BUFCAP


   .-BUFCAP--=--1--------------.   
>>-+---------------------------+-------------------------------><
   '-BUFCAP--=--number_of_pius-'

statements:

GROUP, LINE

dependencies:

VTAM® only

range:

1–255

Specifies the maximum number of PIUs that can be read at one time from a line without retransmissions, assuming each PIU is the maximum length allowed (MAXBFRU(MAX)×IOBUFSIZE). If an individual PIU length is smaller than the maximum size allowed for a PIU, more PIUs than BUFCAP's value could be read in. The greatest number of buffers that VTAM will allocate is BUFCAP×MAXBFRU(MAX).

A retry value of 0 will not allow a type 2.0 or type 2.1 connection to become active. One retry is required to build the XID that will be exchanged.

Note: No matter what value you give for BUFCAP, VTAM uses only as many buffers as necessary to read in all incoming data.

For example, suppose that after initial startup, BUFCAP=35, IOBUFSIZE=100, MAXBFRU=(2,8), and all the PIUs are maximum size (each PIU would be 800 bytes long, requiring eight buffers). The NCP sends only MAXOUT PIUs at one time. If MAXOUT=7, the number of buffers required to have no retransmissions is 56. The BUFCAP operand allows up to 280 (35 × 8), but they will not be used.