Constants

You can use four types of constants in ACS routines:

Numeric: A numeric is a string containing up to ten characters, 0 - 9. You can use numerics in comparison operations involving the &NQUAL, &NVOL, and &RETPD read-only variables, which are discussed in Read-only variables.
KB, MB: KB and MB are suffixes for numeric constants, such as 200 KB and 10 MB. One KB = 1,024 bytes while one MB = 1,048,576 bytes. Any comparison operation involving the &SIZE and &MAXSIZE read-only variables require that you use KB or MB. They are discussed in Read-only variables. The maximum prefix value for KB is 2147483647. The maximum prefix value for MB is 2097151.
Rule: When used for DASD storage, K and M normally mean 1000 and 1000000, not the values used here.
Literal: A literal is a character string, such as 'SYS1.PARMLIB', that is enclosed in single quotation marks. The maximum length of a literal is 255 characters. If you want a literal to contain a single quotation mark, such as PAYROLL'SDATA, then you must specify two single quotation marks: 'PAYROLL''SDATA'.
Mask: A mask is a character string, such as SYS1.*LIB, that is not enclosed in single quotation marks. You can use a mask to represent job names, volume serial numbers, or other system values that have a common string of characters, such as all volume serial numbers that begin with IMS™. You can also use a mask to represent data set, object or collection names that have a common string of characters.
A mask must begin with an alphabetic character, numeric character (0 - 9), national character ($, @, #), asterisk (*), or percent sign (%). The three characters “*”, “%”, and “.” have special significance in a mask. In addition, the characters "-" and "+" cannot be used in masks. These characters are reserved for use as continuation characters. The following sections describe the rules for using both the simpler masks and the slightly more involved data set masks. See FILTLIST statement for an explanation of the use of the mask characters.