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.

Tables

Here are some tables of accumulation rates for both kinds of subracks for various data rates and numbers of rows:

MCE data accumulation rate in Megabits per second (Mbps)

	48HP					72HP
	100 Hz	150 Hz	200 Hz	400 Hz		100 Hz	150 Hz	200 Hz	400 Hz
25 rows	1.28	1.92	2.56	5.12		2.56	3.84	5.12	10.24
33 rows	1.69	2.53	3.38	6.76		3.38	5.07	6.76	13.52
41 rows	0.94	1.42	1.89	3.78		1.42	2.83	3.78	7.56

MCE data accumulation rate in Gigabytes (10⁹ bytes) per hour

	48HP					72HP
	100 Hz	150 Hz	200 Hz	400 Hz		100 Hz	150 Hz	200 Hz	400 Hz
25 rows	0.58	0.86	1.15	2.30		1.15	1.73	2.30	4.61
33 rows	0.76	1.14	1.52	3.04		1.52	2.28	3.04	6.08
41 rows	2.10	3.15	4.20	8.40		4.20	6.30	8.40	16.79

MCE data accumulation rate in Gigabytes (10⁹ bytes) per day

	48HP					72HP
	100 Hz	150 Hz	200 Hz	400 Hz		100 Hz	150 Hz	200 Hz	400 Hz
25 rows	13.8	20.7	27.7	55.3		27.7	41.5	55.3	110.6
33 rows	18.1	27.4	36.5	73.0		36.5	54.7	73.0	146.0
41 rows	22.7	34.0	45.3	90.7		45.3	68.0	90.7	181.4