Lines Matching +full:not +full:- +full:used
1 .. SPDX-License-Identifier: GPL-2.0
17 The driver is generic, i.e., it does not contain any code tailored
23 flexible method and applicable to single-user workstations. However,
32 drive performs auto-detection of the tape format well (like some
33 QIC-drives). The result is that any tape can be read, writing can be
34 continued using existing format, and the default format is used if
37 does not perform auto-detection well enough and there is a single
39 used only in variable block mode (I don't know if this is sensible
40 or not :-).
51 the configuration of mode 0 is used to provide a starting point for
55 over some of the buffering parameters not directly accessible to the
57 between formats in multi-tape operations (the explicitly overridden
60 If more than one mode is used, all modes should contain definitions
64 supported devices. The Linux SCSI tape driver does not contain such
65 tables (and will not do that in future). Instead of that, a utility
72 limits). Both the auto-rewind (minor equals device number) and
73 non-rewind devices (minor is 128 + device number) are implemented.
82 be a multiple of the block size. This is not required when reading but
99 consecutive files must be written fast. The MTWEOFI operation can be used to
102 operation is MTWEOFI, close() does not write a filemark. This can be used if
111 4. If the open option O_NONBLOCK is used, open succeeds even if the
112 drive is not ready. If O_NONBLOCK is not used, the driver waits for
113 the drive to become ready. If this does not happen in ST_BLOCK_SECONDS
124 each drive are used.
128 dev_upper non-rew mode dev-lower
129 20 - 8 7 6 5 4 0
131 The non-rewind bit is always bit 7 (the uppermost bit in the lowermost
132 byte). The bits defining the mode are below the non-rewind bit. The
134 backward compatible with the numbering used when the minor number was
143 and non-rewind entries for each mode. The names are stxy and nstxy, where x
150 if the mode is defined and zero if not defined. The files 'default_*' contain
151 the defaults set by the user. The value -1 means the default is not set. The
157 bit definitions are the same as those used with MTSETDRVBUFFER in setting the
166 directory corresponding to the mode 0 auto-rewind device (e.g., st0).
173 The following method can be used to locate the statistics that are
179 regular expression "^st[0-9]+$"
191 - The number of I/Os currently outstanding to this device.
193 - The amount of time spent waiting (in nanoseconds) for all I/O
196 movement such as when rewind on close tape devices are used.
198 - The number of I/Os issued to the tape drive other than read or
200 following calculation io_ms-read_ms-write_ms.
202 - The number of bytes read from the tape drive.
204 - The number of read requests issued to the tape drive.
206 - The amount of time (in nanoseconds) spent waiting for read
209 - The number of bytes written to the tape drive.
211 - The number of write requests issued to the tape drive.
213 - The amount of time (in nanoseconds) spent waiting for write
216 - The number of times during a read or write we found
217 the residual amount to be non-zero. This should mean that a program
219 not all data made it to tape.
224 itself is not added to the statistics until it completes.
226 The total of read_cnt, write_cnt, and other_cnt may not total to the same
230 When read the statistics may not be temporally consistent while I/O is in
238 issued by the st driver. Tape statistics do not take into account any
257 is not possible, a driver buffer allocated at run-time is used. If
258 direct i/o is not possible for the whole transfer, the driver buffer
259 is used (i.e., bounce buffers for individual pages are not
260 used). Direct i/o can be impossible because of several reasons, e.g.:
262 - one or more pages are at addresses not reachable by the HBA
263 - the number of pages in the transfer exceeds the number of
265 - one or more pages can't be locked into memory (should not happen in
273 allowed if ST_BUFFER_WRITES is non-zero and direct i/o is not used.
278 NOTE that if direct i/o is used, the small writes are not buffered. This may
280 -b option) may have had good throughput but this is not true any more with
282 is to use bigger write() byte counts (e.g., tar -b 64).
286 at the next tape operation. Asynchronous writes are not done with
287 direct i/o and not in fixed block mode.
290 problems in multivolume operations if there is not enough space on the
291 tape after the early-warning mark to flush the driver buffer.
294 attempted even if the user does not want to get all of the data at
298 Scatter/gather buffers (buffers that consist of chunks non-contiguous
299 in the physical memory) are used if contiguous buffers can't be
300 allocated. To support all SCSI adapters (including those not
304 1. The initial segment that is used for all SCSI adapters including
305 those not supporting scatter/gather. The size of this buffer will be
307 this size (and it is not larger than the buffer size specified by
308 ST_BUFFER_BLOCKS). If this size is not available, the driver halves
313 allocated so that as many segments as possible are used but the number
314 of segments does not exceed ST_FIRST_SG.
316 max_sg_segs) and the number of segments used in phases 1 and 2
317 are used to extend the buffer at run-time if this is necessary. The
318 number of scatter/gather segments allowed for the SCSI adapter is not
321 is smaller than the number of segments used in phases 1 and 2,
330 returns -1 and errno is set to ENOSPC. To enable writing a trailer,
332 bytes is returned. After this, -1 and the number of bytes are
349 tape drive if this is non-zero
352 Note that if the buffer size is changed but the write threshold is not
353 set, the write threshold is set to the new buffer size - 2 kB.
361 to use the same keyword used when loading as module but prepended
363 segments, the parameter 'st.max_sg_segs=xx' should be used (xx is the
367 versions is supported. The same keywords can be used as when loading
368 the driver as module. If several parameters are set, the keyword-value
370 used instead of the equal mark. The definition is prepended by the
375 The following syntax used by the old kernel versions is also supported::
381 - aa is the buffer size for fixed block mode in 1024 byte units
382 - bb is the write threshold in 1024 byte units
383 - dd is the maximum number of scatter/gather segments
393 (look for a package mt-st* from the Linux ftp sites; the GNU mt does
394 not open for writing for, e.g., erase).
420 Write count filemarks with immediate bit set (i.e., does not
431 Re-tension tape.
436 is used. The long erase command is used with all other values
439 Seek to tape block count. Uses Tandberg-compatible seek (QFA)
440 for SCSI-1 drives and SCSI-2 seek for SCSI-2 drives. The file and
441 block numbers in the status are not valid after a seek.
453 MT_ST_HPLOADER_OFFSET + 6, the number x is used sent to the
461 mode page but this page has not been implemented in the
474 partitions (argument non-zero). If the argument is positive,
480 LTO drives from LTO-5 upwards. The drive has to support partitions
484 Is used for several purposes. The command is obtained from count
485 with mask MT_SET_OPTIONS, the low order bits are used as argument.
514 be used for repositioning the tape (global)
516 the driver does not ask the block limits
523 the logical block number is used in
524 the MTSEEK and MTIOCPOS for SCSI-2 drives instead of
555 0xffffff means that the default is not used any more.
557 Used to set or clear the density (8 bits), and drive buffer
559 (0xfffff) the default will not be used any more. Otherwise
563 The compression default will not be used if the value of
565 contains the new default. If the bits 8-15 are set to a
566 non-zero number, and this number is not 0xff, the number is
567 used as the compression algorithm. The value
568 MT_ST_CLEAR_DEFAULT can be used to clear the compression
576 Set the long timeout that is used for operations that are
586 cleaning. The bits are device-dependent. The driver is
588 bits of the argument; must be >= 18 (values 1 - 17
590 a mask to select the relevant bits (the bits 9-16), and the
591 bit pattern (bits 17-23). If the bit pattern is zero, one
593 the pattern is non-zero, the pattern must match the masked
604 Tandberg-compatible QFA for SCSI-1 drives and the SCSI-2
605 command for the SCSI-2 drives.
612 block is -1 when it can't be determined (e.g., after MTBSF).
636 the next tape operation is not started before the previous one has
648 may not be correct after the file is closed (correct position may
653 user does not request data that far.)
663 debugging output is not voluminous. Debugging can also be enabled
668 the driver is waiting. With the command 'ps -l' you can see the state
673 ps), ps writes the function name in the WCHAN field. If not, you have