diff options
Diffstat (limited to 'drivers/scsi/README.st')
| -rw-r--r-- | drivers/scsi/README.st | 21 |
1 files changed, 15 insertions, 6 deletions
diff --git a/drivers/scsi/README.st b/drivers/scsi/README.st index 3d14837ae..cce8d031f 100644 --- a/drivers/scsi/README.st +++ b/drivers/scsi/README.st @@ -1,5 +1,5 @@ This file contains brief information about the SCSI tape driver. -Last modified: Sun Oct 16 19:20:03 1994 by root@kai.home +Last modified: Tue Jan 10 21:32:35 1995 by root@kai.home BASICS @@ -11,8 +11,9 @@ variable block size (within buffer limits). Both the auto-rewind device number) are implemented. By default the driver writes one filemark when the device is closed after -writing. Two filemarks can be optionally written. In both cases end -of data is signified by returning zero bytes for two consecutive reads. +writing and the last operation has been a write. Two filemarks can be +optionally written. In both cases end of data is signified by +returning zero bytes for two consecutive reads. BUFFERING @@ -106,7 +107,8 @@ MTSETDRVBUFFER Sets the buffering options. The bits are the new states (enabled/disabled) of the write buffering (MT_ST_BUFFER_WRITES), asynchronous writes (MT_ST_ASYNC_WRITES), read ahead - (MT_ST_READ_AHEAD), writing of two filemark (ST_TWO_FM), and + (MT_ST_READ_AHEAD), writing of two filemark (ST_TWO_FM), + using the SCSI spacing to EOD (MT_ST_FAST_EOM), and debugging (MT_ST_DEBUGGING ; debugging must be compiled into the driver). MT_ST_WRITE_THRESHOLD @@ -128,8 +130,9 @@ MTIOCGET Returns some status information. The current block size and the density code are stored in the field mt_dsreg (shifts for the subfields are MT_ST_BLKSIZE_SHIFT and MT_ST_DENSITY_SHIFT). - The WR_PROT, BOT, EOF, EOT, EOD, and D_[800,1600,6250]_BPI - status bits reflect the tape status. The other bits are not used. + The GMT_xxx status bits reflect the drive status. GMT_DR_OPEN + is set if there is no tape in the drive. GMT_EOD means either + end of recorded data or end of tape. GMT_EOT means end of tape. MISCELLANEOUS COMPILE OPTIONS @@ -140,6 +143,12 @@ is defined. Immediate return from tape positioning SCSI commands can be enabled by defining ST_NOWAIT. +The MTEOM command is by default implemented as spacing over 32767 +filemarks. With this method the file number in the status is +correct. The user can request using direct spacing to EOD by setting +ST_FAST_EOM 1 (or using the MT_ST_OPTIONS ioctl). In this case the file +number will be invalid. + When using read ahead or buffered writes the position within the file may not be correct after the file is closed (correct position may require backspacing over more than one record). The correct position |