The TRAA Titles File

RAA is controlled by the TRAA titles bank. Currently there are no plans to place the TRAA bank in the database so the SNOMAN command file must contain:-

titles raa.dat

to load the TRAA 1 bank. This file also contains the RAAR 1 bank that defines the summary record and the subprocessor RAAS banks.

The TRAA bank contains a numbers of words that control the operation of RAA:-

• KTRAA_ENABLE_BUFFER By default RAA stores all events that pass the SAVE mode to a random access buffer from which they are subsequently restored. Setting this word to zero disables the buffer, so only the summary records remain. The ANALYSE mode proceeds as normal, although subprocessors won't be able to read back the full event of course. During RESTORE RAA calls each subprocessor for each summary record and then quits.

• KTRAA_MAX_EV_PER_FILE RAA needs to know the maximum number of events that could occur in any file when it lifts a work bank to hold all the summary records. Strictly speaking this need only be big enough to hold all the acceptable events input from a file but, as has been explained above, throwing away events during input may prevent burst subprocessors from working properly. If the memory is not big enough to hold the full buffer, RAA will accept a smaller size, down to some lower limit, but will report a warning to the effect. If a file contains more acceptable events than the buffer can hold, the excess are discarded with a ZTELL warning. The final RAA summary will count the maximum number events (acceptable or not) in any file. To avoid overflows, increase this word, and the /Z/ memory as necessary.

• KTRAA_RESTORE_DISCARDED By default RAA restores all events regardless of the setting of the DISCARD bit. This allows subsequent filters in the Programmable Event Loop to route events different ways depending on the setting of this bit (or any other in the ANAL STATUS word). Alternatively this word can be set to 0 to ignore discarded events. In this case they will not even be passed to the subprocessors in RESTORE mode.

• KTRAA_BLOCK_WORD_SIZE This defines the physical block size, in words, of the random access event buffer. It is provided in case performance is sensitive to the number. RAA always divides events up into an integral number of blocks. So decreasing the block size will reduce the amount of wasted space but increase the number of blocks written and read. The final RAA summary lists the percentage space wasted on average together with the total blocks written and read. Decreasing the value below the defaul value will result in some large events, such as muons being too large to store in the buffer and to be ignored.

• KTRAA_DELETE_PMTS When this switch is enabled all pmt style banks will be removed before the event is stored in the buffer. This vastly reduces both the size of the buffer and the ammount of IO needed by snoman. This can be combined with a reduction in KTRAA_BLOCK_WORD_SIZE to reduce the size of the buffer still further. As the PMT banks are removed after the restore phase the user will need to call both UPK and CAL again if they require the results of these processors. However the results of processors like fitters run before the save phase will not be lost, and can be acessed during the restore phase. This switch is enalbed by default. It is recommended that if this switch is turned off that the block size be increased from 256 to 1024.