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 (20 MB per buffer dump)

8 bytes per photon (18 MB per buffer dump)


 

corrtag

39 bytes per photon

39 bytes per photon

39 bytes per photon (87 MB per buffer dump)

26 bytes per photon (58 MB per buffer dump)

rawaccum

64 MB

64 MB

128 MB

2 MB


flt

160 MB

160 MB

320 MB

10 MB

x1d

0.5 MB1

0.5 MB1

1 MB2

<1 MB

fltsum

N/A

N/A

N/A

10 MB

counts

160 MB

160 MB

320 MB

10 MB

x1dsum

0.5 MB

0.5 MB

1 MB2

<1 MB

lampflash

N/A

N/A

<1 MB

<1 MB

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.

DetectorFUVNUV

Observation Mode

TIME-TAG

ACCUM

TIME_TAG

ACCUM

Pipeline-processed volume per exposure

650 MB
+ 48 bytes per photon

775 MB
+ 39 bytes per photon

25–35 MB
+ 34 bytes per photon

25–35 bytes

Standard calibrated files1

325 MB
+ 39 bytes per photon2

325 MB

15–25 MB
+ 36 bytes per photon3

15–25 MB

1 Minimum volume delivery option over the internet.
2 Approximately 70 MB per BUFFER-TIME.
3 Approximately 52 MB per BUFFER-TIME.