External Number Representations

As part of the I/O process all data is mapped between the internal and external representations. To do this Zebra uses the format information embedded in each bank to correctly convert integers, floating point, character and bit patterns. The external representions used are:-

      integer      2s compliment 


floating point 		  IEEE 


character 		  8-bit ASCII 


bit pattern 		  32 bit 0s and 1s

This was chosen as it is matches the internal representation on many modern 32 bit machines and so no conversion is required. This is not true for VMS so writing data on such a platform only to read it back in on the same platform involves 2 unnecessary conversions. This overhead does not appear to be too severe. In a trial generating and writing 500 5Mev electron events (approx 70K words/event - no KILLVX) version 2.05 ran 10% slower than 2.04. This has to be set in the context that asking for I/O increases the elapse time by $\sim$ 300%.

For further information see:-

.../doc/soft/machine_independent_io.doc
ZEBRA Reference Manual FZ