sdisk(7) (RM400 only) sdisk(7)
NAME
sdisk - SCSI disk interface on an RM400
SYNOPSIS
/dev/iosb/[r]sdiskcusp
DESCRIPTION
sdisk provides SCSI magnetic and optical disk devices. SCSI disk
devices are accessed through the special files in the directory
/dev/ios0. The naming convention for all SCSI disk devices is as fol-
lows (all numbers are specified in decimal):
/dev/iosb/[r]sdiskcusp
b Bus number (always 0).
r Designates the raw (character) device.
c The logical controller number (channel ID). The controller number
is any 2-decimal number between 00 and 99. The number indicates
to which SCSI bus the device is connected.
u The device's unit number (address). The address may range from 0
to 15. For values 10 to 15 the hex representation a to f will be
used.
p Designates the disk slice (partition) (0 to 15).
MAJOR-MINOR DEVICE NUMBER
The major-minor device number may be determined via /sbin/autoconf -d
devicename.
The major-minor number is a 32-bit number formatted as follows:
BBBMMMMM MMMMMMcc cccccddd duuupppp
B Bus number (always 0).
M The major device number.
c The SCSI host adapter's controller number (channel ID).
d The SCSI device address (0 to 15) on the specified SCSI bus.
u The SCSI Logical Unit Number of the specified SCSI device, if sup-
ported. Most devices do not use LUN's, therefore bits 4-6 will
usually be 0.
p The partition number (0 to 15).
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ERROR DESCRIPTION
The error messages displayed for the IOS disk drives have the follow-
ing formats:
sdisk012s3: <cmd> Test Unit Ready
<status> 05240200 (hard 1/1) Illegal Request - CDB Illegal
Field (HP97548)
Extended Sense Bytes 18-21 for lpb at ff1b9ce0 * 00000000
or
sdisk012s3: <cmd> Write 8 <seek> [4210:8:0] <dkblk> 32 <pblk> 50528
<status> 01140200 (hard 1/1) Recovered Error - No Record
Found (HP97548)
Extended Sense Bytes 18-21 for lpb at ff18b440 * a3010002
The second error message will be described below:
sdisk012s3: The IOS disk drive in error. In this case, the disk
drive located at SCSI bus 01, drive 2, in partition 3.
<cmd> The SCSI command in error. In this case a write of
eight physical sectors was attempted.
<seek> The seek address for the write described by
[cylinder:head:sector]. Note that the seek address is
determined in one of two ways. If the SCSI request
sense command extended sense information bytes are
valid, then this value is decoded into cylinder, head,
and sector values. Otherwise the start address speci-
fied in (this case by) the SCSI write command is
decoded. In either case, the seek address does not take
into account any remapping that might have been done
previously by format. So remapping is not based upon
the seek address.
<dkblk> The 512-byte disk block start number (offset from the
current partition). In this case the eight sector write
started at block 32 in partition 3.
<pblk> The physical disk block number. Note that the physical
disk block number is determined in one of two ways. If
the SCSI request sense command extended sense informa-
tion bytes are valid, then this value is used. Other-
wise the start address specified in (this case by) the
SCSI write command is used.
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<status> KKAASSCC
The IOS composite status code. The composite status
code has the following format:
KK The SCSI Sense Key value.
AA The SCSI Additional Sense Key value.
SS The SCSI status returned to the IOS host adapter.
CC The IOS host adapter error code.
(hard 1/1) The error type, followed by the retry count. There are
two error types: hard and soft. Soft errors are
retried. Unrecoverable soft errors and errors that
should not be retried are classified as hard. The retry
count is expressed as the number of retrys divided by
the maximum retrys allowed. In the case of hard errors,
the value is always 1/1.
Recovered Error
The decoded SCSI Sense Key value message.
No Record Found
The decoded SCSI Additional Sense Key value message.
(HP97548) The disk drive type.
Extended Sense Bytes
The byte address of the saved extended sense bytes
displayed in the next lines after this message. In this
case, bytes 18 to 21 of the HP97548 disk's extended
sense data were saved after sending the SCSI request
sense command after the error on the write SCSI com-
mand.
lpb at The kernel address of the local parameter block for the
SCSI write command issued to the disk.
* a3010002 The extended sense data. The amount of data displayed
depends upon the number of saved extended sense bytes
specified for the disk type's disk profile in
/etc/conf/pack.d/space.c. Consult the manufacturer's
disk manual (request sense SCSI command) to decode
these bytes.
SCSI DISK CONFIGURATION
SCSI disk devices are identified and initialized during boot time in
the SCSI drive probe. A disk is not actually configured however, until
it has been opened. During system boot, a disk is identified solely on
the basis of its SCSI inquiry name. Once a disk has been opened, and
SCSI geometry information has been retrieved, the disk is configured.
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Disk configuration may be checked at any time via the autoconf com-
mand. Below is sample autoconf -l output:
ios0/sdisk001 HP 97548 -- HP 97548
ios0/sdisk003 CDC 94171: not configured
Following the disk name are two fields: the type, and partition names.
So, ios0/sdisk001 has a type name of HP 97548, and a partition name of
HP 97548. Disks which haven't been configured yet display a shortened
form of the SCSI inquiry name followed by an unconfigured message.
After drive spin up, the disk format and geometry parameters are
retrieved through the mode sense SCSI command. This step occurs after
the first open(2). Removable media devices are reconfigured after the
first open(2).
SCSI DISK NOTES
The physical sector size is not necessarily 512 bytes. The SCSI disk
driver converts the block count into the number of sectors required
for a 512 byte transfer. When errors occur both the physical block and
the system block size are printed. The formatter expects that the phy-
sical block will be provided, should a user wish to map out a bad
block.
REMOVABLE MEDIA DISKS
Removable media disks differ from fixed disks in that they are locked
into the drive after the first open and remain locked until after the
last close. This prevents a user from inadvertently removing the media
while the disk is still in use. Unfortunately not all removable media
SCSI disk drives support media locking, so this scheme is not fool-
proof. The last close(2) will unlock the media for possible removal,
but will not spin the drive down. After the media has been released,
subsequent open(2)s will cause the drive to re-configure. Use the
autoconf command to verify any configuration changes.
In the case of ROD (Rewritable Optical Disk) drives, two modes can be
distinguished when writing: writing with or without preceding dele-
tion. As with optical disks, all partitions extend over the entire
medium, the partition number can be used to select the operating mode.
When writing to partition 0 to 7, writing without deletion takes
place, while when writing to partition 8 to 14 this occurs with dele-
tion. Writing without deletion is only permissible if you are writing
to unwritten blocks or blocks that have already been deleted. Other-
wise, writing with deletion takes place.
SEE ALSO
autoconf(8), dkpart(8), format(8), setinfo(8), updchannelid(8).
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