From the formatter the data is streamed to either the Mark 5 disk recorder or to a tape recorder. Over the years that the VLBA telescope has been online, the tape recorders have become more expensive and harder to repair when they break down. Only recently has the cost of large hard drives come down to the point of making disk recording economically possible.

There are only 5 VLBA sites where data can still be recorded to tape. Each tape reel holds about 17,000' - over three miles - of tape. At the standard recording rate of 128 Megabits/second, a tape will last a little over 10 hrs. It is possible to record multiple observing projects at different recording rates on the same tape.

The tape is 1" wide by 16 microns thick. To give an idea as to how thin the tape is, a typical human hair is 100 microns thick - so the tape is about 1/6th as thick as a human hair!