Based on kernel version 4.16.1. Page generated on 2018-04-09 11:53 EST.
1 README file for the osst driver 2 =============================== 3 (w) Kurt Garloff <garloff@suse.de> 12/2000 4 5 This file describes the osst driver as of version 0.8.x/0.9.x, the released 6 version of the osst driver. 7 It is intended to help advanced users to understand the role of osst and to 8 get them started using (and maybe debugging) it. 9 It won't address issues like "How do I compile a kernel?" or "How do I load 10 a module?", as these are too basic. 11 Once the OnStream got merged into the official kernel, the distro makers 12 will provide the OnStream support for those who are not familiar with 13 hacking their kernels. 14 15 16 Purpose 17 ------- 18 The osst driver was developed, because the standard SCSI tape driver in 19 Linux, st, does not support the OnStream SC-x0 SCSI tape. The st is not to 20 blame for that, as the OnStream tape drives do not support the standard SCSI 21 command set for Serial Access Storage Devices (SASDs), which basically 22 corresponds to the QIC-157 spec. 23 Nevertheless, the OnStream tapes are nice pieces of hardware and therefore 24 the osst driver has been written to make these tape devs supported by Linux. 25 The driver is free software. It's released under the GNU GPL and planned to 26 be integrated into the mainstream kernel. 27 28 29 Implementation 30 -------------- 31 The osst is a new high-level SCSI driver, just like st, sr, sd and sg. It 32 can be compiled into the kernel or loaded as a module. 33 As it represents a new device, it got assigned a new device node: /dev/osstX 34 are character devices with major no 206 and minor numbers like the /dev/stX 35 devices. If those are not present, you may create them by calling 36 Makedevs.sh as root (see below). 37 The driver started being a copy of st and as such, the osst devices' 38 behavior looks very much the same as st to the userspace applications. 39 40 41 History 42 ------- 43 In the first place, osst shared its identity very much with st. That meant 44 that it used the same kernel structures and the same device node as st. 45 So you could only have either of them being present in the kernel. This has 46 been fixed by registering an own device, now. 47 st and osst can coexist, each only accessing the devices it can support by 48 themselves. 49 50 51 Installation 52 ------------ 53 osst got integrated into the linux kernel. Select it during kernel 54 configuration as module or compile statically into the kernel. 55 Compile your kernel and install the modules. 56 57 Now, your osst driver is inside the kernel or available as a module, 58 depending on your choice during kernel config. You may still need to create 59 the device nodes by calling the Makedevs.sh script (see below) manually. 60 61 To load your module, you may use the command 62 modprobe osst 63 as root. dmesg should show you, whether your OnStream tapes have been 64 recognized. 65 66 If you want to have the module autoloaded on access to /dev/osst, you may 67 add something like 68 alias char-major-206 osst 69 to a file under /etc/modprobe.d/ directory. 70 71 You may find it convenient to create a symbolic link 72 ln -s nosst0 /dev/tape 73 to make programs assuming a default name of /dev/tape more convenient to 74 use. 75 76 The device nodes for osst have to be created. Use the Makedevs.sh script 77 attached to this file. 78 79 80 Using it 81 -------- 82 You may use the OnStream tape driver with your standard backup software, 83 which may be tar, cpio, amanda, arkeia, BRU, Lone Tar, ... 84 by specifying /dev/(n)osst0 as the tape device to use or using the above 85 symlink trick. The IOCTLs to control tape operation are also mostly 86 supported and you may try the mt (or mt_st) program to jump between 87 filemarks, eject the tape, ... 88 89 There's one limitation: You need to use a block size of 32kB. 90 91 (This limitation is worked on and will be fixed in version 0.8.8 of 92 this driver.) 93 94 If you just want to get started with standard software, here is an example 95 for creating and restoring a full backup: 96 # Backup 97 tar cvf - / --exclude /proc | buffer -s 32k -m 24M -B -t -o /dev/nosst0 98 # Restore 99 buffer -s 32k -m 8M -B -t -i /dev/osst0 | tar xvf - -C / 100 101 The buffer command has been used to buffer the data before it goes to the 102 tape (or the file system) in order to smooth out the data stream and prevent 103 the tape from needing to stop and rewind. The OnStream does have an internal 104 buffer and a variable speed which help this, but especially on writing, the 105 buffering still proves useful in most cases. It also pads the data to 106 guarantees the block size of 32k. (Otherwise you may pass the -b64 option to 107 tar.) 108 Expect something like 1.8MB/s for the SC-x0 drives and 0.9MB/s for the DI-30. 109 The USB drive will give you about 0.7MB/s. 110 On a fast machine, you may profit from software data compression (z flag for 111 tar). 112 113 114 USB and IDE 115 ----------- 116 Via the SCSI emulation layers usb-storage and ide-scsi, you can also use the 117 osst driver to drive the USB-30 and the DI-30 drives. (Unfortunately, there 118 is no such layer for the parallel port, otherwise the DP-30 would work as 119 well.) For the USB support, you need the latest 2.4.0-test kernels and the 120 latest usb-storage driver from 121 http://www.linux-usb.org/ 122 http://sourceforge.net/cvs/?group_id=3581 123 124 Note that the ide-tape driver as of 1.16f uses a slightly outdated on-tape 125 format and therefore is not completely interoperable with osst tapes. 126 127 The ADR-x0 line is fully SCSI-2 compliant and is supported by st, not osst. 128 The on-tape format is supposed to be compatible with the one used by osst. 129 130 131 Feedback and updates 132 -------------------- 133 The driver development is coordinated through a mailing list 134 <osst@linux1.onstream.nl> 135 a CVS repository and some web pages. 136 The tester's pages which contain recent news and updated drivers to download 137 can be found on 138 http://sourceforge.net/projects/osst/ 139 140 If you find any problems, please have a look at the tester's page in order 141 to see whether the problem is already known and solved. Otherwise, please 142 report it to the mailing list. Your feedback is welcome. (This holds also 143 for reports of successful usage, of course.) 144 In case of trouble, please do always provide the following info: 145 * driver and kernel version used (see syslog) 146 * driver messages (syslog) 147 * SCSI config and OnStream Firmware (/proc/scsi/scsi) 148 * description of error. Is it reproducible? 149 * software and commands used 150 151 You may subscribe to the mailing list, BTW, it's a majordomo list. 152 153 154 Status 155 ------ 156 0.8.0 was the first widespread BETA release. Since then a lot of reports 157 have been sent, but mostly reported success or only minor trouble. 158 All the issues have been addressed. 159 Check the web pages for more info about the current developments. 160 0.9.x is the tree for the 2.3/2.4 kernel. 161 162 163 Acknowledgments 164 ---------------- 165 The driver has been started by making a copy of Kai Makisara's st driver. 166 Most of the development has been done by Willem Riede. The presence of the 167 userspace program osg (onstreamsg) from Terry Hardie has been rather 168 helpful. The same holds for Gadi Oxman's ide-tape support for the DI-30. 169 I did add some patches to those drivers as well and coordinated things a 170 little bit. 171 Note that most of them did mostly spend their spare time for the creation of 172 this driver. 173 The people from OnStream, especially Jack Bombeeck did support this project 174 and always tried to answer HW or FW related questions. Furthermore, he 175 pushed the FW developers to do the right things. 176 SuSE did support this project by allowing me to work on it during my working 177 time for them and by integrating the driver into their distro. 178 179 More people did help by sending useful comments. Sorry to those who have 180 been forgotten. Thanks to all the GNU/FSF and Linux developers who made this 181 platform such an interesting, nice and stable platform. 182 Thanks go to those who tested the drivers and did send useful reports. Your 183 help is needed! 184 185 186 Makedevs.sh 187 ----------- 188 #!/bin/sh 189 # Script to create OnStream SC-x0 device nodes (major 206) 190 # Usage: Makedevs.sh [nos [path to dev]] 191 # $Id: README.osst.kernel,v 1.4 2000/12/20 14:13:15 garloff Exp $ 192 major=206 193 nrs=4 194 dir=/dev 195 test -z "$1" || nrs=$1 196 test -z "$2" || dir=$2 197 declare -i nr 198 nr=0 199 test -d $dir || mkdir -p $dir 200 while test $nr -lt $nrs; do 201 mknod $dir/osst$nr c $major $nr 202 chown 0.disk $dir/osst$nr; chmod 660 $dir/osst$nr; 203 mknod $dir/nosst$nr c $major $[nr+128] 204 chown 0.disk $dir/nosst$nr; chmod 660 $dir/nosst$nr; 205 mknod $dir/osst${nr}l c $major $[nr+32] 206 chown 0.disk $dir/osst${nr}l; chmod 660 $dir/osst${nr}l; 207 mknod $dir/nosst${nr}l c $major $[nr+160] 208 chown 0.disk $dir/nosst${nr}l; chmod 660 $dir/nosst${nr}l; 209 mknod $dir/osst${nr}m c $major $[nr+64] 210 chown 0.disk $dir/osst${nr}m; chmod 660 $dir/osst${nr}m; 211 mknod $dir/nosst${nr}m c $major $[nr+192] 212 chown 0.disk $dir/nosst${nr}m; chmod 660 $dir/nosst${nr}m; 213 mknod $dir/osst${nr}a c $major $[nr+96] 214 chown 0.disk $dir/osst${nr}a; chmod 660 $dir/osst${nr}a; 215 mknod $dir/nosst${nr}a c $major $[nr+224] 216 chown 0.disk $dir/nosst${nr}a; chmod 660 $dir/nosst${nr}a; 217 let nr+=1 218 done