Helical scan is a way of recording information onto magnetic tape. It was used to record TV programs in the 1960s, and has been used by several storage vendors (including IBM, Exabyte, StorageTek and others) in their high-end tape-backup products. It's also the same technology used in digital audio tapes (Digital Audio Tape).
Helical scan began in the VCR world and uses a spinning read/write head and diagonal tracks. But the recording and playback heads touch the tape, and an IBM scientist concluded in the mid-1990s that helical-scan cartridges can start to deteriorate after being used from 50 to 250 times. For this reason, IBM introduced its follow-on to helical scan in 1995. Called linear technology, it doesn't store as much data as helical scan but the heads don't touch the tape. Helical scan remains a viable option for high-capacity tape backup.