June 1999 Kernel Parameters v2.2.9 ~~~~~~~~~~~~~~~~~ The following is a consolidated list of the kernel parameters as defined in the file init/main.c and sorted into English Dictionary order (defined as ignoring all punctuation and sorting digits before letters in a case insensitive manner), and with descriptions where known. The text in square brackets at the beginning of the description state the restrictions on the kernel for the said kernel parameter to be valid. The restrictions referred to are that the relevant option is valid if: APIC APIC support is enabled. APM Advanced Power Management support is enabled. AX25 Appropriate AX.25 support is enabled. CD Appropriate CD support is enabled. EIDE EIDE/ATAPI support is enabled. FB The frame buffer device is enabled. HW Appropriate hardware is enabled. ISDN Appropriate ISDN support is enabled. JOY Appropriate joystick support is enabled. LPT Printer support is enabled. MCA MCA bus support is enabled. MDA The MDA console is enabled. MOUSE Appropriate mouse support is enabled. NET Appropriate network support is enabled. NFS Appropriate NFS support is enabled. PARIDE The ParIDE subsystem is enabled. PCI PCI bus support is enabled. PCMCIA The PCMCIA subsystem is enabled. PNP Plug & Play support is enabled. PS2 Appropriate PS/2 support is enabled. RAM RAMdisc support is enabled. SCSI Appropriate SCSI support is enabled. SERIAL Serial support is enabled. SMP The kernel is an SMP kernel. SOUND Appropriate sound system support is enabled. VGA The VGA console has been enabled. VT Virtual terminal support is enabled. XT IBM PC/XT MFM hard disk support is enabled. In addition, the following text indicates that the option: BUGS= Relates to possible processor bugs on the said processor. KNL Is a kernel start-up parameter. Note that ALL kernel parameters listed below are CASE SENSITIVE, and that a trailing = on the name of any parameter states that that parameter will be entered as an environment variable, whereas its absence indicates that it will appear as a kernel argument readable via /proc/cmdline by programs running once the system is up. 53c7xx= [HW,SCSI] Amiga SCSI controllers adb_buttons= [HW,MOUSE] advansys= [HW,SCSI] aha152x= [HW,SCSI] aha1542= [HW,SCSI] aic7xxx= [HW,SCSI] AM53C974= [HW,SCSI] apm= [APM] Advanced Power Management. arcrimi= [HW,NET] ataflop= [HW, M68k] atamouse= [HW,MOUSE] Atari Mouse. atascsi= [HW,SCSI] Atari SCSI. aztcd= [HW,CD] Aztec CD driver. baycom_par= [HW,AX25] BayCom Parallel Port AX.25 Modem. baycom_ser_fdx= [HW,AX25] BayCom Serial Port AX.25 Modem in Full Duplex Mode. baycom_ser_hdx= [HW,AX25] BayCom Serial Port AX.25 Modem in Half Duplex Mode. bmouse= [HW,MOUSE,PS2] Bus mouse. BusLogic= [HW,SCSI] cdu31a= [HW,CD] cm206= [HW,CD] com20020= [HW,NET] com90io= [HW,NET] com90xx= [HW,NET] console= [KNL] output console + comm spec (speed, control, parity) cyclades= [HW,SERIAL] Cyclades multi-serial port adapter. debug [KNL] Enable kernel debugging (events log level). decnet= [HW,NET] digi= [HW,SERIAL] io parameters + enable/disable command digiepca= [HW,SERIAL] dmascc= [HW,AX25,SERIAL] AX.25 Z80SCC driver with DMA support available. dmasound= [HW,SOUND] (sound subsystem buffers) dtc3181e= [HW,SCSI] eata= [HW,SCSI] eda= [HW,PS2] edb= [HW,PS2] ether= [HW,NET] Ethernet cards parameters (iomem,irq,dev_name). fd_mcs= [HW,SCSI] fdomain= [HW,SCSI] floppy= [HW] ftape= [HW] Floppy Tape subsystem debugging options. gdth= [HW,SCSI] gscd= [HW,CD] gvp11= [HW,SCSI] hd= [EIDE] (E)IDE hard drive subsystem geometry (Cyl/heads/sectors) or tune parameters. hfmodem= [HW,AX25] HiSax= [HW,ISDN] hisax= [HW,ISDN] ibmmcascsi= [HW,MCA,SCSI] IBM MicroChannel SCSI adapter. icn= [HW,ISDN] ide?= [HW] (E)IDE subsystem : config (iomem/irq), tuning or debugging (serialize,reset,no{dma,tune,probe}) or chipset specific parameters idebus= [HW] (E)IDE subsystem : VLB/PCI bus speed in2000= [HW,SCSI] init= [KNL] initrd= [KNL] initial ramdisk path ip= [PNP] isp16= [HW,CD] js_14= [HW,JOY] js_am= [HW,JOY] js_an= [HW,JOY] js_as= [HW.JOY] js_console= [HW,JOY] js_console2= [HW,JOY] js_console3= [HW,JOY] js_db9= [HW,JOY] js_db9_2= [HW,JOY] js_db9_3= [HW,JOY] js_tg= [HW,JOY] js_tg_2= [HW,JOY] js_tg_3= [HW,JOY] kbd-reset [VT] load_ramdisk= [RAM] initrd loading boolean lp= [LPT] Parallel Printer. ltpc= [HW] mac5380= [HW,SCSI] maxcpus= [SMP] States the maximum number of processors that an SMP kernel should make use of. max_scsi_luns= [SCSI] mca-pentium [BUGS=ix86] mcd= [HW,CD] mcdx= [HW,CD] md= [HW] RAID subsystems devices and level mdacon= [MDA] msmouse= [HW,MOUSE] Microsoft Mouse. ncr5380= [HW,SCSI] ncr53c400= [HW,SCSI] ncr53c400a= [HW,SCSI] ncr53c406a= [HW,SCSI] ncr53c8xx= [HW,SCSI] nfsaddrs= [NFS] nfsroot= [NFS] nmi_watchdog= [KNL, BUGS=ix86] debugging features for SMP kernels no387 [BUGS=ix86] Tells the kernel to use the 387 maths emulation library even if a 387 maths coprocessor is present. noapic [SMP,APIC] Tells the kernel not to make use of any APIC that may be present on the system. noasync [HW, M68K] Disables async and sync negotiation for all devices. nodisconnect [HW,SCSI, M68K] Disables SCSI disconnects. no-halt [BUGS=ix86] noinitrd [RAM] Tells the kernel not to load any configured initial ramdisc. no-scroll [VGA] nosmp [SMP] Tells an SMP kernel to act as a UP kernel. nosync [HW, M68K] Disables sync negotiation for all devices. optcd= [HW,CD] panic= parport= [HW,LP] pas16= [HW,SCSI] pcbit= [HW,ISDN] pcd. [PARIDE] pci= [PCI] pd. [PARIDE] pf. [PARIDE] pg. [PARIDE] pirq= [SMP,APIC] mp-table plip= [LP,NET] Parallel port network link. profile= prompt_ramdisk= [RAM] Whether to prompt for ramdisk before loading its contents into memory. pt. [PARIDE] ramdisk= [RAM] ramdisk_size= [RAM] ramdisk_start= [RAM] offset of the initrd image when cohabiting with a kernel image on a floppy reboot= [BUGS=ix86] reserve= riscom8= [HW,SERIAL] multi-port serial driver (io parameters) ro [KNL] Mount root device read-only on boot. root= rw [KNL] Mount root device read-write on boot. sbpcd= [HW,CD] Soundblaster CD adapter. scsi_logging= [SCSI] sjcd= [HW,CD] sonycd535= [HW,CD] sound= [SOUND] soundmodem= [HW,AX25,SOUND] Sound cards used as AX.25 modems. specialix= [HW,SERIAL] Specialix multi-serial port adapter. st= [HW] SCSI tape parameters (buffers, ..) st0x= [HW,SCSI] stram_swap= [HW] switches= [HW, M68K] sym53c416= [HW,SCSI] sym53c8xx= [HW,SCSI] t128= [HW,SCSI] tmc8xx= [HW,SCSI] tmscsim= [HW,SCSI] tp720= [HW,PS2] u14-34f= [HW,SCSI] video= [FB] wd33c93= [HW,SCSI] wd7000= [HW,SCSI] wdt= [HW] xd= [HW,XT] Original XT 8bit disk controllers xd_geo= [HW,XT]