Re rounding of cylinders etc
Ted Was that GG24-3571? MKB -- For IBM-MAIN subscribe / signoff / archive access instructions, send email to lists...@bama.ua.edu with the message: GET IBM-MAIN INFO Search the archives at http://bama.ua.edu/archives/ibm-main.html
Re: DFDSS VSAM logical restore?
If you are only looking at speeding up the re-org process (which implies KSDS only) would SORT be viable? After all, it is designed to read and write data as fast as it can - and there would be no need to actually SORT anything... Just a thought MKB -- For IBM-MAIN subscribe / signoff / archive access instructions, send email to lists...@bama.ua.edu with the message: GET IBM-MAIN INFO Search the archives at http://bama.ua.edu/archives/ibm-main.html
Alter and FreeSpace
Further to my earlier post, I delved into the pile of old manuals in the shed and found VSAM Primer and reference, G320 5774, dated 1979!! Under Section 8.8, Single/Mass Insertion, I found the following: .. Mass Insertion is a technique which is automatically used by VSAM when * Dataset is opened for output (ACB MACRF=OUT) * Sequential insertion technique is used (RPL OPTCD=SEQ) * The records to be inserted are sorted in ascending key sequence and * Are to be loaded into an empty dataset, or * Fit between 2 existing records, or * Are to be loaded at the end of a data set. ... Mass Insertion reserves defined FREESPACE and does not perform CI or CA splits (only 1 CI split is executed if records are to be inserted between existing records). This improves loading time. As there are no CI splits (except the first) this technique reduces DASD space usage dramatically. ... It is also covered (although not to the same level of detail) in DFSMS Using Data Sets. I checked z/OS 1.12 and it is in there, so I suspect it has not changed over the years. MKB -- For IBM-MAIN subscribe / signoff / archive access instructions, send email to lists...@bama.ua.edu with the message: GET IBM-MAIN INFO Search the archives at http://bama.ua.edu/archives/ibm-main.html
ALTER Freespace
A long time ago, I encountered a concept called Resume Load in VSAM. It addressed the case where multiple (two or more) records (in Ascending Key sequence) were added to a file either at its end, or between two consecutive records. In each case FreeSpace would be honoured. The former case addresses the load the file in chunks already discussed. SPEED would only apply to the first such loading. The latter case was designed to overcome the problems when a file had a trailer record which always had a higher key (often nX'FF') than the data records being inserted. This was a recognised problem with ISAM whose performance deteriorated when this situation occurred. The presence of trailer records was reputedly introduced (at least partly) by the desire to detect EOF on a sequential file rather than rely on tape drives (I am talking about the early sixties here.). Subsequently the trailer record was found to be useful in collating hash values etc and often became a part of system design, even if the file was accessed both randomly and sequentially, therefore mandating its placement on disk (when a key of low values would have been file). But old habits died hard.. At least that is how I remember it.. Others may amend the above MKB -- For IBM-MAIN subscribe / signoff / archive access instructions, send email to lists...@bama.ua.edu with the message: GET IBM-MAIN INFO Search the archives at http://bama.ua.edu/archives/ibm-main.html
Re: C-I-C-S vs KICKS
In the early days of Customer Information Control System, at a European Guide meeting held in London, I distinctly remember an Italian referring to CICS as cheeks. This was amusing in itself, but was made more so since he prefixed this with I am having trouble with my ... I freely acknowledge that his English was vastly superior to my Italian, (and French, and German, and ..) to my eternal shame. MKB -- For IBM-MAIN subscribe / signoff / archive access instructions, send email to lists...@bama.ua.edu with the message: GET IBM-MAIN INFO Search the archives at http://bama.ua.edu/archives/ibm-main.html
Re: VSAM File Updating Issues
When A KSDS CA is loaded for the first time, VSAM attempts to perform Key Compression which, usually, results in a reduction in the length of the key stored in the Sequence Set CI for that CA. In some circumstances it can result in a stored key equal or, rarely, larger than the original. The 254-byte size will obviously push things a bit, and may give some anomalous results. Some assumptions are made by IDCAMS about the expected key compression when DEFining a VSAM file (The algorithm was changed, as I recall, in z/OS 1.3). One of the consequences is that, if key compression is not as high as expected, some data CIs in a given CA are not populated because there is insufficient space in the corresponding Sequence Set record to accommodate all of the entries (one per data CI in that CA). This usually results in a file occupying more data CAs and hence more space. Again the 254 byte key (in whatever compressed state is becomes) may cause some distortion, and even some problems. Given that increasing the size of the Index CI makes the problem go away, I suspect that this is the area which should be investigated. MKB -- For IBM-MAIN subscribe / signoff / archive access instructions, send email to lists...@bama.ua.edu with the message: GET IBM-MAIN INFO Search the archives at http://bama.ua.edu/archives/ibm-main.html
Re: Jes2 Converter abend d37
Does this job execute w/o error at the vendor site? If so, what are they doing that your site does not (or vice versa)? If NOT, change vendor! (Who wants to trust/rely on a vendor who does not even test his installation deck?) Mike Kerford-Byrnes -- For IBM-MAIN subscribe / signoff / archive access instructions, send email to lists...@bama.ua.edu with the message: GET IBM-MAIN INFO Search the archives at http://bama.ua.edu/archives/ibm-main.html
Best IEFACTRT (off topic)
Following on from the instances cited already, I recall an error on the 370/155 where Convert To Binary of 100,000,001 did not work correctly. This was reported at a UK GUIDE meeting in the early seventies to a somewhat incredulous audience - so it is unlikely to be an Urban Myth. Surely there are more out there?? Mike Kerford-Byrnes -- For IBM-MAIN subscribe / signoff / archive access instructions, send email to lists...@bama.ua.edu with the message: GET IBM-MAIN INFO Search the archives at http://bama.ua.edu/archives/ibm-main.html
Re: Job Exedcution sequence
Is it feasible to combine duplicate jobnames AND Internal reader? I.E. All jobs have the same name. Step 1 of Job AAA submits Job BBB The step is always executed since there is nothing before it to abend and BBB does not start since it has the same name and AAA is already active. If Job AAA subsequently dies, BBB will still be started. Thereafter step 1 of Job BBB submits Job CCC. Etc, etc Mike Kerford-Byrnes -- For IBM-MAIN subscribe / signoff / archive access instructions, send email to lists...@bama.ua.edu with the message: GET IBM-MAIN INFO Search the archives at http://bama.ua.edu/archives/ibm-main.html
ACBUSER
Has anyone ever encountered use of (or indeed had cause to use) the ACBUSER field in a VSAM ACB? Just curious. Mike Kerford-Byrnes No virus found in this outgoing message. Checked by AVG Free Edition. Version: 7.5.516 / Virus Database: 269.21.0/1296 - Release Date: 24/02/2008 12:19 -- For IBM-MAIN subscribe / signoff / archive access instructions, send email to [EMAIL PROTECTED] with the message: GET IBM-MAIN INFO Search the archives at http://bama.ua.edu/archives/ibm-main.html
Using IARVSERV across Address Spaces
A bit late, but I have just found this when looking for something else!! It does have samples www.redbooks.ibm.com/redbooks/pdfs/sg244584.pdf Chapter 7 and Appendix D1 It may be of use Mike Kerford-Byrnes -- For IBM-MAIN subscribe / signoff / archive access instructions, send email to [EMAIL PROTECTED] with the message: GET IBM-MAIN INFO Search the archives at http://bama.ua.edu/archives/ibm-main.html
SLIPping into difficulties
It is late, I am tired and I am struggling (hopefully only for a short
while)
My problem:
Program A in Address Space 1 issues a PC to Program B in Address Space 2
four times, requesting a different function each time
Function 1 allocates memory in AS 2
Function 2 populates the memory in AS2
Function 3 gets AS2 to do some fancy processing
Function 4 depopulates the memory and frees it
Somewhere along the line the control block in AS2 which controls the memory
management gets hosed - always the same data, always the same place
I have tried the standard DC H'0' in various places but this has not
yielded fruit - it normally does.
Having used 0C1 and pretty well eliminated everything else, I have come to
the conclusion that it is the PC routine (B) in AS2 (but executing under the
TCB of AS1) that is at fault - but several hours of staring at the screen do
not show anything obvious.
So I thought I would set a SLIP trap(definitely Department of Last
Resort! - and not a feature with which I have any familiarity)
Unsure of which address space to hit, I have tried it in both, but it does
not match.
I am sure, and have checked each time that storage location 6F0C294 is being
modified TO 00038420
The PC routine is ALWAYS loaded at 669750 - 669F10 in AS2
The SLIP I coded is:
Set
slip,sa,jobname=xxx,data=(06F0c294,eq,00038420),pa=(ar,p),range=(669750,669F
10),asidsa=(''),end
How wrong is this?
Given the hour, I hope I have made a simple mistake in the SLIP. If it IS
correct, then I have another set of problems for tomorrow.
As always, the wisdom of this list is appreciated.
Mike Kerford-Byrnes
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Pause elements used across multiple address spaces
I am in the throes of designing an application that communicates between a long running (IPL to Z EOD) server Address Space and multiple user Address Spaces. Given the requirements, the exploitation of PAUSE/RELEASE seems, as per the documentation, to be highly suitable. The server Address Space is likely to deploy an array of Pause Elements from which the most suitable will be selected upon each user request (of which there may be a LOT). So a given PE may be used VERY frequently by any and/or many User Address Spaces. There is a paragraph in the Auth Assembler Guide which gives me a slight concern. It states: When a PE is allocated with auth_level=IEA_AUTHORIZED, the PE can be used to pause and release any task or SRB in the system. The same PE can be used, for example, to pause a task in address space 10. After being released, the same PE can be used to pause an SRB in, say, address space 23. ++There is, however, a small performance penalty imposed when a PE is used to pause a task or SRB in one space and then reused to pause a task or SRB in another space++. This cost is accrued upon each space transition. I have a number of questions relating to this. Does the accrual happen on each AS transition? For instance, if the usage happened to alternate between just two address spaces (say 10 23) would there be an accrual for EACH Transition, or just one per Address Space? Secondly, given the accrual rate, however derived, is there a predictable point where the performance overhead could become a liability - and how can I determine it? Finally (at least for now), if the overhead has the potential of becoming a problem, would it be a wise move to maintain a usage count of each PE and to delete and reacquire once a particular limit has been reached - and if so, any suggestions as to the values that may be suitable? Mike Kerford-Byrnes -- For IBM-MAIN subscribe / signoff / archive access instructions, send email to [EMAIL PROTECTED] with the message: GET IBM-MAIN INFO Search the archives at http://bama.ua.edu/archives/ibm-main.html
Re: Need help with Assembler accessing VSAM file in reentrant LE-conforming program
Just to eliminate the *obvious - you are in 31-bit mode, aren't you? From one who occasionally forgets. Mike Kerford-Byrnes -Original Message- From: IBM Mainframe Assembler List [mailto:[EMAIL PROTECTED] On Behalf Of Steve Comstock Sent: 16 March 2007 19:20 To: [EMAIL PROTECTED] Subject: Need help with Assembler accessing VSAM file in reentrant LE-conforming program Been working on this several days, driving me nuts. The basic setup: LE-conforming, reentrant Assembler program intended to run as a CGI and access a KSDS by key. In the program, my call to BPXWDYN is working fine. Next, I use GENCB to generate an ACB dynamically. Then I issue OPEN against that ACB: I get S0C4 that points to the next instruction after my OPEN, which is an LTR 15,15; so it looks like the abend is being generated in OPEN. The code in the vicinity: la2,genparm1 gencb blk=acb,ddname=meals,macrf=(key,dir,in), loc=any,am=vsam, rmode31=all,mf=(g,(2),genlen) ltr 15,15 jnz bad_gencb lr10,1 pick up address of built acb open ((10)),mode=31,mf=(e,openlist) ltr 15,15 The following fields are defined in a DSECT; (this DSECT is set up as part of the DSA so that addressability is provided by R13): acbstart acb am=vsam acbendds0f acblenequ acbend-acbstart ds0f genparm1 dscl(genlen) --- My guess is that actually the gencb parameters may not be correct, but I can't see it. Any suggestions for this? --- Kind regards, -Steve Comstock The Trainer's Friend, Inc. 303-393-8716 http://www.trainersfriend.com -- to be included in our opt-in list of announcements of -- new courses and other products and services from The -- Trainer's Friend, send an email to [EMAIL PROTECTED] -- For IBM-MAIN subscribe / signoff / archive access instructions, send email to [EMAIL PROTECTED] with the message: GET IBM-MAIN INFO Search the archives at http://bama.ua.edu/archives/ibm-main.html
