asciilifeform: anyway i dun think this is critical for any current application. but ideally would like to be able to take a checksum without leaking what-of
asciilifeform: ( even very small table can end up crossing page boundary )
asciilifeform: ave1: tables on pc are unconstanttime, on acct of cache
asciilifeform: but if i'm overwriting a 8TB disk prior to taking it to crematorium, i'd rather urandom, i dun presently have a 200M/sec rng
asciilifeform: but yes if you're picking the next piece to fall in 'tetris', just use own prng☟︎
asciilifeform: reading a legit /dev/random ( or FG, or any other device ) is a ~blocking~ op, potentially returns in a year if you're entropy-poor , or even rich but 9000 processes want it
asciilifeform: http://btcbase.org/log/2018-10-12#1860778 << there are not so many legitimate uses for /dev/urandom. however the idea that it can be fully reproduced in userland without kernel knob is afaik a mistake -- the thing gives you real entropy if available, and elsewise prngolade; importantly, as a ~nonblocking~ operation. idea is that it ~always~ returns in constant time.☝︎☟︎
asciilifeform: http://btcbase.org/log/2018-10-12#1860762 << that was the contemplated stat(), yes. the sad is that idjit unix does not have a general-purpose 'this block of program is atomic' primitive, and so other cpu can fuck you b/w the stat() and open() call ( tho phf did find a open() flag that supposedly atomicises )☝︎
asciilifeform: phf: seems like oughta work ( aside from boxes where /tmp is on nfs drive, but that's a perversity imho )
asciilifeform: ( and it is my understanding that you can, under all known unixen, simply by locking e.g /tmp/tmsr or whatever fixed path )
asciilifeform: if you can check for collisions atomically, may as well have ordinary counter .
asciilifeform: really imho oughta be solvable without exotica.
asciilifeform: phf: if vpatch in particular cannot be made to work 100% reliably on existing kernels, we'll have bootstrapping boojum.
asciilifeform: if you have a working rng, all you gotta do is take 256 bits from it, and no need to stat() or anyffing; the chance of collision is coupla orders of magnitude smaller than asteroid flattening the machine
asciilifeform: i suspect however that any solution that works across generic unixdom (i.e. doesn't marry linux) will appear similarly ugly
asciilifeform: phf: also can lock a fixed name in /tmp when incrementing counter or whatever wants to be atomic. tho imho it's ugly
asciilifeform: phf: counters won't behave well with '9000' parallel processes.
asciilifeform looked, didn't find, assumed that i simply didn't look hard enuff
asciilifeform: phf: there's no atomic file create-or-die ?
asciilifeform: phf, bvt : i thought of a possible algo for sane tmp file creation that dun need rng or global counter. 1) pick a file name in tmp dir, if none exists, take empty string, as string S 2) produce S' = H(S) , H is hash (e.g. keccak) 3) stat(S') ; if already exists, take S'' = H(S') and repeat .☟︎
asciilifeform: nao if only somebody still made a b&w panel with reasonable res...
asciilifeform: trinque seems like they're sold by the crate nao, on lulzbay & elsewhere.
asciilifeform: also somewhat unusually, there's a full datashit for the thing ( i.e. could drive with fpga; and there's a chinese hdmi/dvi board for it, ~20bux )
asciilifeform: pretty clever, imho : they had some electrochemical mechanism for turning the colour filters on subpixels into transparent.
asciilifeform: draws 400mW in reflector mode (~1/5 of what colour panel of that weight class eats) .☟︎
asciilifeform: !Q later tell phf i recently found that lcd panel made by (defunkt) 'pixelqi co', pq3qi-01 , is still sold by chinese ( i have nfi if clones, or old stock ), ~100 $ ea; the thing toggles from 1024x600 colour/backlit into a 3072x600 greyscale reflector thing, worx with various lappies ( sadly not x60, it's a 16:9 )☟︎☟︎
asciilifeform: i dun really see a massive win from it, tbh
asciilifeform: hrm, apparently the 'record' pheature is a '30 day trial', aol-style, and after that is +7orcbux/mo. i'ma switch it off unless somebody reeally wants it
asciilifeform: mircea_popescu: i'ma gpg you the login to the stats page later today
asciilifeform: !Q later tell mircea_popescu 1-833-867-7282 ( "1-833-TMSRBTC" ) ready, if vendor to be believed; ( not tested yet ) . worx in usa strictly, like all 8xx .
asciilifeform: ( presently, the 'model f' thing, in the past, others )
asciilifeform: btw folx read '>25 yrs' and laugh, but i have 30+y.o. iron on my desk even nao, working.
asciilifeform: if i ever find that mine stopped, whole thing is going to dissection table, fg, comp, power supplies, etc
asciilifeform: betcha it would, if usg.cisco.crapple had built it..
asciilifeform: mircea_popescu: btw recall that we have red lamp already ( iirc i suggested claxon too, back in the design days, but mircea_popescu said enuff-is-enuff )
