1=================================== 2Linux and parallel port IDE devices 3=================================== 4 5PARIDE v1.03 (c) 1997-8 Grant Guenther <grant@torque.net> 6PATA_PARPORT (c) 2023 Ondrej Zary 7 81. Introduction 9=============== 10 11Owing to the simplicity and near universality of the parallel port interface 12to personal computers, many external devices such as portable hard-disk, 13CD-ROM, LS-120 and tape drives use the parallel port to connect to their 14host computer. While some devices (notably scanners) use ad-hoc methods 15to pass commands and data through the parallel port interface, most 16external devices are actually identical to an internal model, but with 17a parallel-port adapter chip added in. Some of the original parallel port 18adapters 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 this 20approach). Most current designs, however, take a different approach. 21The adapter chip reproduces a small ISA or IDE bus in the external device 22and the communication protocol provides operations for reading and writing 23device registers, as well as data block transfer functions. Sometimes, 24the device being addressed via the parallel cable is a standard SCSI 25controller like an NCR 5380. The "ditto" family of external tape 26drives use the ISA replicator to interface a floppy disk controller, 27which is then connected to a floppy-tape mechanism. The vast majority 28of external parallel port devices, however, are now based on standard 29IDE type devices, which require no intermediate controller. If one 30were to open up a parallel port CD-ROM drive, for instance, one would 31find a standard ATAPI CD-ROM drive, a power supply, and a single adapter 32that interconnected a standard PC parallel port cable and a standard 33IDE cable. It is usually possible to exchange the CD-ROM device with 34any other device using the IDE interface. 35 36The document describes the support in Linux for parallel port IDE 37devices. It does not cover parallel port SCSI devices, "ditto" tape 38drives or scanners. Many different devices are supported by the 39parallel port IDE subsystem, including: 40 41 - MicroSolutions backpack CD-ROM 42 - MicroSolutions backpack PD/CD 43 - MicroSolutions backpack hard-drives 44 - MicroSolutions backpack 8000t tape drive 45 - SyQuest EZ-135, EZ-230 & SparQ drives 46 - Avatar Shark 47 - Imation Superdisk LS-120 48 - Maxell Superdisk LS-120 49 - FreeCom Power CD 50 - Hewlett-Packard 5GB and 8GB tape drives 51 - Hewlett-Packard 7100 and 7200 CD-RW drives 52 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 structured 56in two parts. There is a base pata_parport module which provides an interface 57to kernel libata subsystem, registry and some common methods for accessing 58the parallel ports. 59 60The second component is a set of low-level protocol drivers for each of the 61parallel port IDE adapter chips. Thanks to the interest and encouragement of 62Linux users from many parts of the world, support is available for almost all 63known 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 subsystem 84=============================== 85 86While configuring the Linux kernel, you may choose either to build 87the 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 DOS 93installation floppy. Alternatively, you can look at the markings on 94the adapter chip itself. That's usually sufficient to identify the 95correct device. 96 97You can actually select all the protocol modules, and allow the pata_parport 98subsystem to try them all for you. 99 100For the "brand-name" products listed above, here are the protocol 101and high-level drivers that you would use: 102 103 ================ ============ ======== 104 Manufacturer Model Protocol 105 ================ ============ ======== 106 MicroSolutions CD-ROM bpck 107 MicroSolutions PD drive bpck 108 MicroSolutions hard-drive bpck 109 MicroSolutions 8000t tape bpck 110 SyQuest EZ, SparQ epat 111 Imation Superdisk epat 112 Maxell Superdisk friq 113 Avatar Shark epat 114 FreeCom CD-ROM frpw 115 Hewlett-Packard 5GB Tape epat 116 Hewlett-Packard 7200e (CD) epat 117 Hewlett-Packard 7200e (CD-R) epat 118 ================ ============ ======== 119 120All parports and all protocol drivers are probed automatically unless probe=0 121parameter is used. So just "modprobe epat" is enough for a Imation SuperDisk 122drive to work. 123 124Manual device creation:: 125 126 # echo "port protocol mode unit delay" >/sys/bus/pata_parport/new_device 127 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 probe 134 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 will 139also need to know the unit ID number for each drive. This is usually 140the 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_device 148 149Probe parport0 using protocol epat and mode 4 (EPP-16):: 150 151 # echo "parport0 epat 4" >/sys/bus/pata_parport/new_device 152 153Probe parport0 using all protocols:: 154 155 # echo "parport0 auto" >/sys/bus/pata_parport/new_device 156 157Probe all parports using protoocol epat:: 158 159 # echo "auto epat" >/sys/bus/pata_parport/new_device 160 161Deleting devices:: 162 163 # echo pata_parport.0 >/sys/bus/pata_parport/delete_device 164 165 1663. Troubleshooting 167================== 168 1693.1 Use EPP mode if you can 170---------------------------- 171 172The most common problems that people report with the pata_parport drivers 173concern the parallel port CMOS settings. At this time, none of the 174protocol modules support ECP mode, or any ECP combination modes. 175If you are able to do so, please set your parallel port into EPP mode 176using your CMOS setup procedure. 177 1783.2 Check the port delay 179------------------------- 180 181Some parallel ports cannot reliably transfer data at full speed. To 182offset the errors, the protocol modules introduce a "port 183delay" between each access to the i/o ports. Each protocol sets 184a default value for this delay. In most cases, the user can override 185the default and set it to 0 - resulting in somewhat higher transfer 186rates. In some rare cases (especially with older 486 systems) the 187default delays are not long enough. if you experience corrupt data 188transfers, or unexpected failures, you may wish to increase the 189port delay. 190 1913.3 Some drives need a printer reset 192------------------------------------- 193 194There appear to be a number of "noname" external drives on the market 195that do not always power up correctly. We have noticed this with some 196drives based on OnSpec and older Freecom adapters. In these rare cases, 197the adapter can often be reinitialised by issuing a "printer reset" on 198the parallel port. As the reset operation is potentially disruptive in 199multiple device environments, the pata_parport drivers will not do it 200automatically. You can however, force a printer reset by doing:: 201 202 insmod lp reset=1 203 rmmod lp 204 205If you have one of these marginal cases, you should probably build 206your pata_parport drivers as modules, and arrange to do the printer reset 207before loading the pata_parport drivers. 208