It's truly amazing how someone can now put together a brand new computer for less than $100 with a bit of effort. I have the Raspberry Pi 2 and it's quite impressive, especially when running on an ARMv7-compatible Linux build.
Add a dirt-cheap screen to the Raspberry Pi B+
21–30 of 66 posts
Re: Add a dirt-cheap screen to the Raspberry Pi B+
#22Maybe they can tackle the long-lived, widely-experienced SD card corruption issues of the RPi in the next version instead of adding a bunch more pins and an extra core. Meanwhile the competition even has eMMC in the same price range.
This comes up with every Pi post on HN for some reason, but if you're getting SD card corruption you either have a bad card (check the known good cards: http://elinux.org/RPi_SD_cards ) or are not shutting the Pi down correctly. You absolutely cannot just pull the power cord out while booted up because the SD card might be in the process of writing and you'll easily corrupt it. Make sure you always run 'sudo shutdown…
This comes up every time someone mentions the corruption.
We don't power off our many pis, but they are on UPSs (we use them for a security system.) However, the corruption happens so much that we keep disk images and have a spare on hand when we have to reboot them for any reason because 1/4 of the time they will not boot up.
Even if it were corrupting the FILES being written when hard booted, it shouldn't corrupt the FILESYSTEM being written.
TLDR, nuh uh.
Re: Add a dirt-cheap screen to the Raspberry Pi B+
#23Earlier quoted context omitted.
This comes up with every Pi post on HN for some reason, but if you're getting SD card corruption you either have a bad card (check the known good cards: http://elinux.org/RPi_SD_cards ) or are not shutting the Pi down correctly. You absolutely cannot just pull the power cord out while booted up because the SD card might be in the process of writing and you'll easily corrupt it. Make sure you always run 'sudo shutdown…
This comes up every time someone mentions the corruption. We don't power off our many pis, but they are on UPSs (we use them for a security system.) However, the corruption happens so much that we keep disk images and have a spare on hand when we have to reboot them for any reason because 1/4 of the time they will not boot up. Even if it were corrupting the FILES being written when hard booted, it shouldn't corrupt t…
> Even if it were corrupting the FILES being written when hard booted, it shouldn't corrupt the FILESYSTEM being written.
That's not how SD cards work unfortunately. When an SD card erases data, like if it's updating a file allocation table, it has to erase an entire block of flash and not just the bytes you care about. The card will throw the block into a cache in memory, erase the block, and then rewrite the parts of the block that weren't erased. However if you pull out power during that operation you'll completely kill the block and destroy the filesystem.
There's a great video here from Linuxconf Auckland about using SD cards for embedded systems and these issues: https://www.youtube.com/watch?v=K3zb6p0thQU
Re: Add a dirt-cheap screen to the Raspberry Pi B+
#24Earlier quoted context omitted.
This comes up with every Pi post on HN for some reason, but if you're getting SD card corruption you either have a bad card (check the known good cards: http://elinux.org/RPi_SD_cards ) or are not shutting the Pi down correctly. You absolutely cannot just pull the power cord out while booted up because the SD card might be in the process of writing and you'll easily corrupt it. Make sure you always run 'sudo shutdown…
>You absolutely cannot just pull the power cord out while booted up because the SD card might be in the process of writing and you'll easily corrupt it. False. This depends on the software. We developed a system for the PrintToPeer Raspberry Pi OS that uses the RAMdisk for read/write operations, and makes the rest of the operating system read only. You can uplug it whenever and nothing is corrupted.
Sure, but 99% of Pi users are going to use the default Raspbian OS and won't have the luxury of a ramdisk and read-only filesystem.
Re: Add a dirt-cheap screen to the Raspberry Pi B+
#25Wow, didn't know that you could do this with the Pi. People have been doing this with the Cubieboard since it came out[1], but to be honest I'd always assumed the Raspberry Pi display outputs were as tightly locked down behind the binary GPU blob as the CSI camera connector.
[1] See for instance http://linux-sunxi.org/Cubieboard/LVDS - I believe it supports DPI as well as LVDS. script.fex is basically Allwinner's equivalent of the device tree.
Re: Add a dirt-cheap screen to the Raspberry Pi B+
#26Earlier quoted context omitted.
This comes up with every Pi post on HN for some reason, but if you're getting SD card corruption you either have a bad card (check the known good cards: http://elinux.org/RPi_SD_cards ) or are not shutting the Pi down correctly. You absolutely cannot just pull the power cord out while booted up because the SD card might be in the process of writing and you'll easily corrupt it. Make sure you always run 'sudo shutdown…
This comes up every time someone mentions the corruption. We don't power off our many pis, but they are on UPSs (we use them for a security system.) However, the corruption happens so much that we keep disk images and have a spare on hand when we have to reboot them for any reason because 1/4 of the time they will not boot up. Even if it were corrupting the FILES being written when hard booted, it shouldn't corrupt t…
The metadata logging on modern Linux filesystems is designed with the consistency guarantees offered by spinning magnetic storage in mind. SD cards (and SSDs for that matter) are completely different - pull the plug when the card is busy updating its internal block indexes and you’ll corrupt a big chunk of the card & no filesystem level metadata logging is going to prevent that.
If you could use a flash filesystem at the OS level & talk directly to the SDcard flash blocks then you might be able to pull the plug & not risk corrupting an SDcard, but as things currently stand I don’t think that’s possible.
Re: Add a dirt-cheap screen to the Raspberry Pi B+
#27This is an awesome post. A number of older laptop screens use this "standard" and you can just take off the screen and repurpose it. The trick is that sometimes the flex cable between the screen and the laptop has extra stuff on it.
Time to go panel hunting for some more panels :-)
Re: Add a dirt-cheap screen to the Raspberry Pi B+
#28Maybe they can tackle the long-lived, widely-experienced SD card corruption issues of the RPi in the next version instead of adding a bunch more pins and an extra core. Meanwhile the competition even has eMMC in the same price range.
This comes up with every Pi post on HN for some reason, but if you're getting SD card corruption you either have a bad card (check the known good cards: http://elinux.org/RPi_SD_cards ) or are not shutting the Pi down correctly. You absolutely cannot just pull the power cord out while booted up because the SD card might be in the process of writing and you'll easily corrupt it. Make sure you always run 'sudo shutdown…
A possible third reason is a poor connection to the SD card. I was recently using an SD card that was quite flimsy (presumably it was only designed to work when it was also held from the back, which the RPi SD connector does not do). Even when it manged to boot, soon after the card would flex back and the device would go missing. I switched to a micro SD card in a much stiffer adapter (what I had laying around), and then ordered a smaller microsd adapter (http://www.ebay.com/itm/271679029684) so the thing doesn't even stick out, which will keep it from getting knocked around.
Re: Add a dirt-cheap screen to the Raspberry Pi B+
#29This really should be the next thing the RPi team tackles, IMO. It's nice we have this great cheap computer, but trying to find a screen to plug into it is terrible. A computer monitor or TV is fine, but both of them draw too much power and are far too big and stationary. And have you seen the prices of small HDMI screens? I can buy a 8" Windows tablet, full PC mind you, for the price of a single 5" HDMI screen. Far…
If you want a screen, just buy a $50 tablet. The Raspberry Pi is basically a tablet computer chip minus the tablet.
Re: Add a dirt-cheap screen to the Raspberry Pi B+
#30This really should be the next thing the RPi team tackles, IMO. It's nice we have this great cheap computer, but trying to find a screen to plug into it is terrible. A computer monitor or TV is fine, but both of them draw too much power and are far too big and stationary. And have you seen the prices of small HDMI screens? I can buy a 8" Windows tablet, full PC mind you, for the price of a single 5" HDMI screen. Far…
I'm also still waiting for this one: http://techcrunch.com/2014/10/21/pi-pads/ It looks like the official site is down atm but they mention an introduction in 2014 in their FAQ. It's a 640x480(!), 7" touchscreen.