Wikipedia:Reference desk/Archives/Computing/2018 December 19

= December 19 =

"Please format SD card to FAT 32 before using..." ???
I am thinking of buying this dash cam. Tucked away on the page is the instruction: "Please format SD card to FAT 32 before using..." What does this mean and how do I do it? P.S. Any real advantage to buying a higher memory card for this--a 128 or 256 instead of a 64? Longer record time? Better reesolution video? Thanks--67.244.114.239 (talk) 06:41, 19 December 2018 (UTC)
 * Anything that stores data, needs a way to find this data back. There exist various variants of such systems, but FAT32 is one of the oldest and most common ones. The device itself can likely format the SD card, it will be in the instructions. Please be aware that when you format an SD card, you will loose any information on it. Newly bought SD cards often come preformatted as FAT32 (but not always).
 * The advantage of a bigger card is that it allows you to store more video. A dashcam will override itself once it fills up, but this size determines the age of the oldest video that it will be able to keep. For this setup, a 64GB SD card will hold about 3,5 hours of video and a 128GB about 7 hours. More important however with this particular camera is to pay attention to the speed of the card as they are actually 2 cameras which requires a high speed card. You need something that is 4K capable (often called a U3 card or a V30 or up). You will also want a proper brand, like Sandisk or Samsung. I personally use a "Samsung EVO Plus Micro SDXC 64 GB" for similar purposes and it has not failed me yet. —Th e DJ (talk • contribs) 08:32, 19 December 2018 (UTC)


 * If you are using Windows or Mac, the best program for reformatting an SD card is the official one from the SD Association. You can find it at [ https://www./downloads/formatter_4/ ]. --Guy Macon (talk) 10:55, 19 December 2018 (UTC)
 * Thanks all. Got it. And doubling the overwriting time for just a few bucks more feels prudent, so going for the 128.--67.244.114.239 (talk) 14:42, 19 December 2018 (UTC)
 * Something mangled the link. Here it is. --47.146.63.87 (talk) 21:48, 20 December 2018 (UTC)

Can my ISP personnel see which pages of a website i visited
I browse internet by first visiting a private IP address 172.16.0.1 and then logging in with username allotted to me by my ISP and a password.I want to know if my ISP can see exactly what pages of a website like http://en.wikipedia.org I have visited.Another thing is from ethernet port at the back of my CPU cabinet a CAT 5/CAT 6 cable comes out and goes to wifi router box at my building top with PoE power supply that is provided by my ISP.The box modem is of BATON make as far as I  know.Please help.103.24.110.150 (talk) 07:34, 19 December 2018 (UTC)
 * As long as you use HTTPS (secure web) version of websites, which most are these days, then your ISP can only see which domains (websites) you have visited, not the pages that you have visited (within it). —Th e DJ (talk • contribs) 08:14, 19 December 2018 (UTC)


 * It's a little-known fact, but thanks to the WMF it is possible in some cases for third parties to tell exactly what Wikipedia pages you read, even though you used https. The technical details are complex, but they are explained at Wikipedia:Village pump (policy)/RfC: Wikimedia referrer policy.


 * Consider the case where a Wikipedia user reads our page on Bomb-making instructions on the internet and then clicks on the link to Feinstein Amendment SP419 at Cornell university. A government agency then gets a court order giving them access to Cornell university's server logs (or someone simply hacks the server to get the logs). If we were a silent referrer (which the WMF rejected because it makes their requsts for donations less effective), the logs at cornell.edu would simply show that a particular person read https://www.law.cornell.edu/uscode/text/18/842, a perfectly innocent act. Because we send domain-only referrer information, the logs at cornell.edu will say that that person clicked on a link to the Feinstein Amendment SP419 page while reading Wikipedia, and a link search using the tool we helpfully provide will show that the only link to www.law.cornell.edu/uscode/text/18/842 on Wikipedia is from our Bomb-making instructions on the internet page. So, by sending referrer information, we just turned the government knowing that a particular user accessed the text of the Feinstein Amendment SP419 -- a perfectly innocent act in itself – to the government knowing that a particular user accessed the text of the Feinstein Amendment SP419 while reading the Wikipedia Bomb-making instructions on the internet page. Don't forget the couple who were questioned by the police after he did a google search on "backpacks" while she did a Google search on "pressure cookers" in another room... --Guy Macon (talk) 11:11, 19 December 2018 (UTC)
 * This is true of Web pages in general. Even if you visit an HTTPS site, by default, if your browser loads anything on other sites because the page tells it to (scripts, ads, etc.), it will send that site the referer, so now that site knows what you visited. And, if that site isn't HTTPS, anyone can read that going over the wire. Also modern browsers can, with prefetching, follow regular links without you even clicking on them. The Web was never designed to be a secure communications medium, and most Web browsers prioritize convenience and speed over security. If you really want to hide what you're visiting from a savvy attacker, you need to take a lot of precautions and have some computing know-how. Web searches will turn up various guides. --47.146.63.87 (talk) 21:40, 19 December 2018 (UTC)


 * Not true. In general (the user can override the default behavior), browsers only send referrer information if the website doing the referring tells them to.


 * Depending on how we configure Wikipedia if someone loads an external image or clicks on an external leak in our Bomb-making instructions on the internet page, the external site could get any of the following in the referrer:


 * en.wikipedia.org/wiki/Bomb-making_instructions_on_the_internet#[Section] (full URL)
 * en.wikipedia.org/wiki/Bomb-making_instructions_on_the_internet (domain plus page)
 * en.wikipedia.org (full domain)
 * wikipedia.org (partial domain)
 * No referrer information (silent referrer)


 * --Guy Macon (talk) 22:35, 19 December 2018 (UTC)
 * I admit I'm not an expert Web dev, but I was under the impression that browsers by default send a referer whenever they fetch a resource linked in a tag. I just checked this by loading nbc.com on stock Firefox, and every resource fetch passed a referer header. A site can instruct the browser to behave differently, either through a  tag or JavaScript, but this is deviating from the usual behavior (and of course requires browser support). Vis a vis the original question, you should assume your browser is sending referer headers, unless you've configured it not to. Of course, a bigger problem is JavaScript, which can do basically anything it wants. --47.146.63.87 (talk) 21:45, 20 December 2018 (UTC)


 * Another issue is that the "referer" might be acting secretly like part of the URL. Like, it at least used to be that if you went to a New York Times article directly they would give you some paywall crap, but if you copypasted the title into Google, ran the search, and clicked on the result they would display the article from the "same" URL.  Really, if the browsers were on our side they would have the referer in/near the address bar. Wnt (talk) 15:54, 21 December 2018 (UTC)