1June 1999 Kernel Parameters v2.2.9 2 ~~~~~~~~~~~~~~~~~ 3 4The following is a consolidated list of the kernel parameters as defined 5in the file init/main.c and sorted into English Dictionary order (defined 6as ignoring all punctuation and sorting digits before letters in a case 7insensitive manner), and with descriptions where known. 8 9The text in square brackets at the beginning of the description state the 10restrictions on the kernel for the said kernel parameter to be valid. The 11restrictions referred to are that the relevant option is valid if: 12 13 APIC APIC support is enabled. 14 APM Advanced Power Management support is enabled. 15 AX25 Appropriate AX.25 support is enabled. 16 CD Appropriate CD support is enabled. 17 EIDE EIDE/ATAPI support is enabled. 18 FB The frame buffer device is enabled. 19 HW Appropriate hardware is enabled. 20 ISDN Appropriate ISDN support is enabled. 21 JOY Appropriate joystick support is enabled. 22 LPT Printer support is enabled. 23 MCA MCA bus support is enabled. 24 MDA The MDA console is enabled. 25 MOUSE Appropriate mouse support is enabled. 26 NET Appropriate network support is enabled. 27 NFS Appropriate NFS support is enabled. 28 PARIDE The ParIDE subsystem is enabled. 29 PCI PCI bus support is enabled. 30 PCMCIA The PCMCIA subsystem is enabled. 31 PNP Plug & Play support is enabled. 32 PS2 Appropriate PS/2 support is enabled. 33 RAM RAMdisc support is enabled. 34 SCSI Appropriate SCSI support is enabled. 35 SERIAL Serial support is enabled. 36 SMP The kernel is an SMP kernel. 37 SOUND Appropriate sound system support is enabled. 38 VGA The VGA console has been enabled. 39 VT Virtual terminal support is enabled. 40 XT IBM PC/XT MFM hard disk support is enabled. 41 42In addition, the following text indicates that the option: 43 44 BUGS= Relates to possible processor bugs on the said processor. 45 KNL Is a kernel start-up parameter. 46 47Note that ALL kernel parameters listed below are CASE SENSITIVE, and that 48a trailing = on the name of any parameter states that that parameter will 49be entered as an environment variable, whereas its absence indicates that 50it will appear as a kernel argument readable via /proc/cmdline by programs 51running once the system is up. 52 53 53c7xx= [HW,SCSI] Amiga SCSI controllers 54 55 adb_buttons= [HW,MOUSE] 56 57 advansys= [HW,SCSI] 58 59 aha152x= [HW,SCSI] 60 61 aha1542= [HW,SCSI] 62 63 aic7xxx= [HW,SCSI] 64 65 AM53C974= [HW,SCSI] 66 67 apm= [APM] Advanced Power Management. 68 69 arcrimi= [HW,NET] 70 71 ataflop= [HW, M68k] 72 73 atamouse= [HW,MOUSE] Atari Mouse. 74 75 atascsi= [HW,SCSI] Atari SCSI. 76 77 aztcd= [HW,CD] Aztec CD driver. 78 79 baycom_par= [HW,AX25] BayCom Parallel Port AX.25 Modem. 80 81 baycom_ser_fdx= [HW,AX25] BayCom Serial Port AX.25 Modem in Full 82 Duplex Mode. 83 84 baycom_ser_hdx= [HW,AX25] BayCom Serial Port AX.25 Modem in Half 85 Duplex Mode. 86 87 bmouse= [HW,MOUSE,PS2] Bus mouse. 88 89 BusLogic= [HW,SCSI] 90 91 cdu31a= [HW,CD] 92 93 cm206= [HW,CD] 94 95 com20020= [HW,NET] 96 97 com90io= [HW,NET] 98 99 com90xx= [HW,NET] 100 101 console= [KNL] output console + comm spec (speed, control, parity) 102 103 cyclades= [HW,SERIAL] Cyclades multi-serial port adapter. 104 105 debug [KNL] Enable kernel debugging (events log level). 106 107 decnet= [HW,NET] 108 109 digi= [HW,SERIAL] io parameters + enable/disable command 110 111 digiepca= [HW,SERIAL] 112 113 dmascc= [HW,AX25,SERIAL] AX.25 Z80SCC driver with DMA 114 support available. 115 116 dmasound= [HW,SOUND] (sound subsystem buffers) 117 118 dtc3181e= [HW,SCSI] 119 120 eata= [HW,SCSI] 121 122 eda= [HW,PS2] 123 124 edb= [HW,PS2] 125 126 ether= [HW,NET] Ethernet cards parameters (iomem,irq,dev_name). 127 128 fd_mcs= [HW,SCSI] 129 130 fdomain= [HW,SCSI] 131 132 floppy= [HW] 133 134 ftape= [HW] Floppy Tape subsystem debugging options. 135 136 gdth= [HW,SCSI] 137 138 gscd= [HW,CD] 139 140 gvp11= [HW,SCSI] 141 142 hd= [EIDE] (E)IDE hard drive subsystem 143 geometry (Cyl/heads/sectors) or tune parameters. 144 145 hfmodem= [HW,AX25] 146 147 HiSax= [HW,ISDN] 148 149 hisax= [HW,ISDN] 150 151 ibmmcascsi= [HW,MCA,SCSI] IBM MicroChannel SCSI adapter. 152 153 icn= [HW,ISDN] 154 155 ide?= [HW] (E)IDE subsystem : config (iomem/irq), tuning or 156 debugging (serialize,reset,no{dma,tune,probe}) or 157 chipset specific parameters 158 159 idebus= [HW] (E)IDE subsystem : VLB/PCI bus speed 160 161 in2000= [HW,SCSI] 162 163 init= [KNL] 164 165 initrd= [KNL] initial ramdisk path 166 167 ip= [PNP] 168 169 isp16= [HW,CD] 170 171 js_14= [HW,JOY] 172 173 js_am= [HW,JOY] 174 175 js_an= [HW,JOY] 176 177 js_as= [HW.JOY] 178 179 js_console= [HW,JOY] 180 181 js_console2= [HW,JOY] 182 183 js_console3= [HW,JOY] 184 185 js_db9= [HW,JOY] 186 187 js_db9_2= [HW,JOY] 188 189 js_db9_3= [HW,JOY] 190 191 js_tg= [HW,JOY] 192 193 js_tg_2= [HW,JOY] 194 195 js_tg_3= [HW,JOY] 196 197 kbd-reset [VT] 198 199 load_ramdisk= [RAM] initrd loading boolean 200 201 lp= [LPT] Parallel Printer. 202 203 ltpc= [HW] 204 205 mac5380= [HW,SCSI] 206 207 maxcpus= [SMP] States the maximum number of processors that 208 an SMP kernel should make use of. 209 210 max_scsi_luns= [SCSI] 211 212 mca-pentium [BUGS=ix86] 213 214 mcd= [HW,CD] 215 216 mcdx= [HW,CD] 217 218 md= [HW] RAID subsystems devices and level 219 220 mdacon= [MDA] 221 222 msmouse= [HW,MOUSE] Microsoft Mouse. 223 224 ncr5380= [HW,SCSI] 225 226 ncr53c400= [HW,SCSI] 227 228 ncr53c400a= [HW,SCSI] 229 230 ncr53c406a= [HW,SCSI] 231 232 ncr53c8xx= [HW,SCSI] 233 234 nfsaddrs= [NFS] 235 236 nfsroot= [NFS] 237 238 nmi_watchdog= [KNL, BUGS=ix86] debugging features for SMP kernels 239 240 no387 [BUGS=ix86] Tells the kernel to use the 387 maths 241 emulation library even if a 387 maths coprocessor 242 is present. 243 244 noapic [SMP,APIC] Tells the kernel not to make use of any 245 APIC that may be present on the system. 246 247 noasync [HW, M68K] Disables async and sync negotiation for all devices. 248 249 nodisconnect [HW,SCSI, M68K] Disables SCSI disconnects. 250 251 no-halt [BUGS=ix86] 252 253 noinitrd [RAM] Tells the kernel not to load any configured 254 initial ramdisc. 255 256 no-scroll [VGA] 257 258 nosmp [SMP] Tells an SMP kernel to act as a UP kernel. 259 260 nosync [HW, M68K] Disables sync negotiation for all devices. 261 262 optcd= [HW,CD] 263 264 panic= 265 266 parport= [HW,LP] 267 268 pas16= [HW,SCSI] 269 270 pcbit= [HW,ISDN] 271 272 pcd. [PARIDE] 273 274 pci= [PCI] 275 276 pd. [PARIDE] 277 278 pf. [PARIDE] 279 280 pg. [PARIDE] 281 282 pirq= [SMP,APIC] mp-table 283 284 plip= [LP,NET] Parallel port network link. 285 286 profile= 287 288 prompt_ramdisk= [RAM] Whether to prompt for ramdisk before loading 289 its contents into memory. 290 291 pt. [PARIDE] 292 293 ramdisk= [RAM] 294 295 ramdisk_size= [RAM] 296 297 ramdisk_start= [RAM] offset of the initrd image when cohabiting with 298 a kernel image on a floppy 299 300 reboot= [BUGS=ix86] 301 302 reserve= 303 304 riscom8= [HW,SERIAL] multi-port serial driver (io parameters) 305 306 ro [KNL] Mount root device read-only on boot. 307 308 root= 309 310 rw [KNL] Mount root device read-write on boot. 311 312 sbpcd= [HW,CD] Soundblaster CD adapter. 313 314 scsi_logging= [SCSI] 315 316 sjcd= [HW,CD] 317 318 sonycd535= [HW,CD] 319 320 sound= [SOUND] 321 322 soundmodem= [HW,AX25,SOUND] Sound cards used as AX.25 modems. 323 324 specialix= [HW,SERIAL] Specialix multi-serial port adapter. 325 326 st= [HW] SCSI tape parameters (buffers, ..) 327 328 st0x= [HW,SCSI] 329 330 stram_swap= [HW] 331 332 switches= [HW, M68K] 333 334 sym53c416= [HW,SCSI] 335 336 sym53c8xx= [HW,SCSI] 337 338 t128= [HW,SCSI] 339 340 tmc8xx= [HW,SCSI] 341 342 tmscsim= [HW,SCSI] 343 344 tp720= [HW,PS2] 345 346 u14-34f= [HW,SCSI] 347 348 video= [FB] 349 350 wd33c93= [HW,SCSI] 351 352 wd7000= [HW,SCSI] 353 354 wdt= [HW] 355 356 xd= [HW,XT] Original XT 8bit disk controllers 357 358 xd_geo= [HW,XT] 359