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authorLinus Torvalds <>2005-04-16 15:20:36 -0700
committerLinus Torvalds <>2005-04-16 15:20:36 -0700
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tree0bba044c4ce775e45a88a51686b5d9f90697ea9d /Documentation/paride.txt
Initial git repository build. I'm not bothering with the full history, even though we have it. We can create a separate "historical" git archive of that later if we want to, and in the meantime it's about 3.2GB when imported into git - space that would just make the early git days unnecessarily complicated, when we don't have a lot of good infrastructure for it. Let it rip!
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+ Linux and parallel port IDE devices
+PARIDE v1.03 (c) 1997-8 Grant Guenther <>
+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
+ 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
+ # 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:
+# 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 . 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
+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, 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
+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