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12 <refentry id='amtapetype.8'>
15 <refentrytitle>amtapetype</refentrytitle>
16 <manvolnum>8</manvolnum>
22 <refname>amtapetype</refname>
23 <refpurpose>generate a tapetype definition by testing the device directly</refpurpose>
29 <!-- body begins here -->
32 <command>amtapetype</command>
33 <arg choice='opt'>-h </arg>
34 <arg choice='opt'>-c </arg>
35 <arg choice='opt'>-f </arg>
36 <arg choice='opt'>-b <replaceable>blocksize</replaceable></arg>
37 <arg choice='opt'>-t <replaceable>typename</replaceable></arg>
38 <arg choice='opt'>-l <replaceable>label</replaceable></arg>
39 <arg choice='opt'>-o <replaceable>config_overwrite</replaceable></arg>
40 <arg><replaceable>device</replaceable></arg>
44 <refsect1><title>DESCRIPTION</title>
45 <para><emphasis remap='B'>amtapetype</emphasis>
46 generates a tapetype entry for &A; by testing the device directly</para>
49 <refsect1><title>OPTIONS</title>
50 <note><para>The options for &amtapetype; have changed in version 2.6.1</para></note>
51 <variablelist remap='TP'>
53 <term><option>-h</option></term>
55 <para>Display the help message.</para>
59 <term><option>-c</option></term>
61 <para>Run only the hardware compression detection heuristic test and stop.
62 This takes a few minutes only.</para>
66 <term><option>-f</option></term>
68 <para>Run amtapetype even if the loaded volume is already in use or compression
73 <term><option>-b</option><replaceable> blocksize</replaceable></term>
75 <para>block size to use with the device (default: 32k)</para>
79 <term><option>-t</option> <replaceable>typename</replaceable></term>
81 <para>Name to give to the new tapetype definition.</para>
85 <term><option>-l</option><replaceable> label</replaceable></term>
87 <para>Label to write on the tape (default is randomly generated).</para>
91 <term><option>-o</option> <replaceable>configoption</replaceable></term>
93 <para>See the "<emphasis remap='B'>CONFIGURATION OVERRIDE</emphasis>" section in <citerefentry><refentrytitle>amanda</refentrytitle><manvolnum>8</manvolnum></citerefentry>.</para>
99 <refsect1><title>EXAMPLE</title>
100 <para>Generate a tapetype definition for your tape device:</para>
103 <literallayout remap='.nf'>
104 % amtapetype -f /dev/nst0
105 </literallayout></refsect1>
107 <refsect1><title>NOTES</title>
108 <para>If the device cannot reliably report its comprssion status (and as of
109 this writing, no devices can do so), hardware compression is detected by
110 measuring the writing speed difference of the tape drive when writing an amount
111 of compressable and uncompresseable data. If your tape drive has very large
112 buffers or is very fast, the program could fail to detect hardware compression
113 status reliably.</para>
115 <para>Volume capacity is determined by writing one large file until an error,
116 interpereted as end-of-tape, is encountered. In the next phase, about 100
117 files are written to fill the tape. This second phase will write less data,
118 because each filemark consumes some tape. With a little arithmetic,
119 &amtapetype; calculates the size of these filemarks.</para>
121 <para>All sorts of things might happen to cause the amount of data written to
122 vary enough to generate a strange file mark size guess. A little more
123 "shoe shining" because of the additional file marks (and flushes),
124 dirt left on the heads from the first pass of a brand new tape, the
125 temperature/humidity changed during the multi-hour run, a different amount of
126 data was written after the last file mark before EOT was reported, etc.</para>
128 <para>Note that the file mark size might really be zero for whatever device this
129 is, and it was just the measured capacity variation that caused &amtapetype;
130 to think those extra file marks in pass 2 actually took up space.</para>