1854: Refresh Types

Explain xkcd: It's 'cause you're dumb.
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Refresh Types
The hardest refresh requires both a Mac keyboard and a Windows keyboard as a security measure, like how missile launch systems require two keys to be turned at once.
Title text: The hardest refresh requires both a Mac keyboard and a Windows keyboard as a security measure, like how missile launch systems require two keys to be turned at once.


Ambox notice.png This explanation may be incomplete or incorrect: This is chaos - multiple explanations should be merged and condensed. Do NOT delete this tag too soon.
If you can address this issue, please edit the page! Thanks.

This lists five different ways of refreshing a page. The first three are real ways to refresh a page. The last two are absurd options that would give an ordinary user the power to make large changes to the places where data is hosted and/or the internet as a whole.

The comic makes use of ambiguity of the term 'hard', which can mean both severity of an effect (on the scale of from resetting a part of a page, to the whole page, to its hosting provider and hosting infrastructure), and difficulty of triggering it (on the scale of having to input increasingly complex key combinations). (Think opposability of 'hard' to both 'soft' and 'easy'.)

The difference between the first two options: "soft refresh" and "normal refresh," is that Gmail (Google's email service) allows a user to "refresh" (update) their inbox with a "refresh" button accessed while at a web address, while a "normal refresh" involves pushing the browser's refresh button. The latter option is basically equivalent to closing the web page, then opening up a new window/tab in the browser and going to the same IP address; different websites would handle retaining a user's "logged in" status differently when this is done (often based on options the user selected), while any well-designed webpage would probably not log a user out for using a "soft refresh" on something like an e-mail inbox.

The third option, "hard refresh," refers to a keyboard shortcut to "refresh" their cached files associated with a webpage.

The fourth option, "harder refresh," exaggerates the trend to a silly level by suggesting that a web page user would be allowed to press an increasingly implausible combination of buttons on their keyboard (including the non-standard 'HYPER' key, a feature of the Space cadet keyboard) to reset the power at the entire data center where the web server for the page they are viewing is hosted.

The fifth option, "hardest refresh," implies that if the user activated it, somehow the entire internet would start over from ARPANET, a network funded by the United States Department of Defense that predates the World Wide Web and is important when studying the early history of the internet. (ARPA stands for Advanced Research Projects Agency.) Obviously, this is impossible.

The displayed keyboard shortcuts get longer for the "harder" options. Although probably intended for humor, this makes some sense, as options that are used less often might be assigned less convenient keyboard shortcuts, and the more drastic options (if they existed) might have very long keyboard shortcuts to prevent them from being activated by accident. The first few displayed shortcuts would actually work on many systems.

The title text envisions a security measure for the hypothetical godlike power of the "hardest refresh" that is like the security on missile launch systems. It references the comically long keyboard shortcut for listed for the "hardest refresh" that involves both the Windows key and the Command key (AKA Pretzel key, formerly Apple Key), which would not normally be located on the same keyboard.

Web page developers must keep in mind an ever-increasing number of shortcuts to force a page to refresh more or less thoroughly, i.e. causing cached local resources to be deleted and re-set.

The first option (soft refresh) uses the "refresh" button present as part of the Gmail interface to retrieve new messages from the server without reloading the whole webpage itself.

The second option (normal refresh) uses a browser refresh button which causes the entire page to reload. This will inherently retrieve new messages from the server, but also must do other tasks required to present the page for the first time.

Randall jokingly proposes a fictional "harder still" refresh option is a fictional refresh that sends a command to the Google Gmail server causing the entire data center where the server lives to power down and reboot everything, the Gmail equivalent of "turning it off and on again." This command would be extremely inconvenient for other users, who would be locked out of their emails until the datacenter reboots.

He goes on to propose a "hardest" refresh with a key combination resembling a 'cheat code' that causes the entire internet to be build anew from its origins in Arpanet.


Ambox notice.png This transcript is incomplete. Please help editing it! Thanks.
Refresh Type Example Shortcuts Effect
Soft Refresh Gmail REFRESH Button Requests update within Javascript
Normal Refresh F5, CTRL-R, ⌘-R Refreshes page
Hard Refresh CTRL-F5, CTRL-⇧, ⌘-⇧-R Refreshes page including cached files
Harder Refresh CTRL-⇧-HYPER-ESC-R-F5 Remotely cycles power to datacenter
Hardest Refresh CTRL- ⌘ÿ⇧#-R-F5-F-5-ESC-O-0-Ø-⏏-SCROLL LOCK Internet starts over from Arpanet

comment.png add a comment! ⋅ comment.png add a topic (use sparingly)! ⋅ Icons-mini-action refresh blue.gif refresh comments!


I tried the last one (omitting the keys that don't exist on my keyboard), and it runs Firefox as an administrator. 09:54, 5 June 2021 (UTC)

Similar to this comic. 14:55, 23 June 2017 (UTC)

Aren't you supposed to use Shift-F5 (at least in chrome) for a hard refresh - not Ctrl - F5. https://support.google.com/chrome/answer/157179?visit_id=1-636338263045956762-2405452703&hl=en&rd=2 (talk) (please sign your comments with ~~~~)

I believe that's correct. It is likely browser dependent. --Arccos (talk) 15:27, 23 June 2017 (UTC)
Erratum: The middle hard-refresh option is missing something - it lists only modifier keys. 15:32, 23 June 2017 (UTC)
It appears that the "hard refresh" option is a real option, but that the keyboard shortcuts in the comic may not be correct. The above user's linked material suggests that the keyboard shortcut for a hard refresh, labeled "Reload the current page, ignoring cached content", is, in Chrome, SHIFT-F5 or CTRL-Shift-R on Windows and APPLE-Shift-R on a keyboard for MacOS. This is in contrast to the comic, which currently lists CTRL-F5, CTRL-Up, and APPLE-UP-R as the shortcuts. 15:33, 23 June 2017 (UTC)
That's not an "UP," the symbol ⇧ represents the SHIFT key. Indeed it appears Randall omitted the 'R' inadvertently. JohnHawkinson (talk) 15:46, 23 June 2017 (UTC)
Randall says the keys are examples, meaning some may missing. But for me it looks like the most common shortcuts. Except the hard refresh by pressing CTRL+SHIFT, that's nonsense because a F5 or R should follow. I'm sure we will see a picture update soon. Stay tuned...--Dgbrt (talk) 15:44, 23 June 2017 (UTC)
Ctrl-F5 works across every browser. It does appear that Shift-F5 also works in Chrome. Trlkly (talk) 23:35, 23 June 2017 (UTC)

The missile launch keys can be totally identical for the two-man rule to work; the thing is not that they are interchangeable, but that the locks are too far apart for one person to operate both. Chrullrich (talk) 18:49, 23 June 2017 (UTC)

  • Big Bang refresh - restarts universe just to be sure there's nothing stuck in cache. (Of course in EMACS, that's just good old: C-x M-c M-bigbang).  :-) 20:41, 23 June 2017 (UTC)

It looks like the "harder refresh" shortcut also requires two keyboards to work, since the "hyper" key seems to only exist on the space-cadet keyboard, which does not have an F5 key. 19:12, 23 June 2017 (UTC)

What do we use when Skynet takes over? OldCorps (talk) 19:33, 23 June 2017 (UTC)

Gmail does not update instantaneously at all. I don't know how many times I've gotten a notification from my RSS feed, and then have to go to Gmail and press refresh. And that's not even counting external email. I frequently use the Gmail refresh button. Trlkly (talk) 23:30, 23 June 2017 (UTC)

That's weird, it definitely does for me. Sometimes it'll even update with the new unread emails before I get a notification that I got a new email. It updates faster than my work email. OldCorps (talk) 10:35, 24 June 2017 (UTC)

I also find it funny that this page uses an additional type of refresh: the "purge server cache" kind. Trlkly (talk) 23:30, 23 June 2017 (UTC)

Powercycling datacenter can't be that long downtime unless the servers starts checking discs. And sometimes remotely triggering soft reset of server would really help user of incorrectly written application - servers are generally configured in way which allows them to start all needed services automatically. -- Hkmaly (talk) 23:47, 23 June 2017 (UTC)

Dear Dgbrt, before deleting things and writing on topic you don't know about, please at least read this, this and this. (talk) (please sign your comments with ~~~~)

Hi IP, please sign your posts with ~~~~.
  • I have mentioned RFC 7234 meta-tags for suppressing caching.
  • "Difference between Ctrl+Refresh and Ctrl+Shift+Refresh". This an old QA from 2009 and still browser dependent. The HTTP-Response "304 Not Modified" isn't always reliable as I also have mentioned.
  • Your reboot statement doesn't belong to any cache issues. I will move it to the harder refresh section.
Please stop the edit war by just undoing content. I have rewritten something by using many existing phrases. Please read my edits first before becoming upset. And please follow a unique style according to the rest of the page.--Dgbrt (talk) 10:44, 24 June 2017 (UTC)
No war. I am clearly bad at explaining, so I'll not touch this explanation any more; you are free to fix it the way you want. But at least investigate the issue first, since your proposed sentence showed that you are not familiar with the issue. (talk) (please sign your comments with ~~~~)
Hi IP, PLEASE sign your posts with ~~~~.
I'm a web developer for more than 20 years including mobile devices as clients at a time the word smartphone wasn't invented. My 2ct.--Dgbrt (talk) 11:28, 25 June 2017 (UTC)
Status - currently eating popcorn waiting for the response to the haymaker Dgbrt just delivered. OldCorps (talk) 12:06, 25 June 2017 (UTC)
Off-topic transcript discussion

I want to say that ELinks (the text-based web browser that I, for some reason, have on my Ubuntu) displays this for the talk section. Isn't the transcript for text-based web browsers on comics where the official transcript fails? Also, I can't figure out how to put headers in. JacobDS65536 (talk) 01:33, 24 June 2017 (UTC)

I don't understand your problem. Are you talking about the talk section or the transcript? And what's wrong except the inverse text?--Dgbrt (talk) 10:44, 24 June 2017 (UTC)
The discussion area is enclosed in a div tag with some sort of background and text color settings. Your copy of ELinks is probably trying to emulate the background for you. -- 02:25, 25 June 2017 (UTC)

Seems like Randall keeps returning to missile launch topics after Trump... There have been quite a few since then. --Kynde (talk) 13:57, 24 June 2017 (UTC)

He mentioned the nuclear briefcase back during the Obama administration. 16:09, 24 June 2017 (UTC)

It would be nice if the transcript section here would use words to describe what the symbols are. Or possibly a separate table in the explanation section. Thanks 23:49, 24 June 2017 (UTC)

That's the reason why it's still incomplete. A real transcript doesn't need a table but a description what's in the image. This includes the full text but also a description of the content like pictures or symbols.--Dgbrt (talk) 11:28, 25 June 2017 (UTC)

Looks like Randall missed out a couple of intermediate refreshes:

  • Service refresh: restarts the HTTPD service on the web server, clearing out the services's cache
  • Warm server reboot: restarts the OS on the web server, clearing out the OS's cache

The cold server reboot usually clears out hardware caches, but the cache of battery-backed RAID controllers will survive a cold reboot. -- 10:34, 25 June 2017 (UTC)

Hey, you are on the server side. ;) --Dgbrt (talk) 11:28, 25 June 2017 (UTC)

So, what type of refresh are you all using today to make the next comic appear on xkcd? :-) 11:29, 26 June 2017 (UTC)

I think part of the joke is also that harder/hardest refers to the difficulty of using those shortcuts, instead of just the implications of the refresh command. -- 14:22, 26 June 2017 (UTC)

"And rebooting an actual physical server upon a web page request is not possible, unless there is a software or operating system bug that will cause exactly this." This is not exactly correct. It would be very possible to write functionality into a webpage (deliberately; not a bug) to reboot the server that it is running on or another server. This functionality would need server credentials to do so, provided by either the web coder or the user. This would be useful in e.g. a cloud infrastructure management dashboard. It would be a very bad idea to a public facing webpage without credentials required to prove that the user is authorized to perform reboots of the given servers. (talk) (please sign your comments with ~~~~)

Maybe it should read "common web pages" or something similar, because you're right. There are administrative web pages like Webmin capable of doing exactly this.--Dgbrt (talk) 17:02, 26 June 2017 (UTC)

Somehow, somewhere, I was expecting a reference to the Konami code for the Hardest Refresh. :) (i.e. either by Randall or somewhere here) NiceGuy1 (talk) 04:52, 27 June 2017 (UTC)