0001 =============
0002 Floppy Driver
0003 =============
0004
0005 FAQ list:
0006 =========
0007
0008 A FAQ list may be found in the fdutils package (see below), and also
0009 at <https://fdutils.linux.lu/faq.html>.
0010
0011
0012 LILO configuration options (Thinkpad users, read this)
0013 ======================================================
0014
0015 The floppy driver is configured using the 'floppy=' option in
0016 lilo. This option can be typed at the boot prompt, or entered in the
0017 lilo configuration file.
0018
0019 Example: If your kernel is called linux-2.6.9, type the following line
0020 at the lilo boot prompt (if you have a thinkpad)::
0021
0022 linux-2.6.9 floppy=thinkpad
0023
0024 You may also enter the following line in /etc/lilo.conf, in the description
0025 of linux-2.6.9::
0026
0027 append = "floppy=thinkpad"
0028
0029 Several floppy related options may be given, example::
0030
0031 linux-2.6.9 floppy=daring floppy=two_fdc
0032 append = "floppy=daring floppy=two_fdc"
0033
0034 If you give options both in the lilo config file and on the boot
0035 prompt, the option strings of both places are concatenated, the boot
0036 prompt options coming last. That's why there are also options to
0037 restore the default behavior.
0038
0039
0040 Module configuration options
0041 ============================
0042
0043 If you use the floppy driver as a module, use the following syntax::
0044
0045 modprobe floppy floppy="<options>"
0046
0047 Example::
0048
0049 modprobe floppy floppy="omnibook messages"
0050
0051 If you need certain options enabled every time you load the floppy driver,
0052 you can put::
0053
0054 options floppy floppy="omnibook messages"
0055
0056 in a configuration file in /etc/modprobe.d/.
0057
0058
0059 The floppy driver related options are:
0060
0061 floppy=asus_pci
0062 Sets the bit mask to allow only units 0 and 1. (default)
0063
0064 floppy=daring
0065 Tells the floppy driver that you have a well behaved floppy controller.
0066 This allows more efficient and smoother operation, but may fail on
0067 certain controllers. This may speed up certain operations.
0068
0069 floppy=0,daring
0070 Tells the floppy driver that your floppy controller should be used
0071 with caution.
0072
0073 floppy=one_fdc
0074 Tells the floppy driver that you have only one floppy controller.
0075 (default)
0076
0077 floppy=two_fdc / floppy=<address>,two_fdc
0078 Tells the floppy driver that you have two floppy controllers.
0079 The second floppy controller is assumed to be at <address>.
0080 This option is not needed if the second controller is at address
0081 0x370, and if you use the 'cmos' option.
0082
0083 floppy=thinkpad
0084 Tells the floppy driver that you have a Thinkpad. Thinkpads use an
0085 inverted convention for the disk change line.
0086
0087 floppy=0,thinkpad
0088 Tells the floppy driver that you don't have a Thinkpad.
0089
0090 floppy=omnibook / floppy=nodma
0091 Tells the floppy driver not to use Dma for data transfers.
0092 This is needed on HP Omnibooks, which don't have a workable
0093 DMA channel for the floppy driver. This option is also useful
0094 if you frequently get "Unable to allocate DMA memory" messages.
0095 Indeed, dma memory needs to be continuous in physical memory,
0096 and is thus harder to find, whereas non-dma buffers may be
0097 allocated in virtual memory. However, I advise against this if
0098 you have an FDC without a FIFO (8272A or 82072). 82072A and
0099 later are OK. You also need at least a 486 to use nodma.
0100 If you use nodma mode, I suggest you also set the FIFO
0101 threshold to 10 or lower, in order to limit the number of data
0102 transfer interrupts.
0103
0104 If you have a FIFO-able FDC, the floppy driver automatically
0105 falls back on non DMA mode if no DMA-able memory can be found.
0106 If you want to avoid this, explicitly ask for 'yesdma'.
0107
0108 floppy=yesdma
0109 Tells the floppy driver that a workable DMA channel is available.
0110 (default)
0111
0112 floppy=nofifo
0113 Disables the FIFO entirely. This is needed if you get "Bus
0114 master arbitration error" messages from your Ethernet card (or
0115 from other devices) while accessing the floppy.
0116
0117 floppy=usefifo
0118 Enables the FIFO. (default)
0119
0120 floppy=<threshold>,fifo_depth
0121 Sets the FIFO threshold. This is mostly relevant in DMA
0122 mode. If this is higher, the floppy driver tolerates more
0123 interrupt latency, but it triggers more interrupts (i.e. it
0124 imposes more load on the rest of the system). If this is
0125 lower, the interrupt latency should be lower too (faster
0126 processor). The benefit of a lower threshold is less
0127 interrupts.
0128
0129 To tune the fifo threshold, switch on over/underrun messages
0130 using 'floppycontrol --messages'. Then access a floppy
0131 disk. If you get a huge amount of "Over/Underrun - retrying"
0132 messages, then the fifo threshold is too low. Try with a
0133 higher value, until you only get an occasional Over/Underrun.
0134 It is a good idea to compile the floppy driver as a module
0135 when doing this tuning. Indeed, it allows to try different
0136 fifo values without rebooting the machine for each test. Note
0137 that you need to do 'floppycontrol --messages' every time you
0138 re-insert the module.
0139
0140 Usually, tuning the fifo threshold should not be needed, as
0141 the default (0xa) is reasonable.
0142
0143 floppy=<drive>,<type>,cmos
0144 Sets the CMOS type of <drive> to <type>. This is mandatory if
0145 you have more than two floppy drives (only two can be
0146 described in the physical CMOS), or if your BIOS uses
0147 non-standard CMOS types. The CMOS types are:
0148
0149 == ==================================
0150 0 Use the value of the physical CMOS
0151 1 5 1/4 DD
0152 2 5 1/4 HD
0153 3 3 1/2 DD
0154 4 3 1/2 HD
0155 5 3 1/2 ED
0156 6 3 1/2 ED
0157 16 unknown or not installed
0158 == ==================================
0159
0160 (Note: there are two valid types for ED drives. This is because 5 was
0161 initially chosen to represent floppy *tapes*, and 6 for ED drives.
0162 AMI ignored this, and used 5 for ED drives. That's why the floppy
0163 driver handles both.)
0164
0165 floppy=unexpected_interrupts
0166 Print a warning message when an unexpected interrupt is received.
0167 (default)
0168
0169 floppy=no_unexpected_interrupts / floppy=L40SX
0170 Don't print a message when an unexpected interrupt is received. This
0171 is needed on IBM L40SX laptops in certain video modes. (There seems
0172 to be an interaction between video and floppy. The unexpected
0173 interrupts affect only performance, and can be safely ignored.)
0174
0175 floppy=broken_dcl
0176 Don't use the disk change line, but assume that the disk was
0177 changed whenever the device node is reopened. Needed on some
0178 boxes where the disk change line is broken or unsupported.
0179 This should be regarded as a stopgap measure, indeed it makes
0180 floppy operation less efficient due to unneeded cache
0181 flushings, and slightly more unreliable. Please verify your
0182 cable, connection and jumper settings if you have any DCL
0183 problems. However, some older drives, and also some laptops
0184 are known not to have a DCL.
0185
0186 floppy=debug
0187 Print debugging messages.
0188
0189 floppy=messages
0190 Print informational messages for some operations (disk change
0191 notifications, warnings about over and underruns, and about
0192 autodetection).
0193
0194 floppy=silent_dcl_clear
0195 Uses a less noisy way to clear the disk change line (which
0196 doesn't involve seeks). Implied by 'daring' option.
0197
0198 floppy=<nr>,irq
0199 Sets the floppy IRQ to <nr> instead of 6.
0200
0201 floppy=<nr>,dma
0202 Sets the floppy DMA channel to <nr> instead of 2.
0203
0204 floppy=slow
0205 Use PS/2 stepping rate::
0206
0207 PS/2 floppies have much slower step rates than regular floppies.
0208 It's been recommended that take about 1/4 of the default speed
0209 in some more extreme cases.
0210
0211
0212 Supporting utilities and additional documentation:
0213 ==================================================
0214
0215 Additional parameters of the floppy driver can be configured at
0216 runtime. Utilities which do this can be found in the fdutils package.
0217 This package also contains a new version of mtools which allows to
0218 access high capacity disks (up to 1992K on a high density 3 1/2 disk!).
0219 It also contains additional documentation about the floppy driver.
0220
0221 The latest version can be found at fdutils homepage:
0222
0223 https://fdutils.linux.lu
0224
0225 The fdutils releases can be found at:
0226
0227 https://fdutils.linux.lu/download.html
0228
0229 http://www.tux.org/pub/knaff/fdutils/
0230
0231 ftp://metalab.unc.edu/pub/Linux/utils/disk-management/
0232
0233 Reporting problems about the floppy driver
0234 ==========================================
0235
0236 If you have a question or a bug report about the floppy driver, mail
0237 me at Alain.Knaff@poboxes.com . If you post to Usenet, preferably use
0238 comp.os.linux.hardware. As the volume in these groups is rather high,
0239 be sure to include the word "floppy" (or "FLOPPY") in the subject
0240 line. If the reported problem happens when mounting floppy disks, be
0241 sure to mention also the type of the filesystem in the subject line.
0242
0243 Be sure to read the FAQ before mailing/posting any bug reports!
0244
0245 Alain
0246
0247 Changelog
0248 =========
0249
0250 10-30-2004 :
0251 Cleanup, updating, add reference to module configuration.
0252 James Nelson <james4765@gmail.com>
0253
0254 6-3-2000 :
0255 Original Document
