'Sneakernet' is a colloquial term for moving data by walking back and forth with a removable digital medium such as a floppy disk or tape in your hand.

In 'IBM's 360 and Early 370 Systems', page 533, I came across this interesting quote:

It was over a year after he moved to Boulder before Winger could spare resources for more than preliminary studies. By then his observations of tape library operations at several installations had convinced him that a lot of machine time and labor could be saved if the process could be automated and placed under computer control. At the McDonnell Douglas Corporation in St. Louis, for example, he had watched "boys and girls in tennis shoes, running back and forth between the machine room and the tape library, carrying as many as eight to ten reels on one arm." Tapes could easily be misplaced in the library or on the machine floor, thus wasting expensive time and delaying the completion of critical jobs.

My experience with sneakernetting was in the eighties and nineties with floppy disks, where it was just something everyone did from time to time. It hadn't occurred to me that in the big old mainframe systems, it might be a full-time job, yet that seems to be what the above description is suggesting.

Am I understanding the description correctly? In the old mainframe systems, were people actually employed full-time, specifically to carry tapes and disk packs back and forth?

  • 3
    Junior/Trainee Computer operators would start in the tape room / print room etc. Some sites would rotate them between various functions. Other sites may have employed people just in the Tape rooms. So basically yes. Mar 23, 2019 at 4:19
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    The way I understand "sneakernet" is that it is an "alternative" to a "real" network (hence "-net"): You transfer data between computers by carrying them in person on some kind of medium, instead of sending it over the network. So carrying tapes to and from the tape library is not an instance of sneakernet, but part of the normal operation of a mainframe, and it's an optimization of this part of the operation that the quote is about. So I would question the assumption that "sneakernetting" was a full time job, at any time.
    – dirkt
    Mar 23, 2019 at 10:40
  • @dirkt Well, while I've never seen a tape library in operation, I've seen ethernet used to connect computers to other devices like printers and CD-ROM drives (in the days when the latter were expensive), and this did not result in the ethernet being called not a real network.
    – rwallace
    Mar 23, 2019 at 11:12
  • 1
    @rwallace The point wasn't that a network is only called a "real" network when it connects two computers. The point was that "sneakernet" is the replacement for transferring data between computers (it has to be computers to read and load the medium the person carries) not over the network (when it would be too slow, or for other reasons), but by storage medium. Which can also be a lorry of tapes or CDs. The "tape library" of a mainframe system is just where all the tapes are stored.
    – dirkt
    Mar 23, 2019 at 20:14
  • 2
    We still use sneakernet (we call it walker net) to transfer code or binaries between physically disconnected networks. I know of many small offices where networking knowledge is near zero and a sneakernet memory stick is used to transfer data between PCs.
    – cup
    Jan 15, 2023 at 9:36

3 Answers 3


That quote sounds quite chaotic. My experience about tapes (and disks) moved to/from storage in /370 installations is of orderly carts made to hold up to 50 tapes or 6-8 disk stacks, fine labelled and handled on a fixed schedule (twice daily, some places more often) by a dedicated service. No running with tapes up the arms or alike. Everything planned ahead - after all, that's what IT is about, not only in Germany, isn't it?

The service was much like internal (and incoming/outgoing) mail is handled in big companies. Except the routes/destinations were few. Usually it was the archive guys that pushed the carts as part of their job. Some walking exercise in addition to place the right numbered tape into the right shelf location according to some printout from the archive system - or fetching it from there.

So the job description was more of a computer archive handler than a sneakernet delivery boy.

Transfers between locations (of large companies) were usually done by the internal mail service. So their description is the one of a mail handler.

  • "Except the routes/destinations where a few." That doesn't make sense. Mar 25, 2019 at 1:17
  • @Acccumulation mail goes from any office to any office, while tapes where usually only send between computer installations - wasn't it?
    – Raffzahn
    Mar 25, 2019 at 1:56
  • So do you mean "Except there were only a few routes/destinations"? Mar 25, 2019 at 2:30
  • I'll just leave this here: tools.ietf.org/html/rfc1149
    – JeremyP
    Mar 28, 2019 at 13:01
  • In some places, IT is about end users adding Tasks and Incidents to a ticket system, and then IT processing them in priority order.
    – RonJohn
    Jan 15, 2023 at 11:52

In the company I worked for, there certainly weren't people "running around" with tapes etc. The "tape library" was a whole department, and the physical storage occupied almost a complete floor of the computer building.

The size of the library was well over 10,000 tape reels - not all "active" or regularly used, but much of it was data from engineering tests, some of it dating back several decades.

If you wanted to run a "tape job" that wasn't part of the regular schedule, you filled in the paperwork specifying exactly which reel numbers you needed - and if you got that wrong, the operators didn't "run around" to fix the problem, your job was simply aborted. If you screwed up the paperwork more than once, your manager would get an earful of abuse from the tape library management, for wasting everyone's time!

The tape librarians were not just there to do the "fetching and carrying" - they also had the responsibility for making backup copies, "refreshing" old archival data by periodically copying it onto new tapes, etc.


The term "sneakernet" is generally used to refer to the pattern of writing of information onto a removable storage medium by one computer, which is expected to also retain the information, transporting the storage medium to some other computer, making a copy of the information to a fixed storage medium in the second computer, and afterward having no further use for the copy on the removable medium.

In the scenario described by the OP, by contrast, it more likely that the information was written to the removable storage media for the purpose of avoiding the need to keep the information on more expensive fixed storage.

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