A - Page 1 - ----------------------------------------------------------------------- | README file for DAB V6.2A | | Edition: January 2000 | ----------------------------------------------------------------------- This README file describes the changes/extensions in DAB V6.2A compared with DAB V6.1A. The changes/extensions refer to the manual DAB V6.1A Edition August 1999 Order number: U2431-J-Z125-11-76 Overview of changes and extensions ================================== With the exception of the changes/extensions described below, DAB V6.2A has the same functionality as DAB V6.1A. DAB V6.2A can be run as of BS2000/OSD-BC V4.0 and only on SR2000 systems (with SINIX2000 V8.0). It replaces DAB V6.1A on these systems. Contents ======== 1. Cache medium expanded storage (ES) ....................... Page 2 1.1 DAB V6.2A in multisystem operation ....................... Page 2 1.2 Releasing ES cache buffers ............................... Page 3 2. Cache medium main memory (MM) ............................ Page 3 3. Installation of DAB V6.2A ................................ Page 3 4. Changes to commands ...................................... Page 4 5. New messages ..............................................Page 4 A - Page 2 - 1. Cache medium expanded storage (ES) ======================================= (see the "DAB V6.1A" manual, pages 4 and 16) DAB V6.2A supports a new cache medium for SR2000 systems: expanded storage (ES). This storage type is not identical with the expanded storage for 390 systems supported up to DAB V6.0A. Additional main memory space is used as a physical storage medium for ES. Both ES and main memory are volatile cache media whose data is no longer available after a power outage or a system crash. This makes ES suitable primarily for read caching and only of limited use as a cache medium for write and read/write caching. ES is configured as part of the main memory belonging to an SR2000 system and is neither used by SINIX2000 itself nor made available to BS2000 as main memory. These configuration functions are available as of SINIX2000 V8 (see section 8.17 of the manual "SINIX2000 V7.5/V8, Installation, Operation and Administration", Edition November 1999 (order number U24789-J-Z385-3-76)). Prior to this, DAB is the only user of this storage medium. The highlights of this cache storage are: - Those areas of main memory above the 2Gb boundary on an SR2000 system can also be used as DAB cache storage. DAB can make use of up to 8 Gbytes of expanded storage for caching. - Special SINIX2000 software for data transfer between ES and BS2000 main memory (average I/O time: approx. 0.1 ms) enables highly efficient access to expanded storage. 1.1 DAB V6.2A in multisystem operation ---------------------------------------- (see the "DAB V6.1A" manual, pages 31-37: the term "multiprocessor operation" should be replaced by "multisystem operation", since "multiprocessor" refers to a single computer with more than 1 processor, whereas "multisystem" refers to a complex of at least two computers which are connected through a network) (see the "DAB V6.1A" manual, page 33/34) DAB caching of the data areas of a shared pubset for a homogeneous CCS network is also supported for DAB V6.2A. In this context, caching in ES is exactly the same as caching in main memory. If a pubset is to be cached using the subsystem DAB, DAB has to be active on all node systems involved. For this a configuration with DAB V6.1A on /390 systems and DAB V6.2A on SR2000 systems is permitted. A - Page 3 - 1.2 Releasing ES cache buffers ------------------------------- (see the "DAB V6.1A" manual, page 38/39) The cache medium ES can be used to set up very large cache buffers. This means that destaging (writing cache data to disk) such large ES cache buffers when using (read-)write caching mode (both ADM-PFA and PFA) may take a correspondingly long time. 2. Cache medium main memory (MM) ================================== (see the "DAB V6.1A" manual, pages 4 and 15) For main memory, access times for main memory caches on SR2000 systems have been considerably improved (average I/O time: approx. 0.1 ms). This results in the same I/O times as for systems of type 390. The I/O times for main memory caches and expanded storage caches are identical. 3. Installation of DAB V6.2A ============================== (see the "DAB V6.1A" manual, page 74) All the information in this section referring to DAB V6.1A can, once the version number has been changed (062 instead of 061), also be applied to DAB V6.2A. Exception: SYSLNK.DAB.062 is not delivered. The following two files are additionally delivered: - SYSRME.DAB.062.D DAB README file, German - SYSRME.DAB.062.E DAB README file, English Note: The subsystem DAB V6.2A can be loaded only if SINIX2000 V8.0 is installed. A - Page 4 - 4. Changes to commands ======================== SHOW-CACHE-CONFIGURATION ------------------------ The SHOW-CACHE-CONFIGURATION command provides information about the available ES storage if no PFA cache buffer has yet been created in ES. In this case only the partition configuration record, which shows the available (and free) ES size, is displayed, and output in S variables only generates the data of the partition configuration record. SHOW-DAB-CACHING ---------------- The SHOW-DAB-CACHING command similarly provides information about the available ES storage if no cache buffer has yet been created in ES. The information is displayed by message NDB0128, followed by message NDB0069. No S variables are created in this case. (If the cache buffer has already been created in ES, the free ES size is displayed together with the data of a cache buffer as usual.) Example: /SHOW-DAB-CACHING CACHE-MEDIUM=*ES % NDB0128 '8192'MB EXPANDED STORAGE AVAILABLE FOR DAB % NDB0069 NO DAB CACHE BUFFER ACTIVE IN CACHE MEDIUM 'ES' 5. New messages ================= NDB0037 PARAMETER ERROR IN /START-DAB-CACHING COMMAND: NO ES PARTITION IS AVAILABLE FOR DAB. COMMAND NOT PROCESSED Response Correct the parameter specification. NDB0128 '(&00)' MB EXPANDED STORAGE AVAILABLE FOR DAB NDB0129 PARAMETER ERROR IN MODIFY-DAB-CACHING COMMAND: MODIFICATION OF THE CACHE SEGMENT SIZE OF A CACHE BUFFER WITHOUT A CACHE STORAGE ASSIGNED TO IT IS NOT POSSIBLE Meaning There is no cache storage assigned to the cache buffer whose segment size is to be changed. This error situation may be caused by a malfunction of a former MODIFY-DAB-CACHING command for this cache buffer. Response Please expand the cache storage again.