linux/Documentation/blockdev/paride.txt
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   2                Linux and parallel port IDE devices
   3
   4PARIDE v1.03   (c) 1997-8  Grant Guenther <grant@torque.net>
   5
   61. Introduction
   7
   8Owing to the simplicity and near universality of the parallel port interface
   9to personal computers, many external devices such as portable hard-disk,
  10CD-ROM, LS-120 and tape drives use the parallel port to connect to their
  11host computer.  While some devices (notably scanners) use ad-hoc methods
  12to pass commands and data through the parallel port interface, most 
  13external devices are actually identical to an internal model, but with
  14a parallel-port adapter chip added in.  Some of the original parallel port
  15adapters were little more than mechanisms for multiplexing a SCSI bus.
  16(The Iomega PPA-3 adapter used in the ZIP drives is an example of this
  17approach).  Most current designs, however, take a different approach.
  18The adapter chip reproduces a small ISA or IDE bus in the external device
  19and the communication protocol provides operations for reading and writing
  20device registers, as well as data block transfer functions.  Sometimes,
  21the device being addressed via the parallel cable is a standard SCSI
  22controller like an NCR 5380.  The "ditto" family of external tape
  23drives use the ISA replicator to interface a floppy disk controller,
  24which is then connected to a floppy-tape mechanism.  The vast majority
  25of external parallel port devices, however, are now based on standard
  26IDE type devices, which require no intermediate controller.  If one
  27were to open up a parallel port CD-ROM drive, for instance, one would
  28find a standard ATAPI CD-ROM drive, a power supply, and a single adapter
  29that interconnected a standard PC parallel port cable and a standard
  30IDE cable.  It is usually possible to exchange the CD-ROM device with
  31any other device using the IDE interface. 
  32
  33The document describes the support in Linux for parallel port IDE
  34devices.  It does not cover parallel port SCSI devices, "ditto" tape
  35drives or scanners.  Many different devices are supported by the 
  36parallel port IDE subsystem, including:
  37
  38        MicroSolutions backpack CD-ROM
  39        MicroSolutions backpack PD/CD
  40        MicroSolutions backpack hard-drives
  41        MicroSolutions backpack 8000t tape drive
  42        SyQuest EZ-135, EZ-230 & SparQ drives
  43        Avatar Shark
  44        Imation Superdisk LS-120
  45        Maxell Superdisk LS-120
  46        FreeCom Power CD 
  47        Hewlett-Packard 5GB and 8GB tape drives
  48        Hewlett-Packard 7100 and 7200 CD-RW drives
  49
  50as well as most of the clone and no-name products on the market.
  51
  52To support such a wide range of devices, PARIDE, the parallel port IDE
  53subsystem, is actually structured in three parts.   There is a base
  54paride module which provides a registry and some common methods for
  55accessing the parallel ports.  The second component is a set of 
  56high-level drivers for each of the different types of supported devices: 
  57
  58        pd      IDE disk
  59        pcd     ATAPI CD-ROM
  60        pf      ATAPI disk
  61        pt      ATAPI tape
  62        pg      ATAPI generic
  63
  64(Currently, the pg driver is only used with CD-R drives).
  65
  66The high-level drivers function according to the relevant standards.
  67The third component of PARIDE is a set of low-level protocol drivers
  68for each of the parallel port IDE adapter chips.  Thanks to the interest
  69and encouragement of Linux users from many parts of the world, 
  70support is available for almost all known adapter protocols:
  71
  72        aten    ATEN EH-100                            (HK)
  73        bpck    Microsolutions backpack                (US)
  74        comm    DataStor (old-type) "commuter" adapter (TW)
  75        dstr    DataStor EP-2000                       (TW)
  76        epat    Shuttle EPAT                           (UK)
  77        epia    Shuttle EPIA                           (UK)
  78        fit2    FIT TD-2000                            (US)
  79        fit3    FIT TD-3000                            (US)
  80        friq    Freecom IQ cable                       (DE)
  81        frpw    Freecom Power                          (DE)
  82        kbic    KingByte KBIC-951A and KBIC-971A       (TW)
  83        ktti    KT Technology PHd adapter              (SG)
  84        on20    OnSpec 90c20                           (US)
  85        on26    OnSpec 90c26                           (US)
  86
  87
  882. Using the PARIDE subsystem
  89
  90While configuring the Linux kernel, you may choose either to build
  91the PARIDE drivers into your kernel, or to build them as modules.
  92
  93In either case, you will need to select "Parallel port IDE device support"
  94as well as at least one of the high-level drivers and at least one
  95of the parallel port communication protocols.  If you do not know
  96what kind of parallel port adapter is used in your drive, you could
  97begin by checking the file names and any text files on your DOS 
  98installation floppy.  Alternatively, you can look at the markings on
  99the adapter chip itself.  That's usually sufficient to identify the
 100correct device.  
 101
 102You can actually select all the protocol modules, and allow the PARIDE
 103subsystem to try them all for you.
 104
 105For the "brand-name" products listed above, here are the protocol
 106and high-level drivers that you would use:
 107
 108        Manufacturer            Model           Driver  Protocol
 109        
 110        MicroSolutions          CD-ROM          pcd     bpck
 111        MicroSolutions          PD drive        pf      bpck
 112        MicroSolutions          hard-drive      pd      bpck
 113        MicroSolutions          8000t tape      pt      bpck
 114        SyQuest                 EZ, SparQ       pd      epat
 115        Imation                 Superdisk       pf      epat
 116        Maxell                  Superdisk       pf      friq
 117        Avatar                  Shark           pd      epat
 118        FreeCom                 CD-ROM          pcd     frpw
 119        Hewlett-Packard         5GB Tape        pt      epat
 120        Hewlett-Packard         7200e (CD)      pcd     epat
 121        Hewlett-Packard         7200e (CD-R)    pg      epat
 122
 1232.1  Configuring built-in drivers
 124
 125We recommend that you get to know how the drivers work and how to
 126configure them as loadable modules, before attempting to compile a
 127kernel with the drivers built-in.
 128
 129If you built all of your PARIDE support directly into your kernel,
 130and you have just a single parallel port IDE device, your kernel should
 131locate it automatically for you.  If you have more than one device,
 132you may need to give some command line options to your bootloader
 133(eg: LILO), how to do that is beyond the scope of this document.
 134
 135The high-level drivers accept a number of command line parameters, all
 136of which are documented in the source files in linux/drivers/block/paride.
 137By default, each driver will automatically try all parallel ports it
 138can find, and all protocol types that have been installed, until it finds
 139a parallel port IDE adapter.  Once it finds one, the probe stops.  So,
 140if you have more than one device, you will need to tell the drivers
 141how to identify them.  This requires specifying the port address, the
 142protocol identification number and, for some devices, the drive's
 143chain ID.  While your system is booting, a number of messages are
 144displayed on the console.  Like all such messages, they can be
 145reviewed with the 'dmesg' command.  Among those messages will be
 146some lines like:
 147
 148        paride: bpck registered as protocol 0
 149        paride: epat registered as protocol 1
 150
 151The numbers will always be the same until you build a new kernel with
 152different protocol selections.  You should note these numbers as you
 153will need them to identify the devices.
 154
 155If you happen to be using a MicroSolutions backpack device, you will
 156also need to know the unit ID number for each drive.  This is usually
 157the last two digits of the drive's serial number (but read MicroSolutions'
 158documentation about this).
 159
 160As an example, let's assume that you have a MicroSolutions PD/CD drive
 161with unit ID number 36 connected to the parallel port at 0x378, a SyQuest 
 162EZ-135 connected to the chained port on the PD/CD drive and also an 
 163Imation Superdisk connected to port 0x278.  You could give the following 
 164options on your boot command:
 165
 166        pd.drive0=0x378,1 pf.drive0=0x278,1 pf.drive1=0x378,0,36
 167
 168In the last option, pf.drive1 configures device /dev/pf1, the 0x378
 169is the parallel port base address, the 0 is the protocol registration
 170number and 36 is the chain ID.
 171
 172Please note:  while PARIDE will work both with and without the 
 173PARPORT parallel port sharing system that is included by the
 174"Parallel port support" option, PARPORT must be included and enabled
 175if you want to use chains of devices on the same parallel port.
 176
 1772.2  Loading and configuring PARIDE as modules
 178
 179It is much faster and simpler to get to understand the PARIDE drivers
 180if you use them as loadable kernel modules.   
 181
 182Note 1:  using these drivers with the "kerneld" automatic module loading
 183system is not recommended for beginners, and is not documented here.  
 184
 185Note 2:  if you build PARPORT support as a loadable module, PARIDE must
 186also be built as loadable modules, and PARPORT must be loaded before the
 187PARIDE modules.
 188
 189To use PARIDE, you must begin by 
 190
 191        insmod paride
 192
 193this loads a base module which provides a registry for the protocols,
 194among other tasks.
 195
 196Then, load as many of the protocol modules as you think you might need.
 197As you load each module, it will register the protocols that it supports,
 198and print a log message to your kernel log file and your console. For 
 199example:
 200
 201        # insmod epat
 202        paride: epat registered as protocol 0
 203        # insmod kbic
 204        paride: k951 registered as protocol 1
 205        paride: k971 registered as protocol 2
 206
 207Finally, you can load high-level drivers for each kind of device that
 208you have connected.  By default, each driver will autoprobe for a single 
 209device, but you can support up to four similar devices by giving their
 210individual co-ordinates when you load the driver.
 211
 212For example, if you had two no-name CD-ROM drives both using the
 213KingByte KBIC-951A adapter, one on port 0x378 and the other on 0x3bc
 214you could give the following command:
 215
 216        # insmod pcd drive0=0x378,1 drive1=0x3bc,1
 217
 218For most adapters, giving a port address and protocol number is sufficient,
 219but check the source files in linux/drivers/block/paride for more 
 220information.  (Hopefully someone will write some man pages one day !).
 221
 222As another example, here's what happens when PARPORT is installed, and
 223a SyQuest EZ-135 is attached to port 0x378:
 224
 225        # insmod paride
 226        paride: version 1.0 installed
 227        # insmod epat
 228        paride: epat registered as protocol 0
 229        # insmod pd
 230        pd: pd version 1.0, major 45, cluster 64, nice 0
 231        pda: Sharing parport1 at 0x378
 232        pda: epat 1.0, Shuttle EPAT chip c3 at 0x378, mode 5 (EPP-32), delay 1
 233        pda: SyQuest EZ135A, 262144 blocks [128M], (512/16/32), removable media
 234         pda: pda1
 235
 236Note that the last line is the output from the generic partition table
 237scanner - in this case it reports that it has found a disk with one partition.
 238
 2392.3  Using a PARIDE device
 240
 241Once the drivers have been loaded, you can access PARIDE devices in the
 242same way as their traditional counterparts.  You will probably need to
 243create the device "special files".  Here is a simple script that you can
 244cut to a file and execute:
 245
 246#!/bin/bash
 247#
 248# mkd -- a script to create the device special files for the PARIDE subsystem
 249#
 250function mkdev {
 251  mknod $1 $2 $3 $4 ; chmod 0660 $1 ; chown root:disk $1
 252}
 253#
 254function pd {
 255  D=$( printf \\$( printf "x%03x" $[ $1 + 97 ] ) )
 256  mkdev pd$D b 45 $[ $1 * 16 ]
 257  for P in 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15
 258  do mkdev pd$D$P b 45 $[ $1 * 16 + $P ]
 259  done
 260}
 261#
 262cd /dev
 263#
 264for u in 0 1 2 3 ; do pd $u ; done
 265for u in 0 1 2 3 ; do mkdev pcd$u b 46 $u ; done 
 266for u in 0 1 2 3 ; do mkdev pf$u  b 47 $u ; done 
 267for u in 0 1 2 3 ; do mkdev pt$u  c 96 $u ; done 
 268for u in 0 1 2 3 ; do mkdev npt$u c 96 $[ $u + 128 ] ; done 
 269for u in 0 1 2 3 ; do mkdev pg$u  c 97 $u ; done 
 270#
 271# end of mkd
 272
 273With the device files and drivers in place, you can access PARIDE devices
 274like any other Linux device.   For example, to mount a CD-ROM in pcd0, use:
 275
 276        mount /dev/pcd0 /cdrom
 277
 278If you have a fresh Avatar Shark cartridge, and the drive is pda, you
 279might do something like:
 280
 281        fdisk /dev/pda          -- make a new partition table with
 282                                   partition 1 of type 83
 283
 284        mke2fs /dev/pda1        -- to build the file system
 285
 286        mkdir /shark            -- make a place to mount the disk
 287
 288        mount /dev/pda1 /shark
 289
 290Devices like the Imation superdisk work in the same way, except that
 291they do not have a partition table.  For example to make a 120MB
 292floppy that you could share with a DOS system:
 293
 294        mkdosfs /dev/pf0
 295        mount /dev/pf0 /mnt
 296
 297
 2982.4  The pf driver
 299
 300The pf driver is intended for use with parallel port ATAPI disk
 301devices.  The most common devices in this category are PD drives
 302and LS-120 drives.  Traditionally, media for these devices are not
 303partitioned.  Consequently, the pf driver does not support partitioned
 304media.  This may be changed in a future version of the driver. 
 305
 3062.5  Using the pt driver
 307
 308The pt driver for parallel port ATAPI tape drives is a minimal driver.
 309It does not yet support many of the standard tape ioctl operations. 
 310For best performance, a block size of 32KB should be used.  You will
 311probably want to set the parallel port delay to 0, if you can.
 312
 3132.6  Using the pg driver
 314
 315The pg driver can be used in conjunction with the cdrecord program
 316to create CD-ROMs.  Please get cdrecord version 1.6.1 or later
 317from ftp://ftp.fokus.gmd.de/pub/unix/cdrecord/ .  To record CD-R media 
 318your parallel port should ideally be set to EPP mode, and the "port delay" 
 319should be set to 0.  With those settings it is possible to record at 2x 
 320speed without any buffer underruns.  If you cannot get the driver to work
 321in EPP mode, try to use "bidirectional" or "PS/2" mode and 1x speeds only.
 322
 323
 3243. Troubleshooting
 325
 3263.1  Use EPP mode if you can
 327
 328The most common problems that people report with the PARIDE drivers
 329concern the parallel port CMOS settings.  At this time, none of the
 330PARIDE protocol modules support ECP mode, or any ECP combination modes.
 331If you are able to do so, please set your parallel port into EPP mode
 332using your CMOS setup procedure.
 333
 3343.2  Check the port delay
 335
 336Some parallel ports cannot reliably transfer data at full speed.  To
 337offset the errors, the PARIDE protocol modules introduce a "port
 338delay" between each access to the i/o ports.  Each protocol sets
 339a default value for this delay.  In most cases, the user can override
 340the default and set it to 0 - resulting in somewhat higher transfer
 341rates.  In some rare cases (especially with older 486 systems) the
 342default delays are not long enough.  if you experience corrupt data
 343transfers, or unexpected failures, you may wish to increase the
 344port delay.   The delay can be programmed using the "driveN" parameters
 345to each of the high-level drivers.  Please see the notes above, or
 346read the comments at the beginning of the driver source files in
 347linux/drivers/block/paride.
 348
 3493.3  Some drives need a printer reset
 350
 351There appear to be a number of "noname" external drives on the market
 352that do not always power up correctly.  We have noticed this with some
 353drives based on OnSpec and older Freecom adapters.  In these rare cases,
 354the adapter can often be reinitialised by issuing a "printer reset" on
 355the parallel port.  As the reset operation is potentially disruptive in 
 356multiple device environments, the PARIDE drivers will not do it 
 357automatically.  You can however, force a printer reset by doing:
 358
 359        insmod lp reset=1
 360        rmmod lp
 361
 362If you have one of these marginal cases, you should probably build
 363your paride drivers as modules, and arrange to do the printer reset
 364before loading the PARIDE drivers. 
 365
 3663.4  Use the verbose option and dmesg if you need help
 367
 368While a lot of testing has gone into these drivers to make them work
 369as smoothly as possible, problems will arise.  If you do have problems,
 370please check all the obvious things first:  does the drive work in
 371DOS with the manufacturer's drivers ?  If that doesn't yield any useful
 372clues, then please make sure that only one drive is hooked to your system,
 373and that either (a) PARPORT is enabled or (b) no other device driver
 374is using your parallel port (check in /proc/ioports).  Then, load the
 375appropriate drivers (you can load several protocol modules if you want)
 376as in:
 377
 378        # insmod paride
 379        # insmod epat
 380        # insmod bpck
 381        # insmod kbic
 382        ...
 383        # insmod pd verbose=1
 384
 385(using the correct driver for the type of device you have, of course).
 386The verbose=1 parameter will cause the drivers to log a trace of their
 387activity as they attempt to locate your drive.
 388
 389Use 'dmesg' to capture a log of all the PARIDE messages (any messages
 390beginning with paride:, a protocol module's name or a driver's name) and
 391include that with your bug report.  You can submit a bug report in one
 392of two ways.  Either send it directly to the author of the PARIDE suite,
 393by e-mail to grant@torque.net, or join the linux-parport mailing list
 394and post your report there.
 395
 3963.5  For more information or help
 397
 398You can join the linux-parport mailing list by sending a mail message
 399to 
 400                linux-parport-request@torque.net
 401
 402with the single word 
 403
 404                subscribe
 405
 406in the body of the mail message (not in the subject line).   Please be
 407sure that your mail program is correctly set up when you do this,  as
 408the list manager is a robot that will subscribe you using the reply
 409address in your mail headers.  REMOVE any anti-spam gimmicks you may
 410have in your mail headers, when sending mail to the list server.
 411
 412You might also find some useful information on the linux-parport
 413web pages (although they are not always up to date) at
 414
 415        http://web.archive.org/web/*/http://www.torque.net/parport/
 416
 417
 418
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