explain xkcd - User contributions [en]

1854: Refresh Types

2017-06-26T06:45:15Z

Diz: /* Transcript */

{{comic
| number = 1854
| date = June 23, 2017
| title = Refresh Types
| image = refresh_types.png
| titletext = 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.
}}

==Explanation==
In this comic [[Randall]] presents five different levels of refresh operations for web applications. The first three (''soft refresh'', ''normal refresh'', and ''hard refresh'') are common operations to keep the content in the browser retrieved from the server up to date. The other two (''harder refresh'' and ''hardest refresh'') are fictional operations to perform ''refresh'' operations on remote resources. The terms are probably adopted from {{w|Reboot (computing)|soft}} and {{w|Hardware reset|hard reset}} operations used to restart broken computers or e.g. smartphones.

=== Soft refresh ===
''Soft refresh'' refers to an operation in a web page that requests new information without reloading the entire page. The given example, {{w|Gmail}}, includes a feature that allows users to poll new emails and show it in the inbox interface. It is a command using {{w|JavaScript}} and {{w|Ajax (programming)|Ajax}} to load new contents from the server in the background and only update necessary components of the page. Since modern web applications do this also automatically in short time intervals those buttons are mostly unnecessary. In Gmail a user will see a new message instantly.

=== Normal refresh ===
The ''normal refresh'' is a browser operation that reloads the complete web page, text and other content that has changed since the original load will be updated. The operation can be triggered by refresh buttons in browsers, though it also can be requested using the common keyboard commands as listed by Randall. Many pages -- like the main page at xkcd.com -- don't have a refresh button. If the page has been opened before a new comic release, pressing F5 afterwards causes reload and the new comic is shown.

=== Hard refresh ===
What Randall calls ''hard refresh'' is a less common browser operation forcing the browser to re-download every part of the webpage, ignoring any cached content. Caching is a common way of decreasing webpage load times. Browsers save resources such as images or {{w|Cascading Style Sheets|CSS stylesheets}} on the first visit on a webpage and use the local copy on subsequent visits. It allows them to decrease amount of transfer needed to show the webpage, but prevents showing changes made to the resources (for example a web developer changing the stylesheet). In those cases the ''hard refresh'' ensures that each part of the website is downloaded in its newest form.

If there is a {{w|Proxy server|Web-Proxy}} or a Cloud-Cache (like used for this wiki) in between the browser and the Web-Server this type of refreshing may not work. In this case, unless a purge link is available, the user has to wait until the cache entry is expired and a new request to the web server is done. A Web-developer may try to avoid this behaviour by including special meta-tags in the HTML header to suppress caching, but not all proxies or clouds follow these instructions.

=== Harder refresh ===
''Harder refresh'' is a joke that extends the existing naming scheme. The joke is that if a ''hard refresh'' resets the browser display and cache, a ''harder refresh'' should reset the source of the data by cycling power in the data center. Assuming no damage was done, this would reset the memory on the server, erasing any information that had not been written to disk, and setting the server to the state it was in at launch. This would cause considerable downtime, and would be unlikely to help the user at all.

In {{w|Orchestration (computing)|orchestrated}} environment it may indirectly cause some virtual machines in the {{w|Cloud computing|cloud}} to be rebooted and assigned to an other web server needing more workload. But a growing workload is caused by hundreds or thousands additional requests and not just a single key combination from one browser. 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.

The ''harder refresh'' uses six keys, including the non-standard '[https://askubuntu.com/questions/19558/what-are-the-meta-super-and-hyper-keys HYPER]' key, a feature of the {{w|Space cadet keyboard}}.

=== Hardest refresh ===
The fifth option, ''hardest refresh'', moves beyond resetting the source of the data and resets the entire internet back to {{w|ARPANET}}, an early military network which was a forerunner to the modern internet. The implications of this are not made clear, but it should be noted that it wouldn't help to fix any problems a user is experiencing in-browser, as {{w|HTTP}}, the protocol by which web pages are sent, was not developed until late 1990, the year ARPANET was decommissioned.

The ''hardest refresh'' shortcut uses fifteen keys, including non-standard ones such as Ø and ⏏. (The former is a key found on Norwegian and Danish keyboards, the latter is the "eject" key found on Mac keyboards and some laptops.) The shortcut makes amusing comparisons about a shortcut that includes not only the F5 function key, but also the keys for the letter "F" and the digit "5", as well as the similarity in appearance between O, 0, and Ø.

The title text suggests that the inclusion of both the {{w|Windows key}} and {{w|Command key}} in the ''hardest refresh'' shortcut is a security measure akin to the {{w|Two-man rule}}, as it would require two keyboards to enter.

==Transcript==
{{incomplete transcript|Do NOT delete this tag too soon.}}

:[A table with three columns is shown. The header is:]
:Refresh Type; Example Shortcuts; Effect

:[First row:]
:Soft Refresh
:[The word refresh has a border to mimic a button:]
:Gmail <span style="border: 1px solid black">REFRESH</span> Button
:Requests update within JavaScript

:[Second row:]
:Normal Refresh
:[Two PC shortcuts and the Apple command key followed by an R:]
:F5, CTRL-R, ⌘R
:Refreshes page

:[Third row:]
:Hard Refresh
:[One PC shortcut, the combination Control plus Shift, and the Apple command key followed by Shift and R:]
:CTRL-F5, CTRL-⇧, ⌘⇧R
:Refreshes page including cached files

:[Fourth row:]
:Harder Refresh
:[One single combination using Control plus Shift plus Hyper plus Escape plus R plus F5:]
:CTRL-⇧-HYPER-ESC-R-F5
:Remotely cycles power to datacenter

:[Fifth row:]
:Hardest Refresh
:[One single combination using Control plus the Apple command key plus the Windows key plus Shift plus the hash key plus R plus F5 plus F plus 5 plus Escape plus the letter O plus a slashed zero plus a slashed letter O plus an eject sign plus Scroll Lock:]
:CTRL-⌘<span title="Windows key logo">⊞</span>⇧#-R-F5-F-5-ESC-O-0-Ø-⏏-SCROLL LOCK
:Internet starts over from ARPANET

==Trivia==

* One of the shortcuts listed for Hard Refresh, “CTRL-⇧”, is incorrect – it should be “CTRL-⇧-R”.

{{comic discussion}}

[[Category:Computers]]
[[Category:Internet]]

Talk:1850: Air Force Museum

2017-06-16T06:10:50Z

Diz:

Might the title text be referring to the concepts of [https://en.wikipedia.org/wiki/Alternative_pleading alternative pleading] or [https://en.wikipedia.org/wiki/Kettle_logic kettle logic]? [[User:Spagovir|Spagovir]] ([[User talk:Spagovir|talk]]) 19:34, 15 June 2017 (UTC)
:I could concur with either / both, but more Alternative Pleading than Kettle Logic. Mostly since it seems like the former uses hypothetical language like "If" and "in which case" - which this does - and the latter seems to be more about solid but contradictory statements - "I enjoyed Dover Air Force Base. I've never been to Denver." Also, it seems like Kettle Logic statements should have the same goal, "I'm innocent because of these conflicing reasons.", in this case maybe it's not a problem because it's a museum and it's not a problem because he hasn't been to Denver. But he didn't say that. :) [[User:NiceGuy1|NiceGuy1]] ([[User talk:NiceGuy1|talk]]) 04:21, 16 June 2017 (UTC)

And I hear if you have a basic understanding of computer systems and know a reservist Colonel, you can hack into the flight schedule, reserve two fighters fully loaded down with as much ordnance as they can carry, and go on a rescue mission to save your father who was shot down in disputed airspace. [[User:OldCorps|OldCorps]] ([[User talk:OldCorps|talk]]) 18:31, 14 June 2017 (UTC)
:What movie is that? (... at least, I ''hope'' it is a movie.) [[User:Chrullrich|Chrullrich]] ([[User talk:Chrullrich|talk]]) 18:43, 14 June 2017 (UTC)
::[http://www.imdb.com/title/tt0091278/ Iron Eagle]. [[User:OldCorps|OldCorps]] ([[User talk:OldCorps|talk]]) 19:23, 14 June 2017 (UTC)
:::At least it was easy to get to. Better than the space museum I went to last time, had to actually go into space for that one! And the only thing on exhibit was this strange communications satellite that was armed with nuclear missiles for some weird reason. ([http://www.imdb.com/title/tt0186566/ Space Cowboys], just saw it for the first time last week, LOL!) [[User:NiceGuy1|NiceGuy1]] ([[User talk:NiceGuy1|talk]]) 03:52, 16 June 2017 (UTC)

The mention of "planes from different eras" alludes to the fact that military aircraft are often still in use after a much longer time than they were originally designed for. Examples of this are the US Air Force's B-52 bomber, first introduced in 1955 (62 years before the publication of this comic) and the C-160 Transall, which has been in service in, e.g., the German Luftwaffe, since 1967 (50 years before). Additionally, aircraft museums typically house military aircraft from previous eras, such as from WWII and the Cold War, to show the evolution in aircraft design and to showcase technological advances.

It struck me as more, if not entirely, the latter. I didn't perceive any allusion to the fact that "military aircraft are often still in use after a much longer time than they were originally designed for" [[Special:Contributions/162.158.74.51|162.158.74.51]] 05:13, 15 June 2017 (UTC)
:I've removed the C-160 Transall because the German Luftwaffe doesn't belong to any US Air Base. But have you ever seen a B-52 bomber? It's a really historic plane.--[[User:Dgbrt|Dgbrt]] ([[User talk:Dgbrt|talk]]) 12:31, 15 June 2017 (UTC)
:I find the fact that museums would house aircraft from different eras would be WHY he thought it was a museum, that the joke is that the Air Force uses such old hardware that a base can be mistaken for a museum. Worded like it is in the explanation, "Additionally, museums blah blah blah" is a weird way to word something that's a basic part of the joke. The joke is almost entirely the former, that the military keeps hardware in use far longer than is wise. [[User:NiceGuy1|NiceGuy1]] ([[User talk:NiceGuy1|talk]]) 03:52, 16 June 2017 (UTC)

I have seen older aircraft on static display at Oceana and Willow Grove Naval Air Stations. I wouldn't be surprised if the same was also true of some Air Force Bases. [[User:BradleyRoss|BradleyRoss]] ([[User talk:BradleyRoss|talk]]) 03:09, 16 June 2017 (UTC)

;Implication of pursuit?
The implication is that there was no museum to begin with and Cueball went to observe the actual air force base and '''''is now being pursued by the military'''''.

I don't think there's anything to credibly suggest Cueball is being pursued. Hearing helicopters implies they are close enough to perceive a military operation of some sort, but it could easily be launching aircraft departing to another destination as it might be pursuit of Cueball. Is there anything to justify the last 7 words? [[User:JohnHawkinson|JohnHawkinson]] ([[User talk:JohnHawkinson|talk]]) 01:54, 15 June 2017 (UTC)
:Realistically, they would be pursued by MPs and probably local police in vehicles, not helicopters. But if Cueball was (intentionally or accidentally) able to get on a base and into a hangar where they were loading ordnance onto jets, they might very well include air units in the search for him. The bigger question is where was Megan while Cueball was inside, seeing as she was close enough to accompany him in the not-so-tactical escape. [[User:OldCorps|OldCorps]] ([[User talk:OldCorps|talk]]) 11:48, 15 June 2017 (UTC)
::I think you mean "ordnance," not "ordinance." The two words mean completely different things. --[[Special:Contributions/172.68.58.101|172.68.58.101]] 12:31, 15 June 2017 (UTC)
:::Yup, thanks. I'm writing these half asleep, appreciate the sanity check. Corrections made.[[User:OldCorps|OldCorps]] ([[User talk:OldCorps|talk]]) 13:48, 15 June 2017 (UTC)
::He's not running and the visit of air base probably happened some time before their meeting. Meaning if they are pursuing him NOW, it shows they are doing it very ineffectively, which on the other hand matches the fact he was able to get inside air base and out without any problems despite, presumably, wandering around without any attempt to hide as you would do in museum. -- [[User:Hkmaly|Hkmaly]] ([[User talk:Hkmaly|talk]]) 00:53, 16 June 2017 (UTC)
:::I agree with Hkmaly, I understood this as being some time later (later that evening, maybe even the next morning), that he's relating his experience to Megan while chatting, not that he's currently leaving. Also that his uncertainty about what he actually did would imply that there was no actual pursuit at the time, that said helicopters may have been looking for him, but he just happened to leave before anybody found him. And Megan is reassuring him that if it really was a base that they'd be looking for him even now. After all, if this was RIGHT after, Megan wouldn't ask the generic question, but more specifically "How was the museum?", and he wouldn't have to start by saying what he did. [[User:NiceGuy1|NiceGuy1]] ([[User talk:NiceGuy1|talk]]) 03:52, 16 June 2017 (UTC)
:I took the helicopter line as implied pursuit / searching. I might have been influenced by the fact that I've been playing Grand Theft Auto 5 lately, and EXACTLY THIS happening when you get more than a little Wanted, helicopters looking for you. LOL! And that if you visit their mixed military base you get more than enough Wanted to get said helicopters looking for you. :)

:Aaaaand I just realized I can take Megan's line two ways. "Don't worry, if it was a base you'd hear helicopters" (my initial take) and that she actually hears (or worries that she hears) helicopters searching for him. :) [[User:NiceGuy1|NiceGuy1]] ([[User talk:NiceGuy1|talk]]) 03:52, 16 June 2017 (UTC)
:My take was, that the fact that Missiles were loaded during his visit might have been in preparation for a strike, so cueball's hope is not him not being pursued, but not having witnessed the first moments of a war. The helicopters would then be a reference to Radar in Robert Altman's "M*A*S*H". The title text seems to make the pursuit interpretation more plausible, though. [[User:Diz|Diz]] ([[User talk:Diz|talk]]) 06:08, 16 June 2017 (UTC)

Talk:1850: Air Force Museum

2017-06-16T06:08:00Z

Diz:

Might the title text be referring to the concepts of [https://en.wikipedia.org/wiki/Alternative_pleading alternative pleading] or [https://en.wikipedia.org/wiki/Kettle_logic kettle logic]? [[User:Spagovir|Spagovir]] ([[User talk:Spagovir|talk]]) 19:34, 15 June 2017 (UTC)
:I could concur with either / both, but more Alternative Pleading than Kettle Logic. Mostly since it seems like the former uses hypothetical language like "If" and "in which case" - which this does - and the latter seems to be more about solid but contradictory statements - "I enjoyed Dover Air Force Base. I've never been to Denver." Also, it seems like Kettle Logic statements should have the same goal, "I'm innocent because of these conflicing reasons.", in this case maybe it's not a problem because it's a museum and it's not a problem because he hasn't been to Denver. But he didn't say that. :) [[User:NiceGuy1|NiceGuy1]] ([[User talk:NiceGuy1|talk]]) 04:21, 16 June 2017 (UTC)

And I hear if you have a basic understanding of computer systems and know a reservist Colonel, you can hack into the flight schedule, reserve two fighters fully loaded down with as much ordnance as they can carry, and go on a rescue mission to save your father who was shot down in disputed airspace. [[User:OldCorps|OldCorps]] ([[User talk:OldCorps|talk]]) 18:31, 14 June 2017 (UTC)
:What movie is that? (... at least, I ''hope'' it is a movie.) [[User:Chrullrich|Chrullrich]] ([[User talk:Chrullrich|talk]]) 18:43, 14 June 2017 (UTC)
::[http://www.imdb.com/title/tt0091278/ Iron Eagle]. [[User:OldCorps|OldCorps]] ([[User talk:OldCorps|talk]]) 19:23, 14 June 2017 (UTC)
:::At least it was easy to get to. Better than the space museum I went to last time, had to actually go into space for that one! And the only thing on exhibit was this strange communications satellite that was armed with nuclear missiles for some weird reason. ([http://www.imdb.com/title/tt0186566/ Space Cowboys], just saw it for the first time last week, LOL!) [[User:NiceGuy1|NiceGuy1]] ([[User talk:NiceGuy1|talk]]) 03:52, 16 June 2017 (UTC)

The mention of "planes from different eras" alludes to the fact that military aircraft are often still in use after a much longer time than they were originally designed for. Examples of this are the US Air Force's B-52 bomber, first introduced in 1955 (62 years before the publication of this comic) and the C-160 Transall, which has been in service in, e.g., the German Luftwaffe, since 1967 (50 years before). Additionally, aircraft museums typically house military aircraft from previous eras, such as from WWII and the Cold War, to show the evolution in aircraft design and to showcase technological advances.

It struck me as more, if not entirely, the latter. I didn't perceive any allusion to the fact that "military aircraft are often still in use after a much longer time than they were originally designed for" [[Special:Contributions/162.158.74.51|162.158.74.51]] 05:13, 15 June 2017 (UTC)
:I've removed the C-160 Transall because the German Luftwaffe doesn't belong to any US Air Base. But have you ever seen a B-52 bomber? It's a really historic plane.--[[User:Dgbrt|Dgbrt]] ([[User talk:Dgbrt|talk]]) 12:31, 15 June 2017 (UTC)
:I find the fact that museums would house aircraft from different eras would be WHY he thought it was a museum, that the joke is that the Air Force uses such old hardware that a base can be mistaken for a museum. Worded like it is in the explanation, "Additionally, museums blah blah blah" is a weird way to word something that's a basic part of the joke. The joke is almost entirely the former, that the military keeps hardware in use far longer than is wise. [[User:NiceGuy1|NiceGuy1]] ([[User talk:NiceGuy1|talk]]) 03:52, 16 June 2017 (UTC)

I have seen older aircraft on static display at Oceana and Willow Grove Naval Air Stations. I wouldn't be surprised if the same was also true of some Air Force Bases. [[User:BradleyRoss|BradleyRoss]] ([[User talk:BradleyRoss|talk]]) 03:09, 16 June 2017 (UTC)

;Implication of pursuit?
The implication is that there was no museum to begin with and Cueball went to observe the actual air force base and '''''is now being pursued by the military'''''.

I don't think there's anything to credibly suggest Cueball is being pursued. Hearing helicopters implies they are close enough to perceive a military operation of some sort, but it could easily be launching aircraft departing to another destination as it might be pursuit of Cueball. Is there anything to justify the last 7 words? [[User:JohnHawkinson|JohnHawkinson]] ([[User talk:JohnHawkinson|talk]]) 01:54, 15 June 2017 (UTC)
:Realistically, they would be pursued by MPs and probably local police in vehicles, not helicopters. But if Cueball was (intentionally or accidentally) able to get on a base and into a hangar where they were loading ordnance onto jets, they might very well include air units in the search for him. The bigger question is where was Megan while Cueball was inside, seeing as she was close enough to accompany him in the not-so-tactical escape. [[User:OldCorps|OldCorps]] ([[User talk:OldCorps|talk]]) 11:48, 15 June 2017 (UTC)
::I think you mean "ordnance," not "ordinance." The two words mean completely different things. --[[Special:Contributions/172.68.58.101|172.68.58.101]] 12:31, 15 June 2017 (UTC)
:::Yup, thanks. I'm writing these half asleep, appreciate the sanity check. Corrections made.[[User:OldCorps|OldCorps]] ([[User talk:OldCorps|talk]]) 13:48, 15 June 2017 (UTC)
::He's not running and the visit of air base probably happened some time before their meeting. Meaning if they are pursuing him NOW, it shows they are doing it very ineffectively, which on the other hand matches the fact he was able to get inside air base and out without any problems despite, presumably, wandering around without any attempt to hide as you would do in museum. -- [[User:Hkmaly|Hkmaly]] ([[User talk:Hkmaly|talk]]) 00:53, 16 June 2017 (UTC)
:::I agree with Hkmaly, I understood this as being some time later (later that evening, maybe even the next morning), that he's relating his experience to Megan while chatting, not that he's currently leaving. Also that his uncertainty about what he actually did would imply that there was no actual pursuit at the time, that said helicopters may have been looking for him, but he just happened to leave before anybody found him. And Megan is reassuring him that if it really was a base that they'd be looking for him even now. After all, if this was RIGHT after, Megan wouldn't ask the generic question, but more specifically "How was the museum?", and he wouldn't have to start by saying what he did. [[User:NiceGuy1|NiceGuy1]] ([[User talk:NiceGuy1|talk]]) 03:52, 16 June 2017 (UTC)
:I took the helicopter line as implied pursuit / searching. I might have been influenced by the fact that I've been playing Grand Theft Auto 5 lately, and EXACTLY THIS happening when you get more than a little Wanted, helicopters looking for you. LOL! And that if you visit their mixed military base you get more than enough Wanted to get said helicopters looking for you. :)

:Aaaaand I just realized I can take Megan's line two ways. "Don't worry, if it was a base you'd hear helicopters" (my initial take) and that she actually hears (or worries that she hears) helicopters searching for him. :) [[User:NiceGuy1|NiceGuy1]] ([[User talk:NiceGuy1|talk]]) 03:52, 16 June 2017 (UTC)
:My take was, that the fact that Missiles were loaded during his visit might have been in preparation for a strike, so cueball's hope is not him not being pursued, but not having witnessed the first moments of a war. The helicopters would then be a reference to Radar in Robert Altman's "M*A*S*H". [[User:Diz|Diz]] ([[User talk:Diz|talk]]) 06:08, 16 June 2017 (UTC)