2.5	Data Storage Requirements

Users are reminded to consider the large size of counts and flt files when allocating disk space for storing and reprocessing COS data. Additionally, corrtag files with a large number of events can be quite large. These images serve as intermediate or final calibration products from the pipeline and have the file sizes given in Megabytes in Table 2.13. Note, that these sizes are per exposure, and an associated observation set may have several exposures.

Table 2.13: COS Pipeline Data Volumes per Exposure

File Type	FUVA	FUVB	Total FUV	Total NUV	Calibrated File
rawtag	9 bytes per photon	9 bytes per photon	9 bytes per photon (18MB per BUFFER-TIME)	8 bytes per photon (16 MB per BUFFER-TIME
corrtag	35 bytes per photon	35 bytes per photon	35 bytes per photon (70 MB per BUFFER-TIME)	26 bytes per photon (52 MB per BUFFER-TIME)	•
rawaccum	64MB	64MB	128MB	2MB
flt	160MB	160MB	320MB	10MB	•
x1d	0.5MB1	0.5MB1	1MB2	<1MB	•
fltsum	N/A	N/A	N/A	10MB	•
counts	160MB	160MB	320MB	10MB	•
x1dsum	0.5MB	0.5MB	1MB2	<1MB	•
lampflash	N/A	N/A	<1MB	<1MB	•

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1

Values pertain to x1d_a or x1d_b files only. These files are temporary output products from calcos processing

2

Values are in addition to amounts given for each segment.

Similarly, users are reminded of the large cumulative size of calibrated COS spectroscopic datasets. Table 2.14 provides volume estimates for calibrated COS datasets.

Table 2.14: COS Pipeline Data Volumes per Calibrated Exposure

Detector	FUV		NUV
Observation Mode	TIME-TAG	ACCUM	TIME_TAG	ACCUM
Pipeline-processed volume per exposure	650 MB + 44 bytes per photon	775 MB + 36 bytes per photon	25-35 MB + 34 bytes per photon	25-35 bytes
Standard calibrated files1	325 MB + 35 bytes per photon2	325 MB	15-25 MB + 36 bytes per photon3	15-25 MB

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1

Minimum volume delivery option over the internet

2

Approximately 70 MB per BUFFER-TIME

3

Approximately 52 MB per BUFFER-TIME