| Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1 | /* |
| 2 | The compile-time configurable defaults for the Linux SCSI tape driver. |
| 3 | |
| 4 | Copyright 1995-2003 Kai Makisara. |
| 5 | |
| 6 | Last modified: Mon Apr 7 22:49:18 2003 by makisara |
| 7 | */ |
| 8 | |
| 9 | #ifndef _ST_OPTIONS_H |
| 10 | #define _ST_OPTIONS_H |
| 11 | |
| 12 | /* If TRY_DIRECT_IO is non-zero, the driver tries to transfer data directly |
| 13 | between the user buffer and tape drive. If this is not possible, driver |
| 14 | buffer is used. If TRY_DIRECT_IO is zero, driver buffer is always used. */ |
| 15 | #define TRY_DIRECT_IO 1 |
| 16 | |
| 17 | /* The driver does not wait for some operations to finish before returning |
| 18 | to the user program if ST_NOWAIT is non-zero. This helps if the SCSI |
| 19 | adapter does not support multiple outstanding commands. However, the user |
| 20 | should not give a new tape command before the previous one has finished. */ |
| 21 | #define ST_NOWAIT 0 |
| 22 | |
| 23 | /* If ST_IN_FILE_POS is nonzero, the driver positions the tape after the |
| 24 | record been read by the user program even if the tape has moved further |
| 25 | because of buffered reads. Should be set to zero to support also drives |
| 26 | that can't space backwards over records. NOTE: The tape will be |
| 27 | spaced backwards over an "accidentally" crossed filemark in any case. */ |
| 28 | #define ST_IN_FILE_POS 0 |
| 29 | |
| 30 | /* If ST_RECOVERED_WRITE_FATAL is non-zero, recovered errors while writing |
| 31 | are considered "hard errors". */ |
| 32 | #define ST_RECOVERED_WRITE_FATAL 0 |
| 33 | |
| 34 | /* The "guess" for the block size for devices that don't support MODE |
| 35 | SENSE. */ |
| 36 | #define ST_DEFAULT_BLOCK 0 |
| 37 | |
| 38 | /* The minimum tape driver buffer size in kilobytes in fixed block mode. |
| 39 | Must be non-zero. */ |
| 40 | #define ST_FIXED_BUFFER_BLOCKS 32 |
| 41 | |
| 42 | /* Maximum number of scatter/gather segments */ |
| 43 | #define ST_MAX_SG 256 |
| 44 | |
| 45 | /* The number of scatter/gather segments to allocate at first try (must be |
| 46 | smaller or equal to the maximum). */ |
| 47 | #define ST_FIRST_SG 8 |
| 48 | |
| 49 | /* The size of the first scatter/gather segments (determines the maximum block |
| 50 | size for SCSI adapters not supporting scatter/gather). The default is set |
| 51 | to try to allocate the buffer as one chunk. */ |
| 52 | #define ST_FIRST_ORDER 5 |
| 53 | |
| 54 | |
| 55 | /* The following lines define defaults for properties that can be set |
| 56 | separately for each drive using the MTSTOPTIONS ioctl. */ |
| 57 | |
| 58 | /* If ST_TWO_FM is non-zero, the driver writes two filemarks after a |
| 59 | file being written. Some drives can't handle two filemarks at the |
| 60 | end of data. */ |
| 61 | #define ST_TWO_FM 0 |
| 62 | |
| 63 | /* If ST_BUFFER_WRITES is non-zero, writes in fixed block mode are |
| 64 | buffered until the driver buffer is full or asynchronous write is |
| 65 | triggered. May make detection of End-Of-Medium early enough fail. */ |
| 66 | #define ST_BUFFER_WRITES 1 |
| 67 | |
| 68 | /* If ST_ASYNC_WRITES is non-zero, the SCSI write command may be started |
| 69 | without waiting for it to finish. May cause problems in multiple |
| 70 | tape backups. */ |
| 71 | #define ST_ASYNC_WRITES 1 |
| 72 | |
| 73 | /* If ST_READ_AHEAD is non-zero, blocks are read ahead in fixed block |
| 74 | mode. */ |
| 75 | #define ST_READ_AHEAD 1 |
| 76 | |
| 77 | /* If ST_AUTO_LOCK is non-zero, the drive door is locked at the first |
| 78 | read or write command after the device is opened. The door is opened |
| 79 | when the device is closed. */ |
| 80 | #define ST_AUTO_LOCK 0 |
| 81 | |
| 82 | /* If ST_FAST_MTEOM is non-zero, the MTEOM ioctl is done using the |
| 83 | direct SCSI command. The file number status is lost but this method |
| 84 | is fast with some drives. Otherwise MTEOM is done by spacing over |
| 85 | files and the file number status is retained. */ |
| 86 | #define ST_FAST_MTEOM 0 |
| 87 | |
| 88 | /* If ST_SCSI2LOGICAL is nonzero, the logical block addresses are used for |
| 89 | MTIOCPOS and MTSEEK by default. Vendor addresses are used if ST_SCSI2LOGICAL |
| 90 | is zero. */ |
| 91 | #define ST_SCSI2LOGICAL 0 |
| 92 | |
| 93 | /* If ST_SYSV is non-zero, the tape behaves according to the SYS V semantics. |
| 94 | The default is BSD semantics. */ |
| 95 | #define ST_SYSV 0 |
| 96 | |
| 97 | /* Time to wait for the drive to become ready if blocking open */ |
| 98 | #define ST_BLOCK_SECONDS 120 |
| 99 | |
| 100 | #endif |