Still, tape remains part of backup in many shops. It's the primary backup medium at 25 percent of enterprises surveyed by ESG, and it's used for backup at 56 percent of the surveyed sites, Buffington said. By comparison, only 2 percent of enterprises said they back up directly to cloud storage.
Tape survives partly due to inertia, says Pund-IT analyst Charles King.
"A lot of it has to do with prior use and existing infrastructure investments," King says. "You've put millions of dollars into it, and it's cheaper to keep the old stuff rolling than it is to migrate to a new system."
However, tape retains the edge over HDDs and flash in many cases. Tape cartridges cost well under $100 and hold terabytes of data. They also consume less power than HDDs because they don't have to be kept spinning. When it comes to transporting very large amounts of data, shipping tapes overnight can be faster and cheaper than using a fat wide-area network pipe.
The classic use case for tape now is long-term data retention, such as holding on to tax returns or medical records. Once they go onto a tape cartridge, those files can sit for years without needing any electricity or drive maintenance.
"If you're going to do that with any kind of scale and any kind of economics, you're going to use tape," ESG's Buffington said.
That type of storage often takes the form of archiving, where it's not an extra copy of the data being stored for recovery but the primary copy of old data that may be rarely used.
"We're seeing tape really change the use case from more of a backup and recovery medium to more of an archive medium," IDC's Amatruda said.
Meanwhile, tape's speed and ease of use are improving. One key advance is Linear Tape File System (LTFS), a standard way of indexing the contents of a tape cartridge within the tape itself. The robotic systems that retrieve tapes used to rely solely on the date when the tape was made. LTFS collects all the information about what's on the tape and includes it there.
"A tape cartridge itself becomes a gigantic USB drive, if you will," IBM's Tripathi said.
That capability can also be expanded to an entire library of data with a system such as IBM's LTFS Library Edition. It will collect the metadata from all the tapes so IT departments can search for and retrieve an individual file from within an entire library, Tripathi said.
LTFS is now used by most major tape vendors, so products of different brands can work together. The backers of NTFS are now seeking to make it a formal standard of the Storage Networking Industry Association, a step that may be completed next year.
Tape is also growing more space efficient, with a standard cartridge based on the new LTO-6 specification holding 2.5TB of data without compression or 6.25TB with compression.
LTO-6 drives can transfer data at 400MB per second. Tape falls behind on speed mainly when it comes to seeking out many small, separate files, said Henry Baltazar, an analyst at The 451 Group.
Tape not slow when it matters
"Tape is not slow for things that are big," he said. For accessing a single large file such as a video, it's competitive with disk, he said.
Even the robots that find tapes in a library and place them in a drive are faster than they might seem. It typically takes about 30 to 40 seconds to retrieve a tape and get it running, according to IBM.
Enterprises that don't want to deal with tape themselves may now take advantage of it indirectly. Cloud service providers offer value by carrying out IT tasks at a larger scale than their customers can achieve, which gives them a cost advantage. When it comes to storage, the most economical way of doing that may be tape.