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1===================================2Linux and parallel port IDE devices3===================================4 5PARIDE v1.03 (c) 1997-8 Grant Guenther <grant@torque.net>6PATA_PARPORT (c) 2023 Ondrej Zary7 81. Introduction9===============10 11Owing to the simplicity and near universality of the parallel port interface12to personal computers, many external devices such as portable hard-disk,13CD-ROM, LS-120 and tape drives use the parallel port to connect to their14host computer. While some devices (notably scanners) use ad-hoc methods15to pass commands and data through the parallel port interface, most16external devices are actually identical to an internal model, but with17a parallel-port adapter chip added in. Some of the original parallel port18adapters were little more than mechanisms for multiplexing a SCSI bus.19(The Iomega PPA-3 adapter used in the ZIP drives is an example of this20approach). Most current designs, however, take a different approach.21The adapter chip reproduces a small ISA or IDE bus in the external device22and the communication protocol provides operations for reading and writing23device registers, as well as data block transfer functions. Sometimes,24the device being addressed via the parallel cable is a standard SCSI25controller like an NCR 5380. The "ditto" family of external tape26drives use the ISA replicator to interface a floppy disk controller,27which is then connected to a floppy-tape mechanism. The vast majority28of external parallel port devices, however, are now based on standard29IDE type devices, which require no intermediate controller. If one30were to open up a parallel port CD-ROM drive, for instance, one would31find a standard ATAPI CD-ROM drive, a power supply, and a single adapter32that interconnected a standard PC parallel port cable and a standard33IDE cable. It is usually possible to exchange the CD-ROM device with34any other device using the IDE interface.35 36The document describes the support in Linux for parallel port IDE37devices. It does not cover parallel port SCSI devices, "ditto" tape38drives or scanners. Many different devices are supported by the39parallel port IDE subsystem, including:40 41 - MicroSolutions backpack CD-ROM42 - MicroSolutions backpack PD/CD43 - MicroSolutions backpack hard-drives44 - MicroSolutions backpack 8000t tape drive45 - SyQuest EZ-135, EZ-230 & SparQ drives46 - Avatar Shark47 - Imation Superdisk LS-12048 - Maxell Superdisk LS-12049 - FreeCom Power CD50 - Hewlett-Packard 5GB and 8GB tape drives51 - Hewlett-Packard 7100 and 7200 CD-RW drives52 53as well as most of the clone and no-name products on the market.54 55To support such a wide range of devices, pata_parport is actually structured56in two parts. There is a base pata_parport module which provides an interface57to kernel libata subsystem, registry and some common methods for accessing58the parallel ports.59 60The second component is a set of low-level protocol drivers for each of the61parallel port IDE adapter chips. Thanks to the interest and encouragement of62Linux users from many parts of the world, support is available for almost all63known adapter protocols:64 65 ==== ====================================== ====66 aten ATEN EH-100 (HK)67 bpck Microsolutions backpack (US)68 comm DataStor (old-type) "commuter" adapter (TW)69 dstr DataStor EP-2000 (TW)70 epat Shuttle EPAT (UK)71 epia Shuttle EPIA (UK)72 fit2 FIT TD-2000 (US)73 fit3 FIT TD-3000 (US)74 friq Freecom IQ cable (DE)75 frpw Freecom Power (DE)76 kbic KingByte KBIC-951A and KBIC-971A (TW)77 ktti KT Technology PHd adapter (SG)78 on20 OnSpec 90c20 (US)79 on26 OnSpec 90c26 (US)80 ==== ====================================== ====81 82 832. Using pata_parport subsystem84===============================85 86While configuring the Linux kernel, you may choose either to build87the pata_parport drivers into your kernel, or to build them as modules.88 89In either case, you will need to select "Parallel port IDE device support"90and at least one of the parallel port communication protocols.91If you do not know what kind of parallel port adapter is used in your drive,92you could begin by checking the file names and any text files on your DOS93installation floppy. Alternatively, you can look at the markings on94the adapter chip itself. That's usually sufficient to identify the95correct device.96 97You can actually select all the protocol modules, and allow the pata_parport98subsystem to try them all for you.99 100For the "brand-name" products listed above, here are the protocol101and high-level drivers that you would use:102 103 ================ ============ ========104 Manufacturer Model Protocol105 ================ ============ ========106 MicroSolutions CD-ROM bpck107 MicroSolutions PD drive bpck108 MicroSolutions hard-drive bpck109 MicroSolutions 8000t tape bpck110 SyQuest EZ, SparQ epat111 Imation Superdisk epat112 Maxell Superdisk friq113 Avatar Shark epat114 FreeCom CD-ROM frpw115 Hewlett-Packard 5GB Tape epat116 Hewlett-Packard 7200e (CD) epat117 Hewlett-Packard 7200e (CD-R) epat118 ================ ============ ========119 120All parports and all protocol drivers are probed automatically unless probe=0121parameter is used. So just "modprobe epat" is enough for a Imation SuperDisk122drive to work.123 124Manual device creation::125 126 # echo "port protocol mode unit delay" >/sys/bus/pata_parport/new_device127 128where:129 130 ======== ================================================131 port parport name (or "auto" for all parports)132 protocol protocol name (or "auto" for all protocols)133 mode mode number (protocol-specific) or -1 for probe134 unit unit number (for backpack only, see below)135 delay I/O delay (see troubleshooting section below)136 ======== ================================================137 138If you happen to be using a MicroSolutions backpack device, you will139also need to know the unit ID number for each drive. This is usually140the last two digits of the drive's serial number (but read MicroSolutions'141documentation about this).142 143If you omit the parameters from the end, defaults will be used, e.g.:144 145Probe all parports with all protocols::146 147 # echo auto >/sys/bus/pata_parport/new_device148 149Probe parport0 using protocol epat and mode 4 (EPP-16)::150 151 # echo "parport0 epat 4" >/sys/bus/pata_parport/new_device152 153Probe parport0 using all protocols::154 155 # echo "parport0 auto" >/sys/bus/pata_parport/new_device156 157Probe all parports using protoocol epat::158 159 # echo "auto epat" >/sys/bus/pata_parport/new_device160 161Deleting devices::162 163 # echo pata_parport.0 >/sys/bus/pata_parport/delete_device164 165 1663. Troubleshooting167==================168 1693.1 Use EPP mode if you can170----------------------------171 172The most common problems that people report with the pata_parport drivers173concern the parallel port CMOS settings. At this time, none of the174protocol modules support ECP mode, or any ECP combination modes.175If you are able to do so, please set your parallel port into EPP mode176using your CMOS setup procedure.177 1783.2 Check the port delay179-------------------------180 181Some parallel ports cannot reliably transfer data at full speed. To182offset the errors, the protocol modules introduce a "port183delay" between each access to the i/o ports. Each protocol sets184a default value for this delay. In most cases, the user can override185the default and set it to 0 - resulting in somewhat higher transfer186rates. In some rare cases (especially with older 486 systems) the187default delays are not long enough. if you experience corrupt data188transfers, or unexpected failures, you may wish to increase the189port delay.190 1913.3 Some drives need a printer reset192-------------------------------------193 194There appear to be a number of "noname" external drives on the market195that do not always power up correctly. We have noticed this with some196drives based on OnSpec and older Freecom adapters. In these rare cases,197the adapter can often be reinitialised by issuing a "printer reset" on198the parallel port. As the reset operation is potentially disruptive in199multiple device environments, the pata_parport drivers will not do it200automatically. You can however, force a printer reset by doing::201 202 insmod lp reset=1203 rmmod lp204 205If you have one of these marginal cases, you should probably build206your pata_parport drivers as modules, and arrange to do the printer reset207before loading the pata_parport drivers.208