Mainframe, MVS and zOS Discussion

Does any one know ...what is the defination of highlighted field

It has 5 alphanumeric bytes followed by one space followed by 4 alphanumeric bytes followed by a space followed by a single alphanumeric byte.

Thanks Robert. What is the meaning of 'B' here?

Your question is easily answered by looking in the Enterprise COBOL Language Reference manual, which tells you that the PICTURE clause character B is used for

For usage DISPLAY, a character position into
which an alphanumeric space is inserted.

Picture clauses can contain: A, B, E, G, N, P, S, V, X, Z, CR, DB along with 9, 0, /, period, comma, plus, minus, asterisk, and the currency symbol. Some of these are floating, some of them are fixed, some of them can occur just once while others can occur multiple times.

Thanks Robert.

Sorry to bother you but I have not seen this kind of picture clause and was taken aback. Thank you so much for your explanation, this gives a lot more to learn.