On Mon, Nov 27, 2017 at 12:48 PM, Sudershan Ravi <[email protected]> wrote:
> Why BDAM files are infrequently used? what are the complexities we face > when we do Direct Access of a file. > Off hand, I'd say that we don't use BDAM because 99% of what you can do with BDAM, you can do with an appropriate VSAM variant (KSDS, ESDS, RRN, VRRN). Enterprise COBOL does not support BDAM. BDAM is a "traditional" access method, like BSAM. So it cannot be _easily_ used by AMODE(31),RMODE(31) programs. However, VSAM is ACB based and can be easily used by AMODE(31),RMODE(31) programs. BDAM is a _basic_ access method, like BSAM. Which means that I/O is somewhat more difficult. In particular all I/O is asynchronous, so you _must_ do a CHECK macro to wait on I/O to complete. As opposed to something like QSAM where it is done for you. Again, VSAM is superior since you can do either synchronous or asynchronous I/O as you desire. > > Thanks, > Sudershan. > -- I have a theory that it's impossible to prove anything, but I can't prove it. Maranatha! <>< John McKown
