ACC Utilities Reference Guide

46 Chapter2
TTGEN-ZCOMSystemTableGenerator
Creating the TTGEN Configuration File
For example
% zscan> it 0
will show information about ACC card 0.
Thefollowingparametersmaybespecifiediftheuserwishestomodify
the usage of available table space.
ttablenbr number of terminal table entries (n-32k)
The number o f terminal tables in use on an ACC card roughly
corresponds to the number of Physical Term inal Tables defined and
dynamically created for the card. If, for example, there were many
unused terminal tables, then t he space could be better utilized for I/O
buffers instead. The default value of this parameter is ACC card type
dependent.
For the Z7300A card, the minimum value n is 133.
For the Z7340A card, the minimum value n is 9.
zbufsize size of buffer entries in bytes (64-8192, multiples of 16)
The firmware on the E1/T1 and 8-channel PCI cards use fixed sized I/O
buffers to hold inbound and outbound data messages and protocol
packets. If a data message is larger than the buffer size, multiple buffers
are allocated to hold the message. The buffer size may be increased or
decreased to allow for the most common expected message size. If the
buffer size is too small then messages are fragmented by the firmware,
increasing ACC CPU overhead. If the buffer size is too large then buffer
space is being wasted by short messages. The size of the internal
header/trailer of the buffer us 16 bytes. Protocol headers are in addition
to this. The default buffer size is 160 bytes.
zbufnbr number of buffer entries (1-1M)
The maximum number of buffers available on the card. The size of each
buffer is determined by the zbufsize parameter. The default is ACC card
type dependent. For the Z7340A 8-channel PCI ACC, this parameter
should not be specified, as it will default to using all remaining free
memory for ACC buffers.