I assume that the term download was coined first and then similar terms as upload, downstream, upstream followed.

But why are servers up, while clients are down? Who coined (one of) these terms and when?

  • 9
    The convention is reversed for PLCs, where "download" is PC -> PLC and "upload" is PLC -> PC.
    – shoover
    Nov 9, 2019 at 22:52
  • 25
    The situation isn't reversed, it's just the machines have different positions in the 'stream'. Sending info to a connected subordinate device is a download because you are now the server, therefore upstream of that device.
    – Tetsujin
    Nov 10, 2019 at 9:37
  • 4
    I guess, the confusion comes from the fact that a user clicking button "download" expects a file (or information) to arrive from elsewhere to their computer/device, not to be sent out. But as was pointed out by @Tetsujin, it depends on the roles of systems in the transfer process.
    – VL-80
    Nov 10, 2019 at 16:15
  • 4
    Just like in the song: 'the Bronx is up, the Battery's down'.
    – user207421
    Nov 11, 2019 at 5:49
  • 5
    Same question from 2017 over on EL&U
    – smci
    Nov 11, 2019 at 22:56

4 Answers 4


Water flows downhill. (I'm aware this is not new information ;)
The supply is at the top & the receiver [eventually the sea] is at the bottom.

Downstream is further from the supply, being supplied from upstream.
Upstream & downstream, or upriver/downriver are expressions probably as old as language itself to determine a direction in a stream/river without any need of compass direction.

Radio & television were one-way communications - so the broadcaster, ie the 'server', is upstream & all the listeners/viewers downstream of that.

Upload/Download simply follows that convention.

Addition after hitting HNQ list & attracting more attention than originally envisaged…

I think once you have the basic 'water-flow' analogy, from before we even knew what electricity was, let alone broadcasting or the modern cloud/server/CDN/client etc etc, everything else just follows logically. It only needed one person to make the initial connection - & we may never know who it was - back in the early days of radio, or even if radio was first to use it… it might be harder than who coined the term "broadcast" - https://en.wikipedia.org/wiki/History_of_broadcasting - which does have an answer.

  • 2
    I guess this also came up because of the positioning of clients and servers in charts and presentations, where the servers were typically positioned at the top of the chart and the clients at the bottom. Because there are often more clients than servers, this made up a shapely tree structure. (Side fact: the term "cloud" also came up because the ominous server structure was illustrated by a cloud symbol in presentations to the management by engineers who wanted to keep things simple.)
    – oddparity
    Nov 12, 2019 at 9:01
  • There's also the aspect that in asynchronous communication technologies, such as ADSL and traditional modems, there is a ratio of downstream to upstream speed, just like trying to swim in a river where there's a tradeoff of effort of upstream to downstream. Nov 12, 2019 at 11:13
  • 3
    Oddly enough, we now use the term "cloud" for remote storage and processing systems... So we _down_load from the cloud, which makes sense, as clouds are typically above us. Obviously this isn't the origin of the term, but it's interesting how it fits in.
    – Baldrickk
    Nov 12, 2019 at 12:02
  • I think once you have the basic 'water-flow' analogy, from before we even knew what electricity was, let alone broadcasting or the modern cloud/server/CDN/client etc etc, everything else just follows logically. It only needed one person to make the initial connection - & we may never know who it was, back in the early days of radio, or even if radio was first to use it… it might be harder than who coined the term "broadcast" - en.wikipedia.org/wiki/History_of_broadcasting - which does have an answer.
    – Tetsujin
    Nov 12, 2019 at 16:34
  • 3
    This explanation is probably right for "downstream" and "upstream", from the analogy of water (data) flowing in a particular direction. However these terms are unrelated "download" and "upload", which have a different etymology as described in the answer by @DavePhD Nov 12, 2019 at 21:44

Initially, "download" and "upload" were used in aviation, especially by the US military. "Download" meant to remove items such as weapons from the aircraft, while "upload" meant to load items onto the aircraft.

For example, the August 1963 Aerospace Maintenance Safety (a publication of the US Air Force) says at page 18:

Failure to follow written procedures and download the missiles...

(meaning failure to remove the missiles from the aircraft)

Then, within the US Air Force, the concept was extended to computers.


ADC provided a three-man team, which visited the bases some 30 days prior to conversion and conducted a full-scale download of the 305 and upload of the 1050, requiring 10 to 15 days.

where "305" means IBM 305 RAMAC and "1050" means the UNIVAC 1050

The terms "downstream" and "upstream" were used independent of "download" and "upload" in the early days of cable television.

For example see the November 1971 Interactive Television, Prospects for Two-Way Services on Cable which has a nice explanation:

One-way cable television systems distribute signals from a central point -- the headend -- to many subscribers over a party-line or "tree "network (Figure la). Everyone receives the same "downstream" signals on his cable at the same time.
Two-way cable television services require information flow "upstream" from the subscriber to the headend or among subscribers themselves.

  • 1
    This is the most likely explanation for "download", from the sense of moving something from from A to B or removing something from a place. Just as in the military sense of material being downloaded off a transport (or uploaded on to it) we get the computing sense of a download of data from a computer or an upload of data to a computer. Despite the similar prefixes these terms are unrelated to "downstream" and "upstream", which come from the analogy of water (or data) flowing in a particular direction. Nov 12, 2019 at 21:41

These terms are leftovers from the times of elementary client/server computing. You and many others were using a PC-like-thing, at best, and they communicated with a big/huge server somewhere, often a mainframe at first. The server was assumed to be 'up', as in 'uphill' or more exactly 'above you'. The server had almost total control of what was happening in the application, so it definitely had a superior status, hence the 'up'.

Plus you know, we really needed a convention used by everyone talking about this stuff, much like which side of the road to drive on.


Download means to transfer a file (or data) to your computer from somewhere "out there". The internet is often represented as a cloud, and clouds are in the sky. So transferring data to yourself from the cloud is to bring it down to where you are.

  • 57
    The up/down terminology predates the "cloud" metaphor by decades. It may even predate the Internet, with stuff like dial-up modem or hardwired serial terminal upload/download (e.g. xmodem). This answer might be useful as a mnemonic / memory aid for modern users but it's definitely nothing to do with the origin of the terms. Nov 10, 2019 at 2:33
  • 4
    @PeterCordes PSTN has been drawn as a cloud since X.25 days, at least. I agree, this etymology is still a bit dubious though.
    – richardb
    Nov 10, 2019 at 9:39
  • 4
    @RonJohn: When I said "predates the Internet", I was including its origins in ARPANET back in the 1960s. Not just the 80s / 90s when people in general started to hear about the Internet after BBSes were a known thing. I was forgetting that early computer networks weren't called Internet until later. Nov 11, 2019 at 12:36
  • 2
    @RonJohn: Right, agreed. And "the cloud" as a term came much later than the Internet for many people. In early days, you still had all your data on your desktop. I was just saying that we both agree up/down terminology goes back a long way, like early 80s at least, probably much earlier. Nov 11, 2019 at 14:02
  • 11
    In ~1983 a coworker expressed puzzlement that transfer from the big computer downstairs to his desk computer upstairs was called ‘downloading’! Nov 12, 2019 at 2:59

Your Answer

By clicking “Post Your Answer”, you agree to our terms of service, privacy policy and cookie policy

Not the answer you're looking for? Browse other questions tagged or ask your own question.