Most of the following compile options can be overridden with boot/module parameters and/or runtime configuration (i.e. ioctls).

The following parameters are defined in linux/drivers/scsi/st_options.h

ST_NOWAIT                    {0}
ST_IN_FILE_POS               {0}
ST_RECOVERED_WRITE_FATAL     {0}
ST_DEFAULT_BLOCK             {0}
ST_BUFFER_BLOCKS             {32}
ST_WRITE_THRESHOLD_BLOCKS    {30}
ST_MAX_BUFFERS               {4}
ST_MAX_SG                    {16}
ST_FIRST_SG                  {8}
ST_FIRST_ORDER               {5}
ST_TWO_FM                    {0}
ST_BUFFER_WRITES             {1}
ST_ASYNC_WRITES              {1}
ST_READ_AHEAD                {1}
ST_AUTO_LOCK                 {0}
ST_FAST_MTEOM                {0}
ST_SCSI2LOGICAL              {0}
ST_SYSV                      {0}

The following parameters are defined in linux/drivers/scsi/st.c

ST_TIMEOUT                   {900*HZ}
ST_LONG_TIMEOUT              {14000*HZ}

The Linux tape interface is defined in /usr/src/linux/include/linux/mtio.h .

The following ioctl()s are listed in alphabetical order with a brief explanation to the right. [See st documentation (especially man 4 st) for more details.]

MTIOCTOP   [execute tape commands and set drive/driver options]
MTIOCGET   [get the status of the drive]
MTIOCPOS   [get the current tape location]

open()   O_RDONLY, O_RDWR
close()
read()
write()
ioctl()