On Friday 01 June 2018 06:20:59 Richard Owlett wrote: > On 05/31/2018 10:07 PM, Stefan Monnier wrote: > >> I have two computers with USB ports. > >> I wish them to communicate as simply as mid-20th-century computers > >> did. > > > > What kind of "communicate" do you need there? > > Essentially any ;/ > In fact one of the thought experiments I was pursuing was how to do > file copying/sharing over RS232 - even I would not actually attempt to > implement.
Other than speed of the copy while the error correction verify's it sector by sector, why not. Both rsync and rzsz are quite capable of sending a file halfway around the planet with the last 17 miles on a barbed wire fence. And getting identical crc's in the final check. For a circuit that was actually that dirty, I think I'd choose rzsz as its default packet size is 256 bytes. If the crc of that packet fails, it requests a resend until it gets it right. So does rsync, but rsync's default packet is 64k, demanding a far cleaner path. rzsz unforch has several cousins 3x removed, so there is less than 100% compatibility. And the linux version is one of the worse compatibility violators. > > The "way back machine" to simulate a "null modem" serial cable > > exists, as you've seen, but it's rarely the best solution for > > nowadays's needs, > > "Best" is not an invariant absolute. > > > since nowadays connecting two computers is something completely > > normal, supported by a deluge of tools, but they all expect a > > "network" connection rather than a serial cable. > > > > In most cases those two computers also have ethernet or wifi "ports" > > so you can connect them via such a network (which usually offers > > faster transmission than a serial cable, lets you seamlessly > > multiplex several connections, and lets you use the many tools > > working over the network to connect computers). > > An explicit requirement is a wired, NOT WiFi, connection. > I that seriously. My internet access is a WiFi hotspot with its WiFi > capability disabled. > > > In some cases one of the two computers's USB port is an "OTG" port, > > meaning that it can act either as "master" or not, in which case you > > can just use a regular USB cable (and usually you then configure the > > OTG side to pretend it's a network card, so it ends up looking to > > the software like you've connected the two machines via an ethernet > > cable. That's what I use between my BananaPi "router" and my office > > desktop). > > I saw it and it meets most (all?) my requirements except my reading > suggested: > 1. obsolete > 2. available only for Windows/Mac > 3. no way to determine if any of machines were equipped > > > If none of that are options, you can resort to using an "ethernet > > dongle" on both sides and an ethernet cable between the two. > > That's a 1 versus 3 items required per connection. > > > All of those things will typically work "out of the box" on a > > vanilla Linux kernel (the usbnet drivers have been incorporated > > years ago). > > > > Oh, and in case those computers are somewhat old, they may also come > > with Firewire ports, and those (contrary to USB) don't have the > > "slave/master" distinction so you can connect your computers this > > way with a plain normal Firewire cable (and make it appear to the > > software, again, as some kind of ethernet-like connection). > > > > > > Stefan -- Cheers, Gene Heskett -- "There are four boxes to be used in defense of liberty: soap, ballot, jury, and ammo. Please use in that order." -Ed Howdershelt (Author) Genes Web page <http://geneslinuxbox.net:6309/gene>
