I will assume that this aggregate compression rate holds for the ACS era. In the following, the FOC is ignored because it is such a small part of the ingest load. The chart shows how much of the platter fill rate is due to the raw and calibrated parts of the data for each instrument. The figures are taken from the calculations for October above. The percent is the estimated percent of the compressed data that is the calibrated part.
All numbers are platters per month.
We have been compressing data for 4 months so the most recent data will not be further compressed by the secondary load process. Each optical disk holds 5.8 gigs so we will free up 136 platters by compressing the uncompressed CAL data currently in the archives. Also the total amount of the ENG and SUB data in the archives is 1045 gigs or 163 platters. We have about 15 off line platters with SUB data on them. So secondary load will free up about 148 platters by removing the rest of the ENG and SUB data from the on line archives.