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+
+                Linux and parallel port IDE devices
+
+PARIDE v1.03   (c) 1997-8  Grant Guenther <grant@torque.net>
+
+1. Introduction
+
+Owing to the simplicity and near universality of the parallel port interface
+to personal computers, many external devices such as portable hard-disk,
+CD-ROM, LS-120 and tape drives use the parallel port to connect to their
+host computer.  While some devices (notably scanners) use ad-hoc methods
+to pass commands and data through the parallel port interface, most 
+external devices are actually identical to an internal model, but with
+a parallel-port adapter chip added in.  Some of the original parallel port
+adapters were little more than mechanisms for multiplexing a SCSI bus.
+(The Iomega PPA-3 adapter used in the ZIP drives is an example of this
+approach).  Most current designs, however, take a different approach.
+The adapter chip reproduces a small ISA or IDE bus in the external device
+and the communication protocol provides operations for reading and writing
+device registers, as well as data block transfer functions.  Sometimes,
+the device being addressed via the parallel cable is a standard SCSI
+controller like an NCR 5380.  The "ditto" family of external tape
+drives use the ISA replicator to interface a floppy disk controller,
+which is then connected to a floppy-tape mechanism.  The vast majority
+of external parallel port devices, however, are now based on standard
+IDE type devices, which require no intermediate controller.  If one
+were to open up a parallel port CD-ROM drive, for instance, one would
+find a standard ATAPI CD-ROM drive, a power supply, and a single adapter
+that interconnected a standard PC parallel port cable and a standard
+IDE cable.  It is usually possible to exchange the CD-ROM device with
+any other device using the IDE interface. 
+
+The document describes the support in Linux for parallel port IDE
+devices.  It does not cover parallel port SCSI devices, "ditto" tape
+drives or scanners.  Many different devices are supported by the 
+parallel port IDE subsystem, including:
+
+        MicroSolutions backpack CD-ROM
+        MicroSolutions backpack PD/CD
+        MicroSolutions backpack hard-drives
+        MicroSolutions backpack 8000t tape drive
+        SyQuest EZ-135, EZ-230 & SparQ drives
+        Avatar Shark
+        Imation Superdisk LS-120
+        Maxell Superdisk LS-120
+        FreeCom Power CD 
+        Hewlett-Packard 5GB and 8GB tape drives
+        Hewlett-Packard 7100 and 7200 CD-RW drives
+
+as well as most of the clone and no-name products on the market.
+
+To support such a wide range of devices, PARIDE, the parallel port IDE
+subsystem, is actually structured in three parts.   There is a base
+paride module which provides a registry and some common methods for
+accessing the parallel ports.  The second component is a set of 
+high-level drivers for each of the different types of supported devices: 
+
+        pd      IDE disk
+        pcd     ATAPI CD-ROM
+        pf      ATAPI disk
+        pt      ATAPI tape
+        pg      ATAPI generic
+
+(Currently, the pg driver is only used with CD-R drives).
+
+The high-level drivers function according to the relevant standards.
+The third component of PARIDE is a set of low-level protocol drivers
+for each of the parallel port IDE adapter chips.  Thanks to the interest
+and encouragement of Linux users from many parts of the world, 
+support is available for almost all known adapter protocols:
+
+        aten    ATEN EH-100                            (HK)
+        bpck    Microsolutions backpack                (US)
+        comm    DataStor (old-type) "commuter" adapter (TW)
+        dstr    DataStor EP-2000                       (TW)
+        epat    Shuttle EPAT                           (UK)
+        epia    Shuttle EPIA                           (UK)
+        fit2    FIT TD-2000                            (US)
+        fit3    FIT TD-3000                            (US)
+        friq    Freecom IQ cable                       (DE)
+        frpw    Freecom Power                          (DE)
+        kbic    KingByte KBIC-951A and KBIC-971A       (TW)
+        ktti    KT Technology PHd adapter              (SG)
+        on20    OnSpec 90c20                           (US)
+        on26    OnSpec 90c26                           (US)
+
+
+2. Using the PARIDE subsystem
+
+While configuring the Linux kernel, you may choose either to build
+the PARIDE drivers into your kernel, or to build them as modules.
+
+In either case, you will need to select "Parallel port IDE device support"
+as well as at least one of the high-level drivers and at least one
+of the parallel port communication protocols.  If you do not know
+what kind of parallel port adapter is used in your drive, you could
+begin by checking the file names and any text files on your DOS 
+installation floppy.  Alternatively, you can look at the markings on
+the adapter chip itself.  That's usually sufficient to identify the
+correct device.  
+
+You can actually select all the protocol modules, and allow the PARIDE
+subsystem to try them all for you.
+
+For the "brand-name" products listed above, here are the protocol
+and high-level drivers that you would use:
+
+        Manufacturer            Model           Driver  Protocol
+        
+        MicroSolutions          CD-ROM          pcd     bpck
+        MicroSolutions          PD drive        pf      bpck
+        MicroSolutions          hard-drive      pd      bpck
+        MicroSolutions          8000t tape      pt      bpck
+        SyQuest                 EZ, SparQ       pd      epat
+        Imation                 Superdisk       pf      epat
+        Maxell                  Superdisk       pf      friq
+        Avatar                  Shark           pd      epat
+        FreeCom                 CD-ROM          pcd     frpw
+        Hewlett-Packard         5GB Tape        pt      epat
+        Hewlett-Packard         7200e (CD)      pcd     epat
+        Hewlett-Packard         7200e (CD-R)    pg      epat
+
+2.1  Configuring built-in drivers
+
+We recommend that you get to know how the drivers work and how to
+configure them as loadable modules, before attempting to compile a
+kernel with the drivers built-in.
+
+If you built all of your PARIDE support directly into your kernel,
+and you have just a single parallel port IDE device, your kernel should
+locate it automatically for you.  If you have more than one device,
+you may need to give some command line options to your bootloader
+(eg: LILO), how to do that is beyond the scope of this document.
+
+The high-level drivers accept a number of command line parameters, all
+of which are documented in the source files in linux/drivers/block/paride.
+By default, each driver will automatically try all parallel ports it
+can find, and all protocol types that have been installed, until it finds
+a parallel port IDE adapter.  Once it finds one, the probe stops.  So,
+if you have more than one device, you will need to tell the drivers
+how to identify them.  This requires specifying the port address, the
+protocol identification number and, for some devices, the drive's
+chain ID.  While your system is booting, a number of messages are
+displayed on the console.  Like all such messages, they can be
+reviewed with the 'dmesg' command.  Among those messages will be
+some lines like:
+
+        paride: bpck registered as protocol 0
+        paride: epat registered as protocol 1
+
+The numbers will always be the same until you build a new kernel with
+different protocol selections.  You should note these numbers as you
+will need them to identify the devices.
+
+If you happen to be using a MicroSolutions backpack device, you will
+also need to know the unit ID number for each drive.  This is usually
+the last two digits of the drive's serial number (but read MicroSolutions'
+documentation about this).
+
+As an example, let's assume that you have a MicroSolutions PD/CD drive
+with unit ID number 36 connected to the parallel port at 0x378, a SyQuest 
+EZ-135 connected to the chained port on the PD/CD drive and also an 
+Imation Superdisk connected to port 0x278.  You could give the following 
+options on your boot command:
+
+        pd.drive0=0x378,1 pf.drive0=0x278,1 pf.drive1=0x378,0,36
+
+In the last option, pf.drive1 configures device /dev/pf1, the 0x378
+is the parallel port base address, the 0 is the protocol registration
+number and 36 is the chain ID.
+
+Please note:  while PARIDE will work both with and without the 
+PARPORT parallel port sharing system that is included by the
+"Parallel port support" option, PARPORT must be included and enabled
+if you want to use chains of devices on the same parallel port.
+
+2.2  Loading and configuring PARIDE as modules
+
+It is much faster and simpler to get to understand the PARIDE drivers
+if you use them as loadable kernel modules.   
+
+Note 1:  using these drivers with the "kerneld" automatic module loading
+system is not recommended for beginners, and is not documented here.  
+
+Note 2:  if you build PARPORT support as a loadable module, PARIDE must
+also be built as loadable modules, and PARPORT must be loaded before the
+PARIDE modules.
+
+To use PARIDE, you must begin by 
+
+        insmod paride
+
+this loads a base module which provides a registry for the protocols,
+among other tasks.
+
+Then, load as many of the protocol modules as you think you might need.
+As you load each module, it will register the protocols that it supports,
+and print a log message to your kernel log file and your console. For 
+example:
+
+        # insmod epat
+        paride: epat registered as protocol 0
+        # insmod kbic
+        paride: k951 registered as protocol 1
+        paride: k971 registered as protocol 2
+
+Finally, you can load high-level drivers for each kind of device that
+you have connected.  By default, each driver will autoprobe for a single 
+device, but you can support up to four similar devices by giving their
+individual co-ordinates when you load the driver.
+
+For example, if you had two no-name CD-ROM drives both using the
+KingByte KBIC-951A adapter, one on port 0x378 and the other on 0x3bc
+you could give the following command:
+
+        # insmod pcd drive0=0x378,1 drive1=0x3bc,1
+
+For most adapters, giving a port address and protocol number is sufficient,
+but check the source files in linux/drivers/block/paride for more 
+information.  (Hopefully someone will write some man pages one day !).
+
+As another example, here's what happens when PARPORT is installed, and
+a SyQuest EZ-135 is attached to port 0x378:
+
+        # insmod paride
+        paride: version 1.0 installed
+        # insmod epat
+        paride: epat registered as protocol 0
+        # insmod pd
+        pd: pd version 1.0, major 45, cluster 64, nice 0
+        pda: Sharing parport1 at 0x378
+        pda: epat 1.0, Shuttle EPAT chip c3 at 0x378, mode 5 (EPP-32), delay 1
+        pda: SyQuest EZ135A, 262144 blocks [128M], (512/16/32), removable media
+         pda: pda1
+
+Note that the last line is the output from the generic partition table
+scanner - in this case it reports that it has found a disk with one partition.
+
+2.3  Using a PARIDE device
+
+Once the drivers have been loaded, you can access PARIDE devices in the
+same way as their traditional counterparts.  You will probably need to
+create the device "special files".  Here is a simple script that you can
+cut to a file and execute:
+
+#!/bin/bash
+#
+# mkd -- a script to create the device special files for the PARIDE subsystem
+#
+function mkdev {
+  mknod $1 $2 $3 $4 ; chmod 0660 $1 ; chown root:disk $1
+}
+#
+function pd {
+  D=$( printf \\$( printf "x%03x" $[ $1 + 97 ] ) )
+  mkdev pd$D b 45 $[ $1 * 16 ]
+  for P in 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15
+  do mkdev pd$D$P b 45 $[ $1 * 16 + $P ]
+  done
+}
+#
+cd /dev
+#
+for u in 0 1 2 3 ; do pd $u ; done
+for u in 0 1 2 3 ; do mkdev pcd$u b 46 $u ; done 
+for u in 0 1 2 3 ; do mkdev pf$u  b 47 $u ; done 
+for u in 0 1 2 3 ; do mkdev pt$u  c 96 $u ; done 
+for u in 0 1 2 3 ; do mkdev npt$u c 96 $[ $u + 128 ] ; done 
+for u in 0 1 2 3 ; do mkdev pg$u  c 97 $u ; done 
+#
+# end of mkd
+
+With the device files and drivers in place, you can access PARIDE devices
+like any other Linux device.   For example, to mount a CD-ROM in pcd0, use:
+
+        mount /dev/pcd0 /cdrom
+
+If you have a fresh Avatar Shark cartridge, and the drive is pda, you
+might do something like:
+
+        fdisk /dev/pda          -- make a new partition table with
+                                   partition 1 of type 83
+
+        mke2fs /dev/pda1        -- to build the file system
+
+        mkdir /shark            -- make a place to mount the disk
+
+        mount /dev/pda1 /shark
+
+Devices like the Imation superdisk work in the same way, except that
+they do not have a partition table.  For example to make a 120MB
+floppy that you could share with a DOS system:
+
+        mkdosfs /dev/pf0
+        mount /dev/pf0 /mnt
+
+
+2.4  The pf driver
+
+The pf driver is intended for use with parallel port ATAPI disk
+devices.  The most common devices in this category are PD drives
+and LS-120 drives.  Traditionally, media for these devices are not
+partitioned.  Consequently, the pf driver does not support partitioned
+media.  This may be changed in a future version of the driver. 
+
+2.5  Using the pt driver
+
+The pt driver for parallel port ATAPI tape drives is a minimal driver.
+It does not yet support many of the standard tape ioctl operations. 
+For best performance, a block size of 32KB should be used.  You will
+probably want to set the parallel port delay to 0, if you can.
+
+2.6  Using the pg driver
+
+The pg driver can be used in conjunction with the cdrecord program
+to create CD-ROMs.  Please get cdrecord version 1.6.1 or later
+from ftp://ftp.fokus.gmd.de/pub/unix/cdrecord/ .  To record CD-R media 
+your parallel port should ideally be set to EPP mode, and the "port delay" 
+should be set to 0.  With those settings it is possible to record at 2x 
+speed without any buffer underruns.  If you cannot get the driver to work
+in EPP mode, try to use "bidirectional" or "PS/2" mode and 1x speeds only.
+
+
+3. Troubleshooting
+
+3.1  Use EPP mode if you can
+
+The most common problems that people report with the PARIDE drivers
+concern the parallel port CMOS settings.  At this time, none of the
+PARIDE protocol modules support ECP mode, or any ECP combination modes.
+If you are able to do so, please set your parallel port into EPP mode
+using your CMOS setup procedure.
+
+3.2  Check the port delay
+
+Some parallel ports cannot reliably transfer data at full speed.  To
+offset the errors, the PARIDE protocol modules introduce a "port
+delay" between each access to the i/o ports.  Each protocol sets
+a default value for this delay.  In most cases, the user can override
+the default and set it to 0 - resulting in somewhat higher transfer
+rates.  In some rare cases (especially with older 486 systems) the
+default delays are not long enough.  if you experience corrupt data
+transfers, or unexpected failures, you may wish to increase the
+port delay.   The delay can be programmed using the "driveN" parameters
+to each of the high-level drivers.  Please see the notes above, or
+read the comments at the beginning of the driver source files in
+linux/drivers/block/paride.
+
+3.3  Some drives need a printer reset
+
+There appear to be a number of "noname" external drives on the market
+that do not always power up correctly.  We have noticed this with some
+drives based on OnSpec and older Freecom adapters.  In these rare cases,
+the adapter can often be reinitialised by issuing a "printer reset" on
+the parallel port.  As the reset operation is potentially disruptive in 
+multiple device environments, the PARIDE drivers will not do it 
+automatically.  You can however, force a printer reset by doing:
+
+        insmod lp reset=1
+        rmmod lp
+
+If you have one of these marginal cases, you should probably build
+your paride drivers as modules, and arrange to do the printer reset
+before loading the PARIDE drivers. 
+
+3.4  Use the verbose option and dmesg if you need help
+
+While a lot of testing has gone into these drivers to make them work
+as smoothly as possible, problems will arise.  If you do have problems,
+please check all the obvious things first:  does the drive work in
+DOS with the manufacturer's drivers ?  If that doesn't yield any useful
+clues, then please make sure that only one drive is hooked to your system,
+and that either (a) PARPORT is enabled or (b) no other device driver
+is using your parallel port (check in /proc/ioports).  Then, load the
+appropriate drivers (you can load several protocol modules if you want)
+as in:
+
+        # insmod paride
+        # insmod epat
+        # insmod bpck
+        # insmod kbic
+        ...
+        # insmod pd verbose=1
+
+(using the correct driver for the type of device you have, of course).
+The verbose=1 parameter will cause the drivers to log a trace of their
+activity as they attempt to locate your drive.
+
+Use 'dmesg' to capture a log of all the PARIDE messages (any messages
+beginning with paride:, a protocol module's name or a driver's name) and
+include that with your bug report.  You can submit a bug report in one
+of two ways.  Either send it directly to the author of the PARIDE suite,
+by e-mail to grant@torque.net, or join the linux-parport mailing list
+and post your report there.
+
+3.5  For more information or help
+
+You can join the linux-parport mailing list by sending a mail message
+to 
+                linux-parport-request@torque.net
+
+with the single word 
+
+                subscribe
+
+in the body of the mail message (not in the subject line).   Please be
+sure that your mail program is correctly set up when you do this,  as
+the list manager is a robot that will subscribe you using the reply
+address in your mail headers.  REMOVE any anti-spam gimmicks you may
+have in your mail headers, when sending mail to the list server.
+
+You might also find some useful information on the linux-parport
+web pages (although they are not always up to date) at
+
+        http://www.torque.net/parport/
+
+