UNIT NOT JES3 Dataset attributes change upon open

What does "UNIT NOT JES3" say about dataset allocation and formatting? I am trying to understand why a started-task seems to change the attributes of a dataset when it opens. The dataset is allocated: SPACE=(CYL,(3,1),RLSE), DCB=(LRECL=0,DSORG=PS,RECFM=U,BLKSIZ

Changing logon behavior using RACF

I work at a small company where our z9 is used just for our development and testing, not a production environment. So I sometimes am my own sysadmin, sysprog, security officer, etc. I am trying to edit my user profile so that: 1. When I logon to USS (aka OMVS), I get "bash" shell by default (

Enclave

Can anyone recommend a document describing Enclaves - as they pertain to "C" coding on S/390. Something that would compare/contrast Enclaves with Threads, including POSIX Threads. We have expertise here in Windows threading, but not so much on 390. We are trying to understand the behavior of

C function strdup

Anybody use function "strdup" (malloc & duplicate a string) from an MVS "C" program? We are using C compiler V2 R10 OS/390 C on ZOS v1.4 and we are trying to keep our code cross-platform compatible. Is strdup (string duplicate) function supported by MVS

REAL memory column in SDSF

In the SDSF DA (Display Active) there is a column labeled "REAL". What are the units? The SDSF manual states that REAL is "Current real storage usage in frames" So it seems to be in units of page-frames, but I don't know how big a frame is! 1Kbyte? Varies? Does the column give an accur