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This file describes the floppy driver

Guest on 31st July 2022 01:18:01 AM

  1. This file describes the floppy driver.
  2.  
  3. FAQ list:
  4. =========
  5.  
  6.  A FAQ list may be found in the fdutils package (see below), and also
  7. at <http://fdutils.linux.lu/faq.html>.
  8.  
  9.  
  10. LILO configuration options (Thinkpad users, read this)
  11. ======================================================
  12.  
  13.  The floppy driver is configured using the 'floppy=' option in
  14. lilo. This option can be typed at the boot prompt, or entered in the
  15. lilo configuration file.
  16.  
  17.  Example: If your kernel is called linux-2.6.9, type the following line
  18. at the lilo boot prompt (if you have a thinkpad):
  19.  
  20.  linux-2.6.9 floppy=thinkpad
  21.  
  22. You may also enter the following line in /etc/lilo.conf, in the description
  23. of linux-2.6.9:
  24.  
  25.  append = "floppy=thinkpad"
  26.  
  27.  Several floppy related options may be given, example:
  28.  
  29.  linux-2.6.9 floppy=daring floppy=two_fdc
  30.  append = "floppy=daring floppy=two_fdc"
  31.  
  32.  If you give options both in the lilo config file and on the boot
  33. prompt, the option strings of both places are concatenated, the boot
  34. prompt options coming last. That's why there are also options to
  35. restore the default behavior.
  36.  
  37.  
  38. Module configuration options
  39. ============================
  40.  
  41.  If you use the floppy driver as a module, use the following syntax:
  42. modprobe floppy floppy="<options>"
  43.  
  44. Example:
  45.  modprobe floppy floppy="omnibook messages"
  46.  
  47.  If you need certain options enabled every time you load the floppy driver,
  48. you can put:
  49.  
  50.  options floppy floppy="omnibook messages"
  51.  
  52. in a configuration file in /etc/modprobe.d/.
  53.  
  54.  
  55.  The floppy driver related options are:
  56.  
  57.  floppy=asus_pci
  58.         Sets the bit mask to allow only units 0 and 1. (default)
  59.  
  60.  floppy=daring
  61.         Tells the floppy driver that you have a well behaved floppy controller.
  62.         This allows more efficient and smoother operation, but may fail on
  63.         certain controllers. This may speed up certain operations.
  64.  
  65.  floppy=0,daring
  66.         Tells the floppy driver that your floppy controller should be used
  67.         with caution.
  68.  
  69.  floppy=one_fdc
  70.         Tells the floppy driver that you have only one floppy controller.
  71.         (default)
  72.  
  73.  floppy=two_fdc
  74.  floppy=<address>,two_fdc
  75.         Tells the floppy driver that you have two floppy controllers.
  76.         The second floppy controller is assumed to be at <address>.
  77.         This option is not needed if the second controller is at address
  78.         0x370, and if you use the 'cmos' option.
  79.  
  80.  floppy=thinkpad
  81.         Tells the floppy driver that you have a Thinkpad. Thinkpads use an
  82.         inverted convention for the disk change line.
  83.  
  84.  floppy=0,thinkpad
  85.         Tells the floppy driver that you don't have a Thinkpad.
  86.  
  87.  floppy=omnibook
  88.  floppy=nodma
  89.         Tells the floppy driver not to use Dma for data transfers.
  90.         This is needed on HP Omnibooks, which don't have a workable
  91.         DMA channel for the floppy driver. This option is also useful
  92.         if you frequently get "Unable to allocate DMA memory" messages.
  93.         Indeed, dma memory needs to be continuous in physical memory,
  94.         and is thus harder to find, whereas non-dma buffers may be
  95.         allocated in virtual memory. However, I advise against this if
  96.         you have an FDC without a FIFO (8272A or 82072). 82072A and
  97.         later are OK. You also need at least a 486 to use nodma.
  98.         If you use nodma mode, I suggest you also set the FIFO
  99.         threshold to 10 or lower, in order to limit the number of data
  100.         transfer interrupts.
  101.  
  102.         If you have a FIFO-able FDC, the floppy driver automatically
  103.         falls back on non DMA mode if no DMA-able memory can be found.
  104.         If you want to avoid this, explicitly ask for 'yesdma'.
  105.  
  106.  floppy=yesdma
  107.         Tells the floppy driver that a workable DMA channel is available.
  108.         (default)
  109.  
  110.  floppy=nofifo
  111.         Disables the FIFO entirely. This is needed if you get "Bus
  112.         master arbitration error" messages from your Ethernet card (or
  113.         from other devices) while accessing the floppy.
  114.  
  115.  floppy=usefifo
  116.         Enables the FIFO. (default)
  117.  
  118.  floppy=<threshold>,fifo_depth
  119.         Sets the FIFO threshold. This is mostly relevant in DMA
  120.         mode. If this is higher, the floppy driver tolerates more
  121.         interrupt latency, but it triggers more interrupts (i.e. it
  122.         imposes more load on the rest of the system). If this is
  123.         lower, the interrupt latency should be lower too (faster
  124.         processor). The benefit of a lower threshold is less
  125.         interrupts.
  126.  
  127.         To tune the fifo threshold, switch on over/underrun messages
  128.         using 'floppycontrol --messages'. Then access a floppy
  129.         disk. If you get a huge amount of "Over/Underrun - retrying"
  130.         messages, then the fifo threshold is too low. Try with a
  131.         higher value, until you only get an occasional Over/Underrun.
  132.         It is a good idea to compile the floppy driver as a module
  133.         when doing this tuning. Indeed, it allows to try different
  134.         fifo values without rebooting the machine for each test. Note
  135.         that you need to do 'floppycontrol --messages' every time you
  136.         re-insert the module.
  137.  
  138.         Usually, tuning the fifo threshold should not be needed, as
  139.         the default (0xa) is reasonable.
  140.  
  141.  floppy=<drive>,<type>,cmos
  142.         Sets the CMOS type of <drive> to <type>. This is mandatory if
  143.         you have more than two floppy drives (only two can be
  144.         described in the physical CMOS), or if your BIOS uses
  145.         non-standard CMOS types. The CMOS types are:
  146.  
  147.                 0 - Use the value of the physical CMOS
  148.                 1 - 5 1/4 DD
  149.                 2 - 5 1/4 HD
  150.                 3 - 3 1/2 DD
  151.                 4 - 3 1/2 HD
  152.                 5 - 3 1/2 ED
  153.                 6 - 3 1/2 ED
  154.                16 - unknown or not installed
  155.  
  156.         (Note: there are two valid types for ED drives. This is because 5 was
  157.         initially chosen to represent floppy *tapes*, and 6 for ED drives.
  158.         AMI ignored this, and used 5 for ED drives. That's why the floppy
  159.         driver handles both.)
  160.  
  161.  floppy=unexpected_interrupts
  162.         Print a warning message when an unexpected interrupt is received.
  163.         (default)
  164.  
  165.  floppy=no_unexpected_interrupts
  166.  floppy=L40SX
  167.         Don't print a message when an unexpected interrupt is received. This
  168.         is needed on IBM L40SX laptops in certain video modes. (There seems
  169.         to be an interaction between video and floppy. The unexpected
  170.         interrupts affect only performance, and can be safely ignored.)
  171.  
  172.  floppy=broken_dcl
  173.         Don't use the disk change line, but assume that the disk was
  174.         changed whenever the device node is reopened. Needed on some
  175.         boxes where the disk change line is broken or unsupported.
  176.         This should be regarded as a stopgap measure, indeed it makes
  177.         floppy operation less efficient due to unneeded cache
  178.         flushings, and slightly more unreliable. Please verify your
  179.         cable, connection and jumper settings if you have any DCL
  180.         problems. However, some older drives, and also some laptops
  181.         are known not to have a DCL.
  182.  
  183.  floppy=debug
  184.         Print debugging messages.
  185.  
  186.  floppy=messages
  187.         Print informational messages for some operations (disk change
  188.         notifications, warnings about over and underruns, and about
  189.         autodetection).
  190.  
  191.  floppy=silent_dcl_clear
  192.         Uses a less noisy way to clear the disk change line (which
  193.         doesn't involve seeks). Implied by 'daring' option.
  194.  
  195.  floppy=<nr>,irq
  196.         Sets the floppy IRQ to <nr> instead of 6.
  197.  
  198.  floppy=<nr>,dma
  199.         Sets the floppy DMA channel to <nr> instead of 2.
  200.  
  201.  floppy=slow
  202.         Use PS/2 stepping rate:
  203.          " PS/2 floppies have much slower step rates than regular floppies.
  204.            It's been recommended that take about 1/4 of the default speed
  205.            in some more extreme cases."
  206.  
  207.  
  208. Supporting utilities and additional documentation:
  209. ==================================================
  210.  
  211.  Additional parameters of the floppy driver can be configured at
  212. runtime. Utilities which do this can be found in the fdutils package.
  213. This package also contains a new version of mtools which allows to
  214. access high capacity disks (up to 1992K on a high density 3 1/2 disk!).
  215. It also contains additional documentation about the floppy driver.
  216.  
  217. The latest version can be found at fdutils homepage:
  218.  http://fdutils.linux.lu
  219.  
  220. The fdutils releases can be found at:
  221.  http://fdutils.linux.lu/download.html
  222.  http://www.tux.org/pub/knaff/fdutils/
  223.  ftp://metalab.unc.edu/pub/Linux/utils/disk-management/
  224.  
  225. Reporting problems about the floppy driver
  226. ==========================================
  227.  
  228.  If you have a question or a bug report about the floppy driver, mail
  229. me at Alain.Knaff@poboxes.com . If you post to Usenet, preferably use
  230. comp.os.linux.hardware. As the volume in these groups is rather high,
  231. be sure to include the word "floppy" (or "FLOPPY") in the subject
  232. line.  If the reported problem happens when mounting floppy disks, be
  233. sure to mention also the type of the filesystem in the subject line.
  234.  
  235.  Be sure to read the FAQ before mailing/posting any bug reports!
  236.  
  237.  Alain

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