the use of $rootdir and $rootspec
1 .TH PLAN9.INI 8
2 .SH NAME
3 plan9.ini \- configuration file for PCs
4 .SH SYNOPSIS
5 .I none
6 .SH DESCRIPTION
7 When booting Plan 9 on a PC, the bootloader program
8 .IR 9boot (8)
9 first reads configuration information from a file
10 on the boot media.
11 This file,
12 .BR plan9.ini ,
13 looks like a shell script containing lines of the form
14 .IP
15 .EX
16 name=\f2value\fP
17 .EE
18 .LP
19 each of which defines a kernel or device parameter.
20 .PP
21 Blank lines and
22 Carriage Returns
23 .IB ( \er )
24 are ignored.
25 .B #
26 comments are ignored, but are only recognised if
27 .L #
28 appears at the start of a line.
29 .PP
30 For devices, the generic format of
31 .I value
32 is
33 .IP
34 .EX
35 type=TYPE [port=N] [irq=N] [mem=N] [size=N] [dma=N] [ea=N]
36 .EE
37 .LP
38 specifying the controller type,
39 the base I/O port of the interface, its interrupt
40 level, the physical starting address of any mapped memory,
41 the length in bytes of that memory, the DMA channel,
42 and for Ethernets an override of the physical network address.
43 Not all elements are relevant to all devices; the relevant values
44 and their defaults are defined below in the description of each device.
45 .PP
46 The file is used by the kernel to configure the hardware available.
47 The information it contains is also passed to the boot
48 process, and subsequently other programs,
49 as environment variables
50 (see
51 .IR boot (8)).
52 However, values whose names begin with an asterisk
53 .B *
54 are used by the kernel and are not converted into environment variables.
55 .PP
56 The following sections describe how variables are used.
57 .SS ETHERNET
58 .SS \fLether\fIX\fL=\fIvalue\fP
59 This defines an Ethernet interface.
60 .IR X ,
61 a unique monotonically increasing number beginning at 0,
62 identifies an Ethernet card to be probed at system boot.
63 Probing stops when a card is found or there is no line for
64 .BR etherX+1 .
65 After probing as directed by the
66 .BI ether X
67 lines, any remaining Ethernet cards that can be automatically
68 detected are added.
69 Almost all cards can be automatically detected.
70 For debugging purposes, automatic probing can
71 be disabled by specifying the line
72 .BR *noetherprobe= .
73 .PP
74 Some cards are software configurable and do not require all options.
75 Unspecified options default to the factory defaults.
76 .PP
77 Known
78 .IR TYPE s
79 are
80 .\" .TF ga620
81 .TF vt6102
82 .PD
83 .TP
84 .B igbe
85 The Intel 8254X Gigabit Ethernet controllers,
86 as found on the Intel PRO/1000 adapters for copper (not fiber).
87 Completely configurable.
88 .TP
89 .B igbepcie
90 The Intel 8256[36], 8257[12], and 82573[ev] Gigabit Ethernet
91 PCI-Express controllers.
92 Completely configurable.
93 .TP
94 .B rtl8169
95 The Realtek 8169 Gigabit Ethernet controller.
96 Completely configurable.
97 .TP
98 .B ga620
99 Netgear GA620 and GA620T Gigabit Ethernet cards,
100 and other cards using the Alteon Acenic chip such as the
101 Alteon Acenic fiber and copper cards,
102 the DEC DEGPA-SA and the SGI Acenic.
103 Completely configurable.
104 .TP
105 .B dp83820
106 National Semiconductor DP83820-based Gigabit Ethernet adapters, notably
107 the D-Link DGE-500T.
108 Completely configurable.
109 .TP
110 .B vgbe
111 The VIA Velocity Gigabit Ethernet controller.
112 Known to drive the VIA8237 (ABIT AV8), but at 100Mb/s full-duplex only.
113 .TP
114 .B m10g
115 The Myricom 10-Gigabit Ethernet 10G-PCIE-8A controller.
116 Completely configurable.
117 Can't boot through these due to enormous firmware loads.
118 .TP
119 .B i82598
120 The Intel 8259[89] 10-Gigabit Ethernet PCI-Express controllers.
121 Completely configurable.
122 .TP
123 .B i82557
124 Cards using the Intel 8255[789] Fast Ethernet PCI Bus LAN Controller such as the
125 Intel EtherExpress PRO/100B.
126 Completely configurable, no options need be given.
127 If you need to force the media, specify
128 one of the options (no value)
129 .BR 10BASE-T ,
130 .BR 10BASE-2 ,
131 .BR 10BASE-5 ,
132 .BR 100BASE-TX ,
133 .BR 10BASE-TFD ,
134 .BR 100BASE-TXFD ,
135 .BR 100BASE-T4 ,
136 .BR 100BASE-FX ,
137 or
138 .BR 100BASE-FXFD .
139 Completely configurable.
140 .TP
141 .B 2114x
142 Cards using the Digital Equipment (now Intel) 2114x PCI Fast Ethernet Adapter Controller,
143 for example the Netgear FA310.
144 Completely configurable, no options need be given.
145 Media can be specified the same was as for the
146 .BR i82557 .
147 Some cards using the
148 .B PNIC
149 and
150 .B PNIC2
151 near-clone chips may also work.
152 .TP
153 .B 83815
154 National Semiconductor DP83815-based adapters, notably
155 the Netgear FA311, Netgear FA312, and various SiS built-in
156 controllers such as the SiS900.
157 On the SiS controllers, the Ethernet address is not detected properly;
158 specify it with an
159 .B ea=
160 attribute.
161 Completely configurable.
162 .TP
163 .B rtl8139
164 The Realtek 8139 Fast Ethernet controller.
165 Completely configurable.
166 .TP
167 .B vt6102
168 The VIA VT6102 Fast Ethernet Controller (Rhine II).
169 .TP
170 .B smc91cxx
171 SMC 91cXX chip-based PCMCIA adapters, notably the SMC EtherEZ card.
172 .TP
173 .B elnk3
174 The 3COM Etherlink III series of cards including the 5x9, 59x, and 905 and 905B.
175 Completely configurable, no options need be given.
176 The media may be specified by setting
177 .B media=
178 to the value
179 .BR 10BaseT ,
180 .BR 10Base2 ,
181 .BR 100BaseTX ,
182 .BR 100BaseFX ,
183 .BR aui ,
184 and
185 .BR mii .
186 If you need to force full duplex, because for example the Ethernet switch does not negotiate correctly,
187 just name the word (no value)
188 .B fullduplex
189 or
190 .BR 100BASE-TXFD .
191 Similarly, to force 100Mbit operation, specify
192 .BR force100 .
193 Port 0x110 is used for the little ISA configuration dance.
194 .TP
195 .B 3c589
196 The 3COM 3C589 series PCMCIA cards, including the
197 3C562 and the 589E.
198 There is no support for the modem on the 3C562.
199 Completely configurable, no options need be given.
200 Defaults are
201 .EX
202  port=0x240 irq=10
203 .EE
204 The media may be specified as
205 .B media=10BaseT
206 or
207 .BR media=10Base2 .
208 .TP
209 .B ec2t
210 The Linksys Combo PCMCIA EthernetCard (EC2T),
211 EtherFast 10/100 PCMCIA cards (PCMPC100) and integrated controllers (PCM100),
212 the Netgear FA410TX 10/100 PCMCIA card
213 and the Accton EtherPair-PCMCIA (EN2216).
214 Completely configurable, no options need be given.
215 Defaults are
216 .EX
217  port=0x300 irq=9
218 .EE
219 These cards are NE2000 clones.
220 Other NE2000 compatible PCMCIA cards may be tried
221 with the option
222 .EX
223  id=string
224 .EE
225 where
226 .B string
227 is a unique identifier string contained in the attribute
228 memory of the card (see
229 .IR pcmcia (8));
230 unlike most options in
231 .BR plan9.ini ,
232 this string is case-sensitive.
233 The option
234 .B dummyrr=[01]
235 can be used to turn off (0) or on (1) a dummy remote read in the driver
236 in such cases,
237 depending on how NE2000 compatible they are.
238 .TP
239 .B ne2000
240 Not software configurable iff ISA;
241 PCI clones or supersets are software configurable;
242 includes the Realtek 8029 clone used by Parallels.
243 16-bit card.
244 Defaults are
245 .EX
246  port=0x300 irq=2 mem=0x04000 size=0x4000
247 .EE
248 The option (no value)
249 .B nodummyrr
250 is needed on some (near) clones to turn off a dummy remote read in the driver.
251 .TP
252 .B amd79c970
253 The AMD PCnet PCI Ethernet Adapter (AM79C970).
254 (This is the Ethernet adapter used by VMware.)
255 Completely configurable, no options need be given.
256 .TP
257 .B wd8003
258 Includes WD8013 and SMC Elite and Elite Ultra cards. There are varying degrees
259 of software configurability. Cards may be in either 8-bit or 16-bit slots.
260 Defaults are
261 .EX
262  port=0x280 irq=3 mem=0xD0000 size=0x2000
263 .EE
264 BUG: On many machines only the 16 bit card works.
265 .TP
266 .B bcm
267 Broadcom BCM57xx Gigabit Ethernet controllers.
268 Completely configurable, no options need be given.
269 .TP
270 .B yuk
271 Marvell 88e8057 Yukon2 Gigabit Ethernet controller.
272 Completely configurable, no options need be given.
273 .TP
274 .B virtio
275 Virtual Ethernet interface provided by QEMU/KVM and VirtualBox.
276 No options need be given. The MAC address can be changed with the
277 .B ea=
278 option.
279 .TP
280 .B sink
281 A
282 .B /dev/null
283 for Ethernet packets \(em the interface discards sent
284 packets and never receives any.
285 This is used to provide a test bed for
286 some experimental Ethernet bridging software.
287 .TP
288 .B wavelan
289 Lucent Wavelan (Orinoco) IEEE 802.11b
290 and compatible PCMCIA cards.
291 Compatible cards include the Dell TrueMobile 1150
292 and the Linksys Instant Wireless Network PC Card.
293 Port and IRQ defaults are 0x180 and 3 respectively.
294 .IP
295 These cards take a number of unique options to aid in
296 identifying the card correctly on the 802.11b network.
297 The network may be
298 .I "ad hoc"
299 or
300 .I managed
301 (i.e. use an access point):
302 .EX
303  mode=[adhoc, managed]
304 .EE
305 and defaults to
306 .IR managed .
307 The 802.11b network to attach to
308 .RI ( managed
309 mode)
310 or identify as
311 .RI ( "ad hoc"
312 mode),
313 is specified by
314 .EX
315  essid=string
316 .EE
317 and defaults to a null string.
318 The card station name is given by
319 .EX
320  station=string
321 .EE
322 and defaults to
323 .IR "Plan 9 STA" .
324 The channel to use is given by
325 .EX
326  channel=number
327 .EE
328 where
329 .I number
330 lies in the range 1 to 16 inclusive;
331 the channel is normally negotiated automatically.
332 .IP
333 If the card is capable of encryption,
334 the following options may be used:
335 .EX
336  crypt=[off, on]
337 .EE
338 and defaults to
339 .IR on .
340 .EX
341  key\fIN\fP=string
342 .EE
343 sets the encryption key
344 .I N
345 (where
346 .I N
347 is in the range 1 to 4 inclusive) to
348 .IR string ;
349 this will also set the transmit key to
350 .I N
351 (see below).
352 There are two formats for
353 .I string
354 which depend on the length of the string.
355 If it is exactly 5 or 13 characters long it is assumed
356 to be an alphanumeric key; if it is exactly 10 or 26 characters
357 long the key is assumed to be in hex format (without a leading
358 .IR 0x ).
359 The lengths are checked,
360 as is the format of a hex key.
361 .EX
362  txkey=number
363 .EE
364 sets the transmit key to use to be
365 .I number
366 in the range 1 to 4 inclusive.
367 If it is desired to exclude or include unencrypted packets
368 .EX
369  clear=[off, on]
370 .EE
371 configures reception and defaults to inclusion.
372 .IP
373 The defaults are intended to match the common case of
374 a managed network with encryption and a typical entry would
375 only require, for example
376 .EX
377  essid=left-armpit key1=afish key2=calledraawaru
378 .EE
379 if the port and IRQ defaults are used.
380 These options may be set after boot by writing to the device's
381 .I ctl
382 file using a space as the separator between option and value, e.g.
383 .EX
384  echo 'key2 1d8f65c9a52d83c8e4b43f94af' >/net/ether0/0/ctl
385 .EE
386 .IP
387 Card-specific power management may be enabled/disabled by
388 .EX
389  pm=[on, off]
390 .EE
391 .TP
392 .B wavelanpci
393 PCI Ethernet adapters that use the same Wavelan
394 programming interface.
395 Currently the only tested cards are those based on the
396 Intersil Prism 2.5 chipset.
397 .
398 .TP
399 .B iwl
400 Intel Wireless WiFi Link mini PCI-Express adapters require
401 firmware from
402 .B http://firmware.openbsd.org/firmware/*/iwn-firmware*.tgz
403 to be present on attach in
404 .B /lib/firmware
405 or
406 .B /boot.
407 To limit the selected APs the options
408 .B essid=
409 and
410 .B bssid=
411 may be set at boot or in the ether interface clone file
412 using a space as the separator between option and value, e.g.
413 .EX
414  echo essid left-armpit >/net/ether1/clone
415 .EE
416 Scan results appear in the
417 .B ifstats
418 file and can be read out like:
419 .EX
420  cat /net/ether1/ifstats
421 .EE
422 Ad-hoc mode or WEP encryption is currently not supported.
423 To enable WPA/WPA2 encryption, see
424 .IR wpa (8)
425 for details.
426 .TP
427 .B rt2860
428 Ralink Technology PCI/PCI-Express wireless adapters require
429 firmware from
430 .B http://firmware.openbsd.org/firmware/*/ral-firmware*.tgz
431 to be present on attach in
432 .B /lib/firmware
433 or
434 .B /boot.
435 See iwl section above for configuration details.
436 .TP
437 .B wpi
438 Intel PRO Wireless 3945abg PCI/PCI-Express wireless adapters require
439 firmware from
440 .B http://firmware.openbsd.org/firmware/*/wpi-firmware*.tgz
441 to be present on attach in
442 .B /lib/firmware
443 or
444 .B /boot.
445 See iwl section above for configuration details.
446 .SS \fLnora6=
447 Disable automatic IPv6 configuration from incoming router advertisements.
448 .SS DISKS, TAPES
449 (S)ATA controllers are autodetected.
450 .SS \fL*nodma=\fP
451 disables dma on ata devices.
452 .SS \fL*sd\fIXX\fLdma=on\fP
453 explicitly enables dma on a specific ata device.
454 .SS \fLscsi\fIX\fL=value\fP
455 This defines a SCSI interface which cannot be automatically detected
456 by the kernel.
457 .PP
458 Known
459 .IR TYPE s
460 are
461 .TP
462 .B aha1542
463 Adaptec 154x series of controllers (and clones).
464 Almost completely configurable, only the
465 .EX
466  port=0x300
467 .EE
468 option need be given.
469 .PP
470 NCR/Symbios/LSI-Logic 53c8xx-based adapters
471 and Mylex MultiMaster (Buslogic BT-*) adapters are
472 automatically detected and need no entries.
473 .PP
474 By default, the NCR 53c8xx driver searches for up to 32 controllers.
475 This can be changed by setting the variable
476 .BR *maxsd53c8xx .
477 .PP
478 By default the Mylex driver resets SCSI cards by using
479 both the hard reset and SCSI bus reset flags in the driver interface.
480 If a variable
481 .BR *noscsireset
482 is defined, the SCSI bus reset flag is omitted.
483 .SS \fLaoeif=\fP\fIlist\fP
484 This specifies a space-separated
485 .I list
486 of Ethernet interfaces to be bound at boot to the ATA-over-Ethernet driver,
487 .IR aoe (3).
488 For example,
489 .LR "aoeif=ether0 ether1" .
490 Only interfaces on this list will initially be accessible via AoE.
491 .SS \fLaoedev=e!#æ/aoe/\fIshelf\fL.\fIslot\fR
492 This specifies an ATA-over-Ethernet device accessible via the interfaces
493 named in
494 .IR aoeif
495 on AoE
496 .I shelf
497 and
498 .I slot
499 to use as a root device for bootstrapping.
500 .SS \fLramdisk\fIX\fL=\fIsize\fP
501 .SS \fLramdisk\fIX\fL=\fIsize sectorsize\fP
502 .SS \fLramdisk\fIX\fL=\fIaddress size sectorsize\fP
503 This reserves physical memory as a ramdisk that will appear as
504 .IR sd (3)
505 device \fLsdZ\fIX\fR.
506 When the
507 .I address
508 argument is omited or zero, then the ramdisk will be allocated
509 from the top of physical memory.
510 .SS AUDIO
511 .SS \fLaudio\fIX\fL=\fIvalue\fP
512 This defines a sound interface. PCI based audio devices such as
513 Intel HD audio or AC97 are autodetected and do not require any settings.
514 .PP
515 Known types are
516 .TF ess1688
517 .PD
518 .TP
519 .B hda
520 Intel HD audio.
521 .TP
522 .B ac97
523 AC97 based card.
524 .TP
525 .B sb16
526 Sound Blaster 16.
527 .TP
528 .B ess1688
529 A Sound Blaster clone.
530 .PP
531 The DMA channel may be any of 5, 6, or 7.
532 The defaults are
533 .IP
534 .EX
535 port=0x220 irq=7 dma=5
536 .EE
537 .SS UARTS
538 Plan 9 automatically configures COM1 and COM2, if found,
539 as
540 .B eia0
541 (port 0x3F8, IRQ4)
542 and
543 .B eia1
544 (port 0x2F8, IRQ3)
545 respectively.
546 These devices can be disabled by adding a line:
547 .IP
548 .EX
549 eia\fIX\fP=disabled
550 .EE
551 .LP
552 This is typically done in order to reuse the IRQ for
553 another device.
554 .P
555 .PP
556 Additional i8250 (ISA) uarts (uart2 to uart5) can be
557 configured using:
558 .IP
559 .EX
560 uart\fIX\fP=type=isa port=\fIport\fP irq=\fIirq
561 .EE
562 .PP
563 Perle PCI-Fast4, PCI-Fast8, and PCI-Fast16 controllers
564 are automatically detected and need no configuration lines.
565 .PP
566 The line
567 .B serial=type=com
568 can be used to specify settings for a PCMCIA modem.
569 .SS \fLmouseport=\fIvalue\fP
570 This specifies where the mouse is attached.
571 .I Value
572 can be
573 .TP
574 .B ps2
575 the PS2 mouse/keyboard port. The BIOS setup procedure
576 should be used to configure the machine appropriately.
577 .TP
578 .B ps2intellimouse
579 an Intellimouse on the PS2 port.
580 .TP
581 .B 0
582 for COM1
583 .TP
584 .B 1
585 for COM2
586 .SS \fLmodemport=\fIvalue\fP
587 Picks the UART line to call out on.
588 This is used when connecting to a file server over
589 an async line.
590 .I Value
591 is the number of the port.
592 .SS \fLconsole=\fIvalue params\fP
593 This is used to specify the console device.
594 The default
595 .I value
596 is
597 .BR cga ;
598 a number
599 .B 0
600 or
601 .B 1
602 specifies
603 .I COM1
604 or
605 .I COM2
606 respectively.
607 A serial console is initially configured with the
608 .IR uart (3)
609 configuration string
610 .B b9600
611 .B l8
612 .B pn
613 .BR s1 ,
614 specifying 9600 baud,
615 8 bit bytes, no parity, and one stop bit.
616 If
617 .I params
618 is given, it will be used to further
619 configure the uart.
620 Notice that there is no
621 .B =
622 sign in the
623 .I params
624 syntax.
625 For example,
626 .IP
627 .EX
628 console=0 b19200 po
629 .EE
630 .LP
631 would use COM1 at 19,200 baud
632 with odd parity.
633 .LP
634 The value
635 .B net
636 specifies ``netconsole'' which sends console messages as UDP packets over the network.
637 It bypasses the IP stack and writes Ethernet packets directly to the NIC.
638 In this case
639 .I params
640 is mandatory and takes the form
641 .IP
642 \fIsrcip\fR [ \fB!\fIsrcport \fR] [ \fB/\fIdevno \fR] \fB, \fIdstip\fR [ \fB!\fIdstport \fR] [ \fB/\fIdstmac \fR]
643 .LP
644 \fISrcip\fR, \fIsrcport\fR (default 6665), \fIdstip\fR and \fIdstport\fR (default 6666) specify the source IP address, source port, destination IP address and destination port, respectively.
645 \fIDevno\fR (default 0) specifies which NIC to use, a value of \fIn\fR corresponds to NIC at \fL#l\fIn\fR (see
646 .IR ether (3)).
647 \fIDstmac\fR specifies the destination MAC address; broadcast packets are sent if it is unspecified.
648 Note that it is possible, but not recommended, to send packets to a host outside the local network by specifying the MAC address of the gateway as \fIdstmac\fR.
649 Example lines are
650 .IP
651 .EX
652 console=net 192.168.0.4,192.168.0.8
653 console=net 192.168.2.10!1337/1,192.168.2.3!1337/0ea7deadbeef
654 .EE
655 .LP
656 .SS "PC CARD"
657 .SS \fLpccard0=disabled\fP
658 Disable probing for and automatic configuration of PC card controllers.
659 .SS \fLpcmcia\fIX\fL=type=XXX irq=\fIvalue\fP
660 If the default IRQ for the
661 PCMCIA
662 is correct, this entry can be omitted. The value of
663 .B type
664 is ignored.
665 .SS \fLpcmcia0=disabled\fP
666 Disable probing for and automatic configuration of PCMCIA controllers.
667 .SS BOOTING
668 .SS \fLbootfile=\fIvalue\fP
669 This is used to direct the actions of
670 .IR 9boot (8)
671 by naming the file from which to load the kernel in
672 the current BIOS boot device.
673 .SS \fLbootargs=\fIvalue\fP
674 The
675 .I value
676 of this variable is passed to
677 .IR boot (8)
678 by the kernel as the name of the root file system to
679 automatically mount and boot into.
680 It is typically used to specify additional arguments to
681 pass to
682 .IR cwfs (4)
683 or
684 .IR ipconfig (8).
685 For example, if the system is to run from a local
686 .IR cwfs (4)
687 partition, the definition might read
688 .BR bootargs=local!/dev/sdC0/fscache .
689 See
690 .IR boot (8)
691 for more.
692 .SS \fLnobootprompt=\fIvalue\fP
693 Suppress the
694 .L bootargs
695 prompt and use
696 .I value
697 as the answer instead.
698 .SS \fLrootdir=\fB/root/\fIdir\fP
699 .SS \fLrootspec=\fIspec\fP
700 Changes the mount arguments for the root file server
701 that was specified by
702 .I bootargs
703 above.
704 By changing
705 .I dir
706 in
707 .BR $rootdir ,
708 a different sub-directory on the root file server
709 can be used as the system root. see
710 .IR boot (8)
711 for details.
712 .SS \fLuser=\fIvalue\fP
713 Suppress the
714 .L "user"
715 prompt and use
716 .I value
717 as the answer instead.
718 .SS \fLservice=\fIvalue\fP
719 Changes the systems default role. Possible
720 settings for
721 .I value
722 are
723 .B cpu
724 and
725 .B terminal.
726 .SS \fLdebugfactotum=\fP
727 Causes
728 .IR boot (8)
729 to start
730 .I factotum
731 with the
732 .B -p
733 option, so that it can be debugged.
734 .SS \fLcfs=\fIvalue\fP
735 This gives the name of the file holding the disk partition
736 for the cache file system,
737 .IR cfs (4).
738 Extending the
739 .B bootargs
740 example, one would write
741 .BR cfs=#S/sdC0/cache .
742 .SS \fLbootdisk=\fIvalue\fP
743 This deprecated variable was used to specify the disk used by
744 the cache file system and other disk-resident services.
745 It is superseded by
746 .B bootargs
747 and
748 .BR cfs .
749 .SS \fLfs=\fIaddress\fP
750 .SS \fLauth=\fIaddress\fP
751 .SS \fLsecstore=\fIaddress\fP
752 These specify the network address (IP or domain name)
753 of the file, authentication and secstore server
754 to use when mounting a network-provided root file system.
755 When not specified, then these settings are determined via DHCP.
756 When
757 .B secstore
758 is not specified, then the authentication server is used.
759 .SS PROCESSOR
760 .SS \fL*e820=\fItype \fB0x\fIstart \fB0x\fIend ...\fP
761 This variable is automatically generated by the boot loader (see
762 .IR 9boot (8))
763 by doing a BIOS E820 memory scan while still in realmode and
764 passed to the kernel. The format is a unordered list of
765 decimal region
766 .I type
767 and hexadecimal 64-bit
768 .I start
769 and
770 .I end
771 addresses of the area.
772 .SS \fL*maxmem=\fIvalue\fP
773 This defines the maximum physical address that the system will scan when sizing memory.
774 By default the PC operating system will scan up to 3.75 gigabytes
775 (0xF0000000, the base of kernel virtual address space), but setting
776 .B *maxmem
777 will limit the scan.
778 .B *maxmem
779 must be less than 3.75 gigabytes.
780 This variable is not consulted if using the E820 memory map.
781 .SS \fL*kernelpercent=\fIvalue\fP
782 This defines what percentage of available memory is reserved for the kernel allocation pool.
783 The remainder is left for user processes. The default
784 .I value
785 is
786 .B 30
787 on CPU servers,
788 .B 60
789 on terminals with less than 16MB of memory,
790 and
791 .B 40
792 on terminals with memories of 16MB or more.
793 Terminals use more kernel memory because
794 .IR draw (3)
795 maintains its graphic images in kernel memory.
796 This deprecated option is rarely necessary in newer kernels.
797 .SS \fL*imagemaxmb=\fIvalue\fP
798 This limits the maximum amount of memory (in megabytes) the graphics
799 image memory pool can grow. The default is unlimited for terminals
800 and cpu servers.
801 .SS \fL*nomce=\fIvalue\fP
802 If machine check exceptions are supported by the processor,
803 then they are enabled by default.
804 Setting this variable to
805 .B 1
806 causes them to be disabled even when available.
807 .SS \fL*nomp=\fP
808 A multiprocessor machine will enable all processors by default.
809 Setting
810 .B *nomp
811 restricts the kernel to starting only one processor and using the
812 traditional interrupt controller.
813 .SS \fL*ncpu=\fIvalue\fP
814 Setting
815 .B *ncpu
816 restricts the kernel to starting at most
817 .I value
818 processors.
819 .SS \fL*apicdebug=\fP
820 Prints a summary of the multiprocessor APIC interrupt configuration.
821 .SS \fL*nomsi=\fP
822 Disables message signaled interrupts.
823 .SS \fL*notsc=\fP
824 Disables the use of the per processor timestamp counter registers
825 as high resolution clock.
826 .SS \fL*pcimaxbno=value\fP
827 This puts a limit on the maximum bus number probed
828 on a PCI bus (default 7).
829 For example, a
830 .I value
831 of 1 should suffice on a 'standard' motherboard with an AGP slot.
832 This, and
833 .B *pcimaxdno
834 below are rarely used and only on troublesome or suspect hardware.
835 .SS \fL*pcimaxdno=\fIvalue\fP
836 This puts a limit on the maximum device number probed
837 on a PCI bus (default 31).
838 .SS \fL*nopcirouting=\fP
839 Disable pci routing during boot. May solve interrupt routing
840 problems on certain machines.
841 .SS \fL*pcihinv=\fP
842 Prints a summary of the detected PCI busses and devices.
843 .SS \fL*nodumpstack=\fP
844 Disable printing a stack dump on panic.
845 Useful if there is only a limited cga screen available,
846 otherwise the textual information about the panic may scroll off.
847 .\" .SS \fL*nobios=\fP
848 .\" what does this do? something with pci
849 .SS \fLioexclude=\fIvalue\fP
850 Specifies a list of ranges of I/O ports to exclude from use by drivers.
851 Ranges are inclusive on both ends and separated by commas.
852 For example:
853 .EX
854  ioexclude=0x330-0x337,0x430-0x43F
855 .EE
856 .SS \fLumbexclude=\fIvalue\fP
857 Specifies a list of ranges of UMB to exclude from use by drivers.
858 Ranges are inclusive on both ends and separated by commas.
859 For example:
860 .EX
861  umbexclude=0xD1800-0xD3FFF
862 .EE
863 .SS \fL*acpi=\fIvalue\fP
864 The presence of this option enables ACPI and the export of the
865 .B #P/acpitbls
866 file in
867 .IR arch (3)
868 device. In multiprocessor mode, the kernel will use the ACPI
869 tables to configure APIC interrupts unless a
870 .I value
871 of
872 .B 0
873 is specified.
874 .SS \fLapm0=\fP
875 This enables the ``advanced power management'' interface
876 as described in
877 .IR apm (3)
878 and
879 .IR apm (8).
880 The main feature of the interface is the ability to watch
881 battery life (see
882 .IR stats (8)).
883 It is not on by default because it causes problems on some laptops.
884 .SS USB
885 .SS \fL*nousbprobe=\fP
886 Disable USB host controller detection.
887 .SS \fL*nousbohci=\fP
888 .SS \fL*nousbuhci=\fP
889 .SS \fL*nousbehci=\fP
890 .SS \fL*nousbxhci=\fP
891 Disable specific USB host controller types.
892 .SS \fLnousbrc=\fP
893 Disable
894 .IR nusbrc (8)
895 startup at boot time.
896 .SS \fLnousbhname=\fP
897 When defined,
898 .IR nusbrc (8)
899 will use the dynamically assigned usb device address to name
900 usb devices instead of the device unique name.
901 .SS VIDEO
902 .SS \fLmonitor=\fIvalue\fP
903 .SS \fLvgasize=\fIvalue\fP
904 These are used not by the kernel but by
905 .I termrc
906 (see
907 .IR cpurc (8))
908 when starting
909 .IR vga (8).
910 If
911 .I value
912 is set to
913 .B ask
914 then the user is prompted for a choice on boot.
915 .SS \fL*bootscreen=\fIvalue\fP
916 This is used by the kernel to attach a pre-initialized
917 linear framebuffer that was setup by the bootloader
918 or firmware.
919 The
920 .I value
921 has four space separated fields: the resolution and bitdepth
922 of the screen, the color channel descriptor, the physical
923 address of the framebuffer and a optional aperture size.
924 .EX
925  *bootscreen=800x600x32 x8r8g8b8 0x80000000 0x001d4c00
926 .EE
927 .SS \fL*dpms=\fIvalue\fP
928 This is used to specify the screen blanking behavior of the MGA4xx
929 video driver.
930 Values are
931 .BR standby ,
932 .BR suspend ,
933 and
934 .BR off .
935 The first two specify differing levels of power saving;
936 the third turns the monitor off completely.
937 .SS NVRAM
938 .SS \fLnvram=\fIfile\fP
939 .SS \fLnvrlen=\fIlength\fP
940 .SS \fLnvroff=\fIoffset\fP
941 This is used to specify an nvram device and optionally the length of the ram
942 and read/write offset to use.
943 These values are consulted by
944 .I readnvram
945 (see
946 .IR authsrv (2)).
947 The most common use of the nvram is to hold a
948 .IR secstore (1)
949 password for use by
950 .IR factotum (4).
951 .SS \fLnvr=\fIvalue\fP
952 This is used by the WORM file server kernel to locate a file holding information
953 to configure the file system.
954 The file cannot live on a SCSI disk.
955 The default is
956 .B fd!0!plan9.nvr
957 (sic),
958 unless
959 .B bootfile
960 is set, in which case it is
961 .B plan9.nvr
962 on the same disk as
963 .BR bootfile .
964 The syntax is either
965 .BI fd! unit ! name
966 or
967 .BI hd! unit ! name
968 where
969 .I unit
970 is the numeric unit id.
971 This variant syntax is a vestige of the file server kernel's origins.
972 .SH EXAMPLES
973 .PP
974 A representative
975 .BR plan9.ini :
976 .IP
977 .EX
978 % cat /n/9fat:/plan9.ini
979 ether0=type=3C509
980 mouseport=ps2
981 modemport=1
982 serial0=type=generic port=0x3E8 irq=5
983 monitor=445x
984 vgasize=1600x1200x8
985 bootfile=/386/9pc
986 %
987 .EE
988 .SH "SEE ALSO"
989 .IR 9boot (8),
990 .IR booting (8),
991 .IR boot (8)