1SG_WRITE_LONG(8) SG3_UTILS SG_WRITE_LONG(8)
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6 sg_write_long - send the SCSI WRITE LONG command
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9 sg_write_long [--16] [--cor_dis] [--help] [--in=IF] [--lba=LBA]
10 [--pblock] [--verbose] [--version] [--wr_uncor] [--xfer_len=BTL] DEVICE
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13 Send the SCSI WRITE LONG (10 or 16 byte) command to DEVICE. The buffer
14 to be written to the DEVICE is filled with 0xff bytes or read from the
15 IF file. This buffer includes the logical data (e.g. 512 bytes) and the
16 ECC bytes.
17 This utility can be used to generate a MEDIUM ERROR at a specific logi‐
19 cal block address. This can be useful for testing error handling. Prior
20 to such a test, the sg_dd utility could be used to copy the original
21 contents of the logical block address to some safe location. After the
22 test the sg_dd utility could be used to write back the original con‐
23 tents of the logical block address. An alternate strategy would be to
24 read the "long" contents of the logical block address with sg_read_long
25 utility prior to testing and restore it with this utility after test‐
26 ing.
27 Take care: If recoverable errors are being injected (e.g. only one or a
29 few bits changed so that the ECC is able to correct the data) then care
30 should be taken with the settings in the "read write error recovery"
31 mode page. Specifically if the ARRE (for reads) and/or AWRE (for
32 writes) are set then recovered errors will cause the lba to be reas‐
33 signed (and the old location to be added to the grown defect list
34 (PLIST)). This is not easily reversed and uses the (finite number) of
35 spare sectors set aside for this purpose. If in doubt it is probably
36 safest to clear the ARRE and AWRE bits. These bits can be checked and
37 modified with the sdparm utility. For example: "sdparm -c AWRE,ARRE
38 /dev/sda" will clear the bits until the disk is rebooted.
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41 Arguments to long options are mandatory for short options as well.
42 -S, --16
44 send a SCSI WRITE LONG (16) command to DEVICE. The default
45 action (in the absence of this option) is to send a SCSI WRITE
46 LONG (10) command.
47 -c, --cor_dis
49 sets the correction disabled (i.e 'COR_DIS') bit. This inhibits
50 various other mechanisms such as automatic block reallocation,
51 error recovery and various informational exception conditions
52 being triggered. This bit is new in SBC-3 .
53 -h, --help
55 output the usage message then exit.
56 -i, --in=IF
58 read data (binary) from file named IF and use it for the SCSI
59 WRITE LONG command. If IF is "-" then stdin is read. If this
60 option is not given then 0xff bytes are used as fill.
61 -l, --lba=LBA
63 where LBA is the logical block address of the sector to over‐
64 write. Defaults to lba 0 which is a dangerous block to over‐
65 write on a disk that is in use. Assumed to be in decimal unless
66 prefixed with '0x' or has a traling 'h'. If LBA is larger than
67 can fit in 32 bits then the --16 option should be used.
68 -p, --pblock
70 sets the physical block (i.e 'PBLOCK') bit. This instructs
71 DEVICE to use the given data (unless --wr_uncor is also given)
72 to write to the physical block specified by LBA. The default
73 action is to write to the logical block corresponding to the
74 given lba. This bit is new in SBC-3 .
75 -v, --verbose
77 increase the degree of verbosity (debug messages).
78 -V, --version
80 output version string then exit.
81 -w, --wr_uncor
83 sets the "write uncorrected" (i.e 'WR_UNCOR') bit. This
84 instructs the DEVICE to flag the given lba (or the physical
85 block that contains it if --pblock is also given) as having an
86 unrecoverable error associated with it. Note: no data is trans‐
87 ferred to DEVICE, other than the command (i.e. the cdb). The
88 default action is to use the provided data (--xfer_len=BTL in
89 length) and write it to DEVICE. This bit is new in SBC-3 .
90 -x, --xfer_len=BTL
92 where BTL is the byte transfer length (default to 520). If the
93 given value (or the default) does not match the "long" block
94 size of the device, nothing is written to DEVICE and the appro‐
95 priate xfer_len value may be deduced from the error response
96 which is printed (to stderr).
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99 The LBA and BTL (transfer length) arguments may be followed by the fol‐
100 lowing multiplicative suffixes: c C *1; w W *2; b B *512; k K KiB
101 *1,024; KB *1,000; m M MiB *1,048,576; MB *1,000,000; g G GiB
102 *1,073,741,824; and GB *1,000,000,000 . Also a suffix of the form
103 "x<n>" multiplies the leading number by <n>.
104 Alternatively numerical values can be given in hexadecimal preceded by
106 either "0x" or "0X" (or with a trailing "h" or "H"). When hex numbers
107 are given, multipliers cannot be used.
108 To read from a defective sector (that, for example, has been filled
110 with 0xff bytes by this utility) use:
111 sg_dd if=DEVICE skip=LBA of=/dev/null bs=512 count=1
113 To overwrite to a defective sector use:
115 sg_dd of=DEVICE seek=LBA if=/dev/zero bs=512 count=1
117 This will result in a sector (block) with 512 bytes of 0x0 without a
119 MEDIUM ERROR since the ECC and associated data will be well formed.
120 The 10 byte SCSI WRITE LONG command limits the logical block address to
122 a 32 bit quantity. For larger lbas use the --16 option for the SCSI
123 WRITE LONG (16) command.
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126 The exit status of sg_write_long is 0 when it is successful. Otherwise
127 see the sg3_utils(8) man page.
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130 Written by Saeed Bishara. Further work by Douglas Gilbert.
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133 Report bugs to <dgilbert at interlog dot com>.
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136 Copyright © 2004-2007 Douglas Gilbert
137 This software is distributed under the GPL version 2. There is NO war‐
138 ranty; not even for MERCHANTABILITY or FITNESS FOR A PARTICULAR PUR‐
139 POSE.
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142 sg_read_long, sg_dd (both in sg3_utils), sdparm(sdparm)
143sg3_utils-1.23 January 2007 SG_WRITE_LONG(8)