IBM Mainframe Forum

[lxw039]

can anybody explain the defference between vsam and non-vsam? PDS and catalog?
is non-vsam Isam? thank you very much!

[dick scherrer]

Hello,

can anybody explain the defference between vsam and non-vsam?

Somewhat self-explanitory (unless i misunderstand somthing with the question). If it is not vsam, it is non-vsam. The difference is that vsam is vsam and the others are not. . .but in'm not sure that is what you are asking

is non-vsam Isam?

Well, ISAM is non-vsam. . . Everything not vsam is "non-vsam". ISAM is an older technology that was basically replaced by VSAM.

PDS and catalog?

A PDS is a Partitioned Data Set. A catalog keeps track of datasets.

[lxw039]

thanks, Mr. d.
my realy meaning is what benifit we have to create vsam file,

A PDS is a Partitioned Data Set. A catalog keeps track of datasets.

can I say PDs is a file, catalog is a directory?
thanks again!

[dick scherrer]

Hello,

One of the big benefits of a vsam file is the ability to define multiple keys and access the file randomly by any of the keys.

can I say PDs is a file

Yes, a pds is a file, but a special type of file (it has partioned organization - PO).

catalog is a directory?

Basically, yes. It is a directory of where datasets are cataloged (on which volser(s)).