Listing of Commands Appearing in Table 3
A full listing of all of the command names and mnemonics that are executed by
Internal Disk appears in Table 7 on page 4-3. For convenience in referring to the
preceding table a list of only the commands that appear in the table is shown
below. The commands are listed in the order in which they appear in the table.
Mnemonic
Command Name
Hex
NOP
No-Operation
03
SNID
Set Path Group ID
AF
SPID
Sense Path Group ID
34
UR
Unconditional Reserve
14
RSTA
Reset Allegiance
44
RIPL
Read IPL
02
RES
Device Reserve
B4
REL
Device Release
94
SNS
Sense
04
SNSS
Sense Subsystem Status
54
RDC
Read Device Characteristics
64
SNSID
Sense ID
E4
RCD
Read Configuration Data
FA
PSF
Perform Subsystem Function
27
RSSD
Read Subsystem Data
3E
SMR
Suspend Multipath Reconnection
5B
Contingent Allegiance
Contingent allegiance is established after the channel accepts a status byte
containing unit check. In Internal Disk, the contingent allegiance may be logical
volume contingent allegiance, which impacts other LPARs attempting to use the
logical volume, or it may be subsystem contingent allegiance on behalf of a
particular LPAR and logical volume.
There are no cases in Internal Disk where a contingent allegiance at one logical
volume impacts the use of other logical volumes.
The contingent allegiance lasts until a command other than No-Op receives an
initial status byte of all zeros for the channel and logical volume that generated the
unit check, or a selective or system reset occurs.
Channel Command Retry
Channel command retry is an Internal Disk initiated action that retries a command
without an I/O interruption. When Internal Disk is ready to retry the command, it
presents device end. For channel command retry, the status byte contains:
Unit check (bit 6)
Status modifier (bit 1)
Channel end (bit 4).
If device end (bit 5) is on with the retry request, the retry is immediate. If the
control unit must delay reconnection to complete other activity before it is ready for
reconnection, device end will not be included in the retry status but will be
presented when Internal Disk is ready for reconnection.
As the control unit processes host command chains, an error can occur in the
control unit or disk subsystem, or a resource may not be available. The control unit
Chapter 2. Processing Commands and Presenting Status
2-9
Содержание Multiprise 3000
Страница 1: ...S 390 Multiprise 3000 Enterprise Server R IBM Internal Disk Subsystem Reference Guide SA22 1025 00 ...
Страница 2: ......
Страница 3: ...S 390 IBM Internal Disk Subsystem Reference Guide SA22 1025 00 ...
Страница 32: ...2 12 Internal Disk Subsystem Reference Guide ...
Страница 38: ...3 6 Internal Disk Subsystem Reference Guide ...
Страница 182: ...4 144 Internal Disk Subsystem Reference Guide ...
Страница 198: ...5 16 Internal Disk Subsystem Reference Guide ...
Страница 214: ...6 16 Internal Disk Subsystem Reference Guide ...
Страница 234: ...A 10 Internal Disk Subsystem Reference Guide ...
Страница 238: ...B 4 Internal Disk Subsystem Reference Guide ...
Страница 243: ...4 lease the Code or any copy of it Appendix C Warranties C 5 ...
Страница 244: ...C 6 Internal Disk Subsystem Reference Guide ...
Страница 248: ...D 4 Internal Disk Subsystem Reference Guide ...
Страница 254: ...X 6 Internal Disk Subsystem Reference Guide ...
Страница 263: ......
Страница 264: ...IBM Printed in the United States of America on recycled paper containing 10 recovered post consumer fiber SA22 1 25 ...