Which DB access method (OSAM or VSAM) is better and why?

Answer Posted / john i harper

With IMS HALDBs, OSAM or VSAM can go to 40 terabytes, so
size is no longer a problem. However, OSAM was written by
IMS to do one thing, hold IMS data securely, and move it
quickly. VSAM was written to do many things, making the code
path longer. That increases the time needed to run, and
presents
a greater risk of failure.
Finally, OSAM is written and owned by IMS, so you only have
to ask one development team instead of two if you want any
new features added.

Is This Answer Correct ?    3 Yes 0 No



Post New Answer       View All Answers


Please Help Members By Posting Answers For Below Questions

What are the disadvantages of a hierarchical database?

2859


How many root segments do we have per database record?

707


What is the maximum number of fields allowed per segment and what is the maximum number of fields per database?

685


What is meant by bmp mode?

655


What is an ims database?

687






Explain the processing modes available in ims db?

3213


What is hierarchical database?

3284


What is meant by mpp mode?

669


What is dbdgen process?

689


What is the need for a secondary index in ims?

706


Explain the advantage of dynamic generation of acb?

2884


how to create a changeman read only audit and update only audit Specifications for the Read only Audit 1) Read HFFD database unqualified. 2) Read FDRT, FDDM, FDAP segments. If FDAP-APP-STS is ‘2’ read the FDAV segment and get the FDAV segment which has FDAV-APV-OPTION as ‘X’ If FDAP-APP-STS is ‘5’ read the HFAC database. Read the ACRT segment qualified based on the key obtained from the FDAP segment from HFFD database. Conditions for writing into output file: a. App Type should be NEWR b. App Status should be 1, 2 & 5. c. Write 50 records per app status. For e.g. first 50 records for App status 1, 2 & 5 each The output file should contain the following fields from the database FDRT-COMP-CTRY-CODE X(03). FDRT-CUST-ID-NUM X(10) FDDM-DEM-SEQ-NUM X(01) FDAP-APP-SEQ X(02) FDAP-JNT-IND X(01) FDAP-APP-STS X(01) FDAV-APV-OPTION X(01) FDAV-APV-DT X(06) FDAV-APV-AMT X(07) ACRT-ACCT-NUM X(06) ACRT-SEG-BUS-TYPE X(02) ACRT-NM1-LAST X(19) ACRT-NM1-SS X(09) ACRT-NM1-1ST X(12) ACRT-NM1-INIT X(01) ACRT-NM1-SFX X(03) ACRT-NM1-TITLE X(02) PSB – DVAN2BMP In case you get a GE for any of the conditions, write to output file along with the details of the database segment which was not found. We need to complete this whole process by tomorrow. Run the audit in DLI mode. 2) Sort the output file created in step 1 on Cust ID, Dem Seq & App Seq. Specifications for the Update Audit 3) Take the output of step 2 as input for an update audit. Details are as follows: Read each record & check the app status. If app status is less than 2 then update the FDAP-NEW- MONEY-ENT to $25000.00 PSB - AUDBMPJ The job would be a BMP job. The test job would be run in IMSE region. Note - The proc (which will be called by the job) and the job should also be present in the change-man package itself. You’ll have a test job in your PDS along with overrides to execute the program in test regions. The job would be a DLI job. The test job would be run in IMSE region. It’ll have the following steps. 1) Delete-define output and error files. 2) Use a copybook for the output layout.

3292


What information does a dbd contain?

688


What is the disadvantage of dynamic generation of acb?

668


What information does a psb contain?

677