7 ms·
I'd expect the vast majority of IO requests to be served from the kernel's IO cache (we're talking 30 * 1.44MBs here so just under 50MB, trivial for even an old
by Nextgrid 4y ago
I'd expect the vast majority of IO requests to be served from the kernel's IO cache (we're talking 30 * 1.44MBs here so just under 50MB, trivial for even an old computer to hold in RAM), thus I wouldn't be surprised for it to be very fast and reliable as long as he sticks to read-only workloads - those would never actually touch the floppies beyond the initial read.
- reustle 4y agoIf we hit a lot of random sub folder URLs (that should all 404), would that trigger the webserver to check the drive to see if the file exists and skip the cache?
- jewel 4y agoNo. The cache is at the block layer, not the file/directory layer. So the filesystem will look up the directory structure, which will be cached.
- asveikau 4y agoOn top of the block layer cache there's also the namei cache for filename to inode lookups, I'm not sure if that covers a file not found case or just a success path, but it may apply here too.
- Vogtinator 4y agoYep, that's called a "negative dentry".
- asveikau 4y agoBut if a negative dentry does not yet exist, and a filename is requested for the first time, does it read from the fs? The DDoS scenario would be doing GET requests of random nonexistent filenames. You could change the name at every step so that the check for a negative dentry is never a cache hit.
- vocram 4y agoIf requesting http paths result in accessing the equivalent fs paths, then yes, you can dos it. But nowadays it’s uncommon for a webserver.
- asveikau 4y agoWell the point under discussion is that i/o from a floppy disk is slow. Most servers have much faster disks and it'd be absurd to consider this. Also the page/buffer cache would probably cache the FAT direntries so probably not a huge issue here.
- bch 4y agoStill backed by block layer cache for (hopefully) quick response regardless of outcome
- koverstreet 4y agoActually, no. There is no general block layer cache - the closest thing is the page cache, which is at the file level.
- rascul 4y agoAre you the Kent Overstreet working on bcachefs? If so, I've been watching it and looking forward for it to get into the kernel. Keep up the good work. I'll have a donation coming in a little while.
- koverstreet 4y agoThe one and only :)
- yencabulator 4y agoI guess the real question there is, does a directory count as a file for the purposes of this discussion. It seems necessary that the blocks storing the directory entries are cached too. Otherwise every non-existent lookup (that doesn't hit a negative dentry) would hit disk, each separately. So yeah, the page cache is keyed by file, but the system should still cache the directory structure.
- rootsudo 4y agoWould it be more fun to run a live cd webserver only? piece together an old computer, with an old live linux installation, and either run it unupdated or patched and carrying updates it can only apply w/o reboot?
- _joel 4y agoA Knoppix 4 CTF doesn't sound too challenging, tbf mate edit: thinking about it, there's some good educational value, but maybe via vm than plopped on the interwebs :D
- bee_rider 4y agoDo people do cyberpunk or sci-fi LARPs? An extravagantly unpatched server running on a raspberry pi or something like that would be a kind of fun prop.
- alasdair_ 4y agoThey do! http://cyberpunk.jackalope-larp.com/ http://cyberpunk.jackalope-larp.com/ is run both in-person and online at the same time and apparently has a pretty high production value.
- IntelMiner 4y agoI (briefly) ran an IRC server on a Sega Dreamcast based on the same ideas
- LarryPage 4y agoI did watch -n 1 'sync; echo 3 > /proc/sys/vm/drop_caches' to try and get around it. I think it's working, because boy is it noisy lol
- hotpotamus 4y agoI'm used to referring to lots of IO as "noisy" or "chatty", but then I imagine sitting next to 30 floppy drives and that brings it to another level.
- voxadam 4y agohttps://www.youtube.com/watch?v=kCCXRerqaJI https://www.youtube.com/watch?v=kCCXRerqaJI
- im_down_w_otp 4y agoThis is the greatest thing that anyone has done with any computer hardware anywhere, ever. This is more impressive to me than the moon landing. :-)
- voxadam 4y agoMake sure you check out his other videos including other compositions he's done. Star Wars theme: https://youtu.be/3KS02q0BUnY https://youtu.be/3KS02q0BUnY I Wat to Break Free: https://youtu.be/lbd06i9B2wU https://youtu.be/lbd06i9B2wU
- KuiN 4y agoMy favourite hardware music is this Radiohead cover from 2008. Blew my mind at the time https://www.youtube.com/watch?v=pmfHHLfbjNQ https://www.youtube.com/watch?v=pmfHHLfbjNQ
- tacker2000 4y agoThe scanners!! This is incredible!
- 4y ago
- tomxor 4y agoYup, even old computers that booted off floppy drives like the Atari ST and Amiga would often just load the entire data and program into memory, since their memory size was usually larger than the floppy disk. Same for the games, a lot of the loading at the beginning was to do with simply loading the entire disk into memory... basically system memory size vs block device size was the opposite way around of today... then again people could and did have many individual floppy disks.
- Aeolun 4y agoIf we take any portable media as the comparison, the largest I know of is 50GB for a blueray disk, that’s still something you can ‘almost’ load into 32gb of memory (if your OS and Teams app didn’t take 16gb of course).
- EvgeniyZh 4y agoI think thumb drives get up to several TB this days
- Aeolun 4y agoThat sounded a bit crazy to me, so I checked. I don’t think those are actually several TB. They’re fakes that are advertised as having several TB.
- EvgeniyZh 4y agoOk maybe not several TB, but 1TB seems legit https://www.bhphotovideo.com/c/product/1701503-REG/lexar_ljdp030001t_rnqng_1tb_jumpdrive_p30.html https://www.bhphotovideo.com/c/product/1701503-REG/lexar_ljd...
- semanticist 4y agoMicroSD cards - about the size of a fingernail - absolutely come in sizes up to 1TB, that's not controversial or dodgy brands selling fakes. There's many brands selling cards at 512GB, ten times your BluRay example. Portable flash drives using M.2 drives internally could reasonably be up to 8TB, but being at the high end they're expensive.
- madduci 4y agoIt depends on what you mean for 'old'. At the beginning of 90s even 16MBytes were pretty a luxury.