path: root/static/netbsd/man4/scsi.4 4.html

<table class="head">
  <tr>
    <td class="head-ltitle">SCSI(4)</td>
    <td class="head-vol">Device Drivers Manual</td>
    <td class="head-rtitle">SCSI(4)</td>
  </tr>
</table>
<div class="manual-text">
<section class="Sh">
<h1 class="Sh" id="NAME"><a class="permalink" href="#NAME">NAME</a></h1>
<p class="Pp"><code class="Nm">scsi</code>, <code class="Nm">scsibus</code>
    &#x2014; <span class="Nd">Small Computer Systems Interface (SCSI) bus
    driver</span></p>
</section>
<section class="Sh">
<h1 class="Sh" id="SYNOPSIS"><a class="permalink" href="#SYNOPSIS">SYNOPSIS</a></h1>
<p class="Pp"><code class="Cd">scsibus* at scsi?</code>
  <br/>
  <code class="Cd">atapibus* at atapi?</code>
  <br/>
  <code class="Cd">options SCSIDEBUG</code>
  <br/>
  <code class="Cd">options SCSIVERBOSE</code></p>
</section>
<section class="Sh">
<h1 class="Sh" id="DESCRIPTION"><a class="permalink" href="#DESCRIPTION">DESCRIPTION</a></h1>
<p class="Pp">The <code class="Nm">scsi</code> driver is the top,
    machine-independent layer of the two-layer software system that provides an
    interface for the implementation of drivers to control various SCSI or ATAPI
    bus devices, and to use different SCSI bus host adapters or EIDE
    controllers. SCSI bus is capable of supporting a wide variety of
    peripherals, including hard disks, removable disks, CD-ROMs, scanners, tape
    drives, and other miscellaneous high-speed devices.</p>
<p class="Pp">The bottom layer is composed of the drivers for individual EIDE or
    SCSI bus controller chips (e.g. NCR 5380), accessed through various host bus
    interfaces, including, but not limited to PCI, ISA, Sbus, TURBOchannel, and
    NuBus. These individual devices are referred to as &quot;host adaptors&quot;
    in SCSI terminology, because they connect the SCSI bus to the host
  computer.</p>
<p class="Pp">When <span class="Ux">NetBSD</span> probes the SCSI busses, it
    &quot;attaches&quot; any devices it finds to the appropriate drivers.</p>
<p class="Pp"></p>
<dl class="Bl-tag Bl-compact">
  <dt><a class="Xr">sd(4)</a></dt>
  <dd>hard disks</dd>
  <dt><a class="Xr">cd(4)</a></dt>
  <dd>CD-ROM drives</dd>
  <dt><a class="Xr">st(4)</a></dt>
  <dd>tape drives</dd>
  <dt><a class="Xr">ch(4)</a></dt>
  <dd>media changers</dd>
  <dt><a class="Xr">ss(4)</a></dt>
  <dd>scanners</dd>
</dl>
<p class="Pp">If no specific driver matches the device, then
    <code class="Nm">scsi</code> attaches the device to the
    <a class="Xr">uk(4)</a> driver so that user level SCSI
    <a class="Xr">ioctl(2)</a> calls may still be performed against the device.
    Currently, only <a class="Xr">sd(4)</a>, <a class="Xr">cd(4)</a>,
    <a class="Xr">st(4)</a>, and <a class="Xr">uk(4)</a> can attach to an atapi
    bus.</p>
<p class="Pp">Please see the <a class="Xr">intro(4)</a> manual page to see which
    SCSI bus host adaptors are supported by <span class="Ux">NetBSD</span> on
    your computer system.</p>
</section>
<section class="Sh">
<h1 class="Sh" id="KERNEL_CONFIGURATION"><a class="permalink" href="#KERNEL_CONFIGURATION">KERNEL
  CONFIGURATION</a></h1>
<p class="Pp">The <code class="Nm">scsi</code> software supports some
    <span class="Ux">NetBSD</span> kernel <a class="Xr">config(1)</a> options.
    They are:</p>
<dl class="Bl-tag">
  <dt id="SCSIDEBUG"><a class="permalink" href="#SCSIDEBUG"><code class="Dv">SCSIDEBUG</code></a></dt>
  <dd>Compile in a wide variety of
      <a class="permalink" href="#printf"><code class="Fn" id="printf">printf</code></a>()
      statements that can be turned on by <a class="Xr">ioctl(2)</a>.</dd>
  <dt id="SCSIVERBOSE"><a class="permalink" href="#SCSIVERBOSE"><code class="Dv">SCSIVERBOSE</code></a></dt>
  <dd>Enable additional and more descriptive error and status messages from the
      <code class="Nm">scsi</code> software.</dd>
</dl>
<p class="Pp">All devices and the SCSI busses support boot time allocation so
    that an upper number of devices and controllers does not need to be
    configured.</p>
<p class="Pp" id="wired">The devices are either
    <a class="permalink" href="#wired"><i class="Em">wired</i></a> so they
    appear at a particular device unit number or
    <a class="permalink" href="#counted"><i class="Em" id="counted">counted</i></a>
    so that they appear as the next available unused unit number.</p>
<p class="Pp">To configure a driver in the kernel without wiring down the device
    use a config line similar to</p>
<p class="Pp"><code class="Cd">ch* at scsibus? target ? lun ?</code></p>
<p class="Pp">to include the <a class="Xr">ch(4)</a> changer driver.</p>
<p class="Pp">To wire down a unit use a config line similar to</p>
<p class="Pp"><code class="Cd">ch1 at scsibus0 target 4 lun 0</code></p>
<p class="Pp">to assign changer 1 as the changer with SCSI ID 4, logical unit 0,
    on bus 0. Individual SCSI busses can be wired down to specific controllers
    with a config line similar to</p>
<p class="Pp"><code class="Cd">scsibus0 at ahc0</code></p>
<p class="Pp">which assigns SCSI bus 0 to the first unit using the
    <a class="Xr">ahc(4)</a> driver.</p>
<p class="Pp">When you have a mixture of wired down and counted devices then the
    counting begins with the first non-wired down unit for a particular type.
    That is, if you have a disk wired down as</p>
<p class="Pp"><code class="Cd">sd1 at scsibus0 target 1 lun 0</code></p>
<p class="Pp" id="sd2">then the first non-wired disk shall come on line as
    <a class="permalink" href="#sd2"><i class="Em">sd2</i></a>.</p>
</section>
<section class="Sh">
<h1 class="Sh" id="IOCTLS"><a class="permalink" href="#IOCTLS">IOCTLS</a></h1>
<p class="Pp">There are a number of <a class="Xr">ioctl(2)</a> calls that work
    on any SCSI device. They are defined in <span class="Pa">sys/scsiio.h</span>
    and can be applied against any SCSI device that permits them. For the tape,
    it must be applied against the control device. See the manual page for each
    device type for more information about how generic SCSI
    <a class="Xr">ioctl(2)</a> calls may be applied to a specific device.</p>
<dl class="Bl-tag">
  <dt id="SCIOCRESET"><a class="permalink" href="#SCIOCRESET"><code class="Dv">SCIOCRESET</code></a></dt>
  <dd>Reset a SCSI device.</dd>
  <dt id="SCIOCDEBUG"><a class="permalink" href="#SCIOCDEBUG"><code class="Dv">SCIOCDEBUG</code></a></dt>
  <dd>Turn on debugging. All SCSI operations originating from this device's
      driver will be traced to the console, along with other information.
      Debugging is controlled by four bits, described in the header file. If no
      debugging is configured into the kernel, debugging will have no effect.
      SCSI debugging is controlled by the configuration option
      <code class="Dv">SCSIDEBUG</code>.</dd>
  <dt id="SCIOCCOMMAND"><a class="permalink" href="#SCIOCCOMMAND"><code class="Dv">SCIOCCOMMAND</code></a></dt>
  <dd>Take a SCSI command and data from a user process and apply them to the
      SCSI device. Return all status information and return data to the process.
      The <a class="Xr">ioctl(2)</a> call will return a successful status even
      if the device rejected the command. As all status is returned to the user,
      it is up to the user process to examine this information to decide the
      success of the command.</dd>
  <dt id="SCIOCIDENTIFY"><a class="permalink" href="#SCIOCIDENTIFY"><code class="Dv">SCIOCIDENTIFY</code></a></dt>
  <dd>Ask the driver what its bus, target and LUN are.</dd>
  <dt id="SCIOCDECONFIG"><a class="permalink" href="#SCIOCDECONFIG"><code class="Dv">SCIOCDECONFIG</code></a></dt>
  <dd>Ask the device to disappear. This may not happen if the device is in
    use.</dd>
</dl>
</section>
<section class="Sh">
<h1 class="Sh" id="ADAPTERS"><a class="permalink" href="#ADAPTERS">ADAPTERS</a></h1>
<p class="Pp">The system allows common device drivers to work through many
    different types of adapters. The adapters take requests from the upper
    layers and do all IO between the SCSI bus and the system. The maximum size
    of a transfer is governed by the adapter. Most adapters can transfer 64KB in
    a single operation, however many can transfer larger amounts.</p>
</section>
<section class="Sh">
<h1 class="Sh" id="TARGET_MODE"><a class="permalink" href="#TARGET_MODE">TARGET
  MODE</a></h1>
<p class="Pp">Some adapters support
    <a class="permalink" href="#Target"><i class="Em" id="Target">Target
    Mode</i></a> in which the system is capable of operating as a device,
    responding to operations initiated by another system. Target Mode will be
    supported for some host adapters, but is not yet complete for this version
    of the SCSI system.</p>
</section>
<section class="Sh">
<h1 class="Sh" id="DIAGNOSTICS"><a class="permalink" href="#DIAGNOSTICS">DIAGNOSTICS</a></h1>
<p class="Pp">When the kernel is compiled with option
    <code class="Dv">SCSIDEBUG</code>, the <code class="Dv">SCIOCDEBUG</code>
    <a class="Xr">ioctl(2)</a> can be used to enable various amounts of tracing
    information on any specific device. Devices not being traced will not
    produce trace information. The four bits that make up the debug level, each
    control certain types of debugging information.</p>
<dl class="Bl-tag">
  <dt id="Bit"><a class="permalink" href="#Bit"><code class="Dv">Bit
    0</code></a></dt>
  <dd>shows all SCSI bus operations including SCSI commands, error information
      and the first 48 bytes of any data transferred.</dd>
  <dt id="Bit~2"><a class="permalink" href="#Bit~2"><code class="Dv">Bit
    1</code></a></dt>
  <dd>shows routines called.</dd>
  <dt id="Bit~3"><a class="permalink" href="#Bit~3"><code class="Dv">Bit
    2</code></a></dt>
  <dd>shows information about what branches are taken and often some of the
      return values of functions.</dd>
  <dt id="Bit~4"><a class="permalink" href="#Bit~4"><code class="Dv">Bit
    3</code></a></dt>
  <dd>shows more detailed information including DMA scatter-gather logs.</dd>
</dl>
</section>
<section class="Sh">
<h1 class="Sh" id="SEE_ALSO"><a class="permalink" href="#SEE_ALSO">SEE
  ALSO</a></h1>
<p class="Pp"><a class="Xr">config(1)</a>, <a class="Xr">ioctl(2)</a>,
    <a class="Xr">ata(4)</a>, <a class="Xr">cd(4)</a>, <a class="Xr">ch(4)</a>,
    <a class="Xr">intro(4)</a>, <a class="Xr">sd(4)</a>,
    <a class="Xr">se(4)</a>, <a class="Xr">ss(4)</a>, <a class="Xr">st(4)</a>,
    <a class="Xr">uk(4)</a>, <a class="Xr">scsictl(8)</a></p>
</section>
<section class="Sh">
<h1 class="Sh" id="HISTORY"><a class="permalink" href="#HISTORY">HISTORY</a></h1>
<p class="Pp">This <code class="Nm">scsi</code> system appeared in MACH 2.5 at
    TRW.</p>
<p class="Pp">This man page was originally written by Julian Elischer
    &#x27E8;julian@freebsd.org&#x27E9; for <span class="Ux">FreeBSD</span> and
    extensively modified by <span class="An">Erik Fair</span>
    &#x27E8;fair@NetBSD.org&#x27E9; for <span class="Ux">NetBSD</span>.</p>
</section>
<section class="Sh">
<h1 class="Sh" id="BUGS"><a class="permalink" href="#BUGS">BUGS</a></h1>
<p class="Pp">Not every device obeys the SCSI specification as faithfully as it
    should. As such devices are discovered by the <span class="Ux">NetBSD</span>
    Project, their names are added to a
    <a class="permalink" href="#quirk"><i class="Em" id="quirk">quirk
    list</i></a> compiled into the <code class="Nm">scsi</code> driver along a
    list of flags indicating which particular bad behaviors the device exhibits
    (and that the driver should be prepared to work around).</p>
</section>
</div>
<table class="foot">
  <tr>
    <td class="foot-date">August 18, 2019</td>
    <td class="foot-os">NetBSD 10.1</td>
  </tr>
</table>