Data accumulation rate

This page gives some rules for estimating the accumulation rate of data on disk for a running MCE.

In general, during a regular acquisition, the data rate of an MCE is:

<math>S_w \times N_c \times N_r \times R</math>

where:

• <math>S_w</math> is the word size (=32 bits)
• <math>N_c</math> is the number of columns read (<math>=8 \times N_{RC}</math>, where <math>N_{RC}</math> is the number of readout cards used)
• <math>N_r</math> is the number of rows read
• <math>R</math> is the read-out data rate

A useful approximation is:

a single readout card reading 41 rows at 400 Hz is <math>\approx0.5</math> megabytes/second.

Here's are some tables of accumulation rates for a two readout card 48HP subrack (multiply by 2 for a full sized 72HP subrack with 4 readout cards) for various data rates and numbers of rows:

48HP subrack data accumulation rate in Gigabytes (<math>10^9</math> bytes) per hour

	100 Hz	150 Hz	200 Hz	300 Hz	400 Hz	600 Hz
25 rows	0.55	0.8	1.1	1.6	2.1	3.2
33 rows	0.7	1.1	1.4	2.1	2.8	4.2
41 rows	0.9	1.3	1.8	2.6	3.5	5.3

48HP subrack data accumulation rate in Gigabytes (<math>10^9</math> bytes) per day

	100 Hz	150 Hz	200 Hz	300 Hz	400 Hz	600 Hz
25 rows	12.9	19.3	25.7	38.6	51.5	77.2
33 rows	17.0	25.5	34.0	51.0	68.0	102.0
41 rows	21.1	31.7	42.2	63.3	84.5	126.7