On 10/15/19 8:07 AM, Noel Chiappa via cctalk wrote: > I seem to recall that COBOL was the first language with support for > structures? If DIBOL has support for them too, which would be > another similarity between the two.
Both FLOW-MATIC (1953) and COMTRAN (1957) had support for data structures, though the data structure notation was not part of the program procedure. FLOW-MATIC placed the structure and naming information on data tapes (pretty novel for the period) and COMTRAN put the specification of data structure on separate fixed-field section the program input. The general idea (as explained in Grace Hopper's FLOW-MATIC description) was to make the data record structuring an independent task. She mentions being able to work out the procedure section before designing the data layout. I suspect that her record layout is one of the earliest DDLs. COBOL built on this. Looking at the procedure section of COMTRAN or FLOW-MATIC programs, there's no mistaking them as COBOL predecessors. DIBOL, not so much. COBOL, by the late 60s was a very complex language, so much so that the initial S/360 DOS releases were incomplete; they lacked support for ISAM files. Somewhere, I have an IBM document that describes the machine-language subroutines that were provided to fill the gap temporarily via the "ENTER LINKAGE" statement. I'm not at all certain that FLOW-MATIC had the first structured data description language, but it was pretty close. --Chuck
