Archive for September, 2010
Pageable Link Pack Area (PLPA)
Posted by Rui Miguel Feio in Glossary, MVS, Tech - Mainframe on September 4, 2010
- It’s defined in SYS1.PARMLIB(LPALSTxx).
- It’s an area of Common Storage that is loaded at IPL time.
- This area contains SVC routines, access methods, and other READ-ONLY System Programs, along with any READ-ONLY reenterable user programs selected by an installation that can be shared among users of the system.
- There cannot be PDS/E data sets in the LPALST concatenation.
- Modules must be reenterant and executable.
- Programs in the PLPA are shared among users of the system.
- It is desirable to place all frequently used refreshable SYS1.LINKLIB and SYS1.CMDLIB modules in the PLPA.
- ASM maintains records that have pointers to the PLPA and Extended PLPA pages in the PLPA data set.
- During quick-start or warm-start IPLs, the system uses the pointers to locate the PLPA and Extended PLPA pages. The system then rebuilds the PLPA and Extended PLPA page tables, and uses them for the current IPL.
- If CLPA is specified during the IPL, a Cold start is then performed. The PLPA storage is deleted and made available for system paging use. A new PLPA and Extended PLPA are then loaded, and pointers to the PLPA and Extended PLPA pages are recorded in the PLPA page data set.
- The LPALST concatenation can have up to 255 extents. If you specify more data sets than the concatenation can contain, the system truncates the LPALST concatenation and issues messages that indicate which data sets were not included in the concatenation.
Contents:
- PLPA and Extended PLPA contain all the members of SYS1.LPALIB and any other libraries that are specified in the active LPALSTxx.
- The modules must be refreshable.
- Load modules with RMODE 24 are placed in the PLPA (below the “line”), while those with RMODE of any are placed in the Extended PLPA (above the “line”).
- If one or more LPALSTxx members exist, and the system can open the specified data sets successfully, the system uses the LPALST concatenation to build the PLPA (during Cold starts and IPLs that include the CLPA option). Otherwise the system builds the PLPA from only those modules named in the SYS1.LPALIB.
Link Pack Area (LPA)
Posted by Rui Miguel Feio in Glossary, MVS, Tech - Mainframe on September 4, 2010
- It’s a common Virtual Storage Area.
- It’s non-getmainable.
- It’s built at IPL time by loading Load modules contained in SYS1.LPALIB and its concatenations.
- There are 2 LPAs: one above “the line” (16MB) and the other below depending on the residence mode of the load module.
- Because the Load modules are in the Common Area they are shared by all address spaces in the system.
- Modules have to be re-entrant, ie, modules that can be executed concurrently by several tasks but which cannot be modified.
- Modules in LPA reside in Virtual Storage.
- By placing module data sets in LPA, you can obtain improved MVS system performance.
- LPA consists of:
“Pirate Latitudes” – Book Review
Posted by Rui Miguel Feio in Books on September 3, 2010
Author: Michael Crichton
I admit Michael Crichton is my favourite writer. It’s a shame that he has passed away. I simply love his books.
However, when “Pirate Latitudes” first came out I was not entirely convinced if this would be the type of book I would want to read. A book about pirates? Now come on, in the past few years we’ve been bombarded with Pirates. In nowadays, when you think of Pirates, you think of Pirates of the Caribbean with Captain Jack Sparrow, Captain Hector Barbossa, Will Turner and the rest of the gang.
Having this in mind I wasn’t sure if Michael Crichton would be able to bring something new to the subject and captivate my attention and most of all, my imagination!
Oh, I was wrong! I was so, so wrong! After reading “Pirates Latitude” when I now think of Pirates, I still think of Jack Sparrow, but I also think of Captain Hunter, Lazue, Sanson, the Moor…
“Pirates Latitude” is a fantastic book! Michael Crichton as always, is able to take your mind to the worlds he imagined, and this time, the world was swarming with pirates!
A must buy book! Definitely!
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Story
Pirate Latitudes takes the reader back to 1665, when Charles II’s Jamaican colony is under serious threat, besieged on every side by the voracious Spanish empire. At the centre of this troubled outpost is its crowded capital, Port Royal, a lively (if festering) hangout for criminal dregs, who inhabit its taverns and brothels. This is the time of the privateer, when (with tacit royal sanction), ship’s captains could make sorties against Spanish ships and outposts, plundering at will — just so long as the Governor and King Charles are taken care of. Michael Crichton’s protagonist in this colourful mix is Captain Charles Hunter, educated at Harvard and a man with keenly developed survival instincts. He is made aware a treasure galleon, which is at anchor in the heavily fortified Spanish island of Matanceros, and Hunter’s interest is piqued — not least because this means he will be able to take on Philip of Spain’s most ruthless enforcer, Cazalla. The stage is set for what will either be a glorious bit of naval smash-and-grab or that will end in the ignominious death of Charles Hunter and his motley crew.
Display all the Storage Groups
Posted by Rui Miguel Feio in Storage, Tech - Mainframe on September 3, 2010
To display all the Storage Groups of the currently active SMS configuration, we use the command:
D SMS,SG(ALL)
Example:
D SMS,SG(ALL)
IGD002I 15:24:57 DISPLAY SMS 749
STORGRP TYPE SYSTEM= 1
SGTSTVL POOL +
SGDB2VL POOL +
DUMMY DUMMY .
SGOVRFL POOL *
SGTAPE TAPE +
***************************** LEGEND *****************************
. THE STORAGE GROUP OR VOLUME IS NOT DEFINED TO THE SYSTEM
+ THE STORAGE GROUP OR VOLUME IS ENABLED
- THE STORAGE GROUP OR VOLUME IS DISABLED
* THE STORAGE GROUP OR VOLUME IS QUIESCED
D THE STORAGE GROUP OR VOLUME IS DISABLED FOR NEW ALLOCATIONS ONLY
Q THE STORAGE GROUP OR VOLUME IS QUIESCED FOR NEW ALLOCATIONS ONLY
> THE VOLSER IN UCB IS DIFFERENT FROM THE VOLSER IN CONFIGURATION
SYSTEM 1 = SYST
Display the status of a storage group
Posted by Rui Miguel Feio in Storage, Tech - Mainframe on September 2, 2010
If you come across the need to check the status of a storage group then you can use the MVS command:
D SMS,SG(storage_group)
For example:
storage group name: STGTSTVL
RESPONSE=SYST
IGD002I 15:17:43 DISPLAY SMS 939
STORGRP TYPE SYSTEM= 1
SGTSTVL POOL +
***************************** LEGEND *****************************
. THE STORAGE GROUP OR VOLUME IS NOT DEFINED TO THE SYSTEM
+ THE STORAGE GROUP OR VOLUME IS ENABLED
- THE STORAGE GROUP OR VOLUME IS DISABLED
* THE STORAGE GROUP OR VOLUME IS QUIESCED
D THE STORAGE GROUP OR VOLUME IS DISABLED FOR NEW ALLOCATIONS ONLY
Q THE STORAGE GROUP OR VOLUME IS QUIESCED FOR NEW ALLOCATIONS ONLY
> THE VOLSER IN UCB IS DIFFERENT FROM THE VOLSER IN CONFIGURATION
SYSTEM 1 = SYST
If you would like to list the volumes that are part of the Storage Group, you would then issue the command:
D SMS,SG(SGTSTVL),LISTVOL
IGD002I 15:20:50 DISPLAY SMS 737
STORGRP TYPE SYSTEM= 1
SGTSTVL POOL +
VOLUME UNIT SYSTEM= 1 STORGRP NAME
TST001 5B22 + SGTSTVL
TST002 5B23 + SGTSTVL
TST003 5B24 + SGTSTVL
***************************** LEGEND *****************************
. THE STORAGE GROUP OR VOLUME IS NOT DEFINED TO THE SYSTEM
+ THE STORAGE GROUP OR VOLUME IS ENABLED
- THE STORAGE GROUP OR VOLUME IS DISABLED
* THE STORAGE GROUP OR VOLUME IS QUIESCED
D THE STORAGE GROUP OR VOLUME IS DISABLED FOR NEW ALLOCATIONS ONLY
Q THE STORAGE GROUP OR VOLUME IS QUIESCED FOR NEW ALLOCATIONS ONLY
> THE VOLSER IN UCB IS DIFFERENT FROM THE VOLSER IN CONFIGURATION
SYSTEM 1 = SYST
Display system connectivity of the tape and optical libraries
Posted by Rui Miguel Feio in Storage, Tech - Mainframe on September 2, 2010
If you wish to display which libraries are connected to your system you can use the MVS command:
D SMS,LIB(ALL)
Example:
D SMS,LIB(ALL)
RESPONSE=SYST
IGD002I 15:10:50 DISPLAY SMS 869
LIBRARY CLASS SYSTEM= 1
TSTATL1 TAPE +
***************************** LEGEND *****************************
. THE LIBRARY IS NOT DEFINED TO THE SYSTEM
+ THE LIBRARY IS ONLINE
- THE LIBRARY IS OFFLINE
P THE LIBRARY IS PENDING OFFLINE
SYSTEM 1 = SYST
We can see in this example that we have a tape library online on system SYST called TSTATL1. If we wish to obtain more details regarding this library we issue the command:
D SMS,LIB(TSTATL1),DETAIL
CBR1110I OAM library status: 563
TAPE LIB DEVICE TOT ONL AVL TOTAL EMPTY SCRTCH ON OP
LIBRARY TYP TYPE DRV DRV DRV SLOTS SLOTS VOLS
TSTATL1 AL 3584-L22 16 4 4 1060 187 148 Y Y
----------------------------------------------------------------------
MEDIA SCRATCH SCRATCH SCRATCH
TYPE COUNT THRESHOLD CATEGORY
MEDIA5 148 50 0005
----------------------------------------------------------------------
LIBRARY ID: A0669
OPERATIONAL STATE: AUTOMATED
ERROR CATEGORY SCRATCH COUNT: 9
----------------------------------------------------------------------
Convenience I/O station installed.
Convenience I/O station in Input mode.
Convenience I/O station Empty.
Bulk input/output not configured.
How to check if a volume is SMS-managed
Posted by Rui Miguel Feio in Storage, Tech - Mainframe on September 2, 2010
One of the ways (and probably the easiest) to check if a volume is SMS-managed is by using the MVS command:
D SMS,VOL(volser)
Here’s an example:
volume: TST001
Command:
D SMS,VOL(TST001)
The result would be:
RESPONSE=SYST
IGD002I 09:52:24 DISPLAY SMS 382
VOLUME UNIT SYSTEM= 1 STORGRP NAME
TST001 5B22 + SGTSTVL
***************************** LEGEND *****************************
. THE STORAGE GROUP OR VOLUME IS NOT DEFINED TO THE SYSTEM
+ THE STORAGE GROUP OR VOLUME IS ENABLED
- THE STORAGE GROUP OR VOLUME IS DISABLED
* THE STORAGE GROUP OR VOLUME IS QUIESCED
D THE STORAGE GROUP OR VOLUME IS DISABLED FOR NEW ALLOCATIONS ONLY
Q THE STORAGE GROUP OR VOLUME IS QUIESCED FOR NEW ALLOCATIONS ONLY
> THE VOLSER IN UCB IS DIFFERENT FROM THE VOLSER IN CONFIGURATION
SYSTEM 1 = SYST
As we can see from the display, volume TST001 has the unit address 5B22 and is part of the Storage Group SGTSTVL, meaning it’s SMS managed.
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