EVIO

EVIO is data format and corresponding software used at JLAB.

EVIO Manual version 2.0: pdf doc.

Event Building EVIO Scheme: pdf ppt pptx.

Not in the manual yet: 8-word EVIO block(record) header:

1. block length
2. block number
3. header length=8
4. event count (# of banks, without dictionary if it is inserted)
5. not used
6. bit info[31-8] version [7-0]; if dectionary is therer, bit 8 (starting from 0) will be set
7. unused
8. magic int = 0xc0da0100

CLAS12 guidelines:

• 'EVIO BANK' (not 'EVIO SEGMENT' or 'EVIO TAGSEGMENT' will be used for data banks; bank header has 2 words, first one is exclusive bank length in words, second one contains 3 fields: tag[31:16], contentType[15:8] and num[7:0]

• no mixed formats (for example 'int' and 'short') will be allowed in the same bank, format is described in 8-bit field contentType

• BOS bank name will be replaced with 16-bit field tag, BOS bank number will be replaced with 8-bit field num

• banks description (former DDL) will be provided in some form (ASCII, Dadabase ?) which will contains a notation on every bank tag, most important will be the number of 'columns' and the meaning of every column (for example id,tdcl,adcl,tdcr,tdcl), it will help to decode data from the bank and can be used by evio viewers; will be written in the beginning of every file