ZMODEM • Hacker News Board

Re: ZMODEM

#61

Post by linker3000 » Sat, Oct 22, 2016, 8:04 PM UTC

tyingq wrote: post #9

Kermit was in the same space as Zmodem. I remember it fondly, as they were very progressive around "open source" way back in the early 90's, and probably earlier. They accepted what was essentially a "pull request" over USENET discussions forums from me to add a feature. http://www.kermitproject.org/ckfaq.html

I remember receiving a 2400' tape for our VAX 11/750 from Lancaster University (UK) containing a full dump of their Kermit repo. Having pulled off the relevant VAX/VMS, PC and various other program formats, we had a way to transfer files between a number in-house development systems. This would have been about 1983.

Re: ZMODEM

#62

Post by sllabres » Sat, Oct 22, 2016, 8:20 PM UTC

anexprogrammer wrote: post #41

ptaipale wrote: post #36

Earlier quoted context omitted.

Yup, the first problem with Xmodem was that it transferred sectors (as in CP/M) and thus file size was always padded with zeros to a multiple fof 128 bytes. Then came Ymodem which fixed this, and then Zmodem which was considerably faster (windowing protocol) and allowed resuming interrupted transfers and handled CRC checksums.

The resume was the clincher. You'd spent over an hour getting 3/4 the way through downloading an enormous 1M file to drop to line noise. OK, start again... Saving 400+ for a Courier HST to go an insanely fast 12k (very rarely). They beat everything else at holding a line though.

Saving for a Zyxel and get 16800 :) Lots of good memories for the Elite 2864ID (ISDN) and U-1496E.

I had a project ~15 years ago with several thousand FAX Clients, and interestingly we had problems with every hardware card or modem we used except the (even then quite old) U-1496E which worked without flaw, whatever customer send data.

Re: ZMODEM

#63

Post by scoopr » Sat, Oct 22, 2016, 8:25 PM UTC

All the cool kids used SModem, which allowed for downloading and chatting at the same time!

Re: ZMODEM

#64

Post by jcadam » Sat, Oct 22, 2016, 8:28 PM UTC

chrisfinne wrote: post #12

This submission is a ploy by the NSA and advertisers to further refine their demographic slot of "old hackers". Kermit, zmodem, bbs, baud. South Park's Member Berries are in full force here. CoCo forever!

Or recruiters are adding everyone who responds to their 'too old/overqualified' blacklists.

I miss the BBS days. Very few non-geeks around. The internet just isn't the same.

Re: ZMODEM

#65

Post by qwertyuiop924 » Sat, Oct 22, 2016, 8:40 PM UTC

rsync wrote: post #48

qwertyuiop924 wrote: post #33

Earlier quoted context omitted.

>At the time, it what somewhat novel to be able to get the source code at all Really? IIRC, in Jason Scott's excellent BBS documentary (you should go watch it. Like, right now. It's that good), Thom Henderson (from SEA. Remember them? I don't, because I wasn't alive. Which is why I have to rely on documentaries) said that it was expected in UNIX circles, which is where Kermit originated. Or were you on PC? I don't kn…

"... Jason Scott's excellent BBS documentary (you should go watch it. Like, right now. It's that good)" Agreed. The BBS documentary is superb and really, really entertaining and engrossing. Especially the episode(s) on fidonet.

I honestly found the compression and artscene episodes more interesting than fidonet. Although fidonet was good too.

Re: ZMODEM

#66

Post by jejones3141 » Sat, Oct 22, 2016, 8:47 PM UTC

dmd wrote: post #45

My impression of zmodem and kermit, from 13 years ago (remembering then from a decade prior's use): http://dmd.3e.org/2003/12/zmodem-vs-kermit/

Kermit's design accommodated connections that zmodem couldn't (half-duplex, connections that don't let one send some control characters. seven bit connections, or connections between systems using ASCII and systems using EBCDIC), and the basic protocol was easy to write. You could use Kermit to send data between your C-64 and a Cray 1 or Burroughs Large system--and it was used to send data from the International Space Station to earth. Later versions supported sliding windows and large packets where possible and let one selectively quote characters, while still providing backwards compatibility with earlier versions.

Re: ZMODEM

#67

Post by hansjorg » Sat, Oct 22, 2016, 9:00 PM UTC

anexprogrammer wrote: post #3

> Introduced 1986; 30 years ago Now I feel old. I remember when this was new and clever. Made downloading from BBS's much nicer over XModem. At 2400 baud or whatever was current then!

I got my first modem in 1990 or thereabouts. For some reason there was still a lot of XModem use back then, but it was gradually replaced by ZModem.

Some years later, just before BBSes were obsoleted by the internet, several multiplexing protocols appeared which let you chat or play a MUD while downloading or even upload and download at the same time.

Can't remember any names, but these protocols were only popular for a very brief time before the internet took over.

I also recall some BBSes survived a while into the internet age by adding telnet ports. You ran your normal dialer software with a telnet driver that took the hostname as the phone number and then would end up running ZModem and the likes over telnet.

Re: ZMODEM

#68

Post by bane » Sat, Oct 22, 2016, 9:04 PM UTC

wvenable wrote: post #46

hilop wrote: post #28

Looking b ack at stuff like Zmodem, it's instructive to compare the computing culture then and now. Back then, everything was so cryptic . Documentation was hard to find printed books, code and config was extremely abbreviated ( sometimes for legitimate technical reasons of storage capacity). It was all very off-putting unless you put w lot of effort into research, or ran in the social circles that already had data a…

The most striking thing to me was there was a huge amount of free-as-in-beer software powering the entire BBS "network" and lots of helpful communities but almost nothing was open source.

It's kind of weird how certain computing platforms that died around this time period have frozen in time this aspect of the modern "sustainment" movements. For example, the Amiga scene these days is full of high-effort oddball software and hardware projects that are closed source and for sale (and likely to earn their creators literally dozens of sales).

Re: ZMODEM

#69

Post by blank_dan » Sat, Oct 22, 2016, 9:31 PM UTC

I'm disappointed that the wikipedia article makes no mention of Yam. Which boasted of the worst user interface ever invented.

Re: ZMODEM

#70

Post by mbreese » Sat, Oct 22, 2016, 9:37 PM UTC

stevefeinstein wrote: post #25

It's still hard to match the convenience of moving files to and from a server with RZ/SZ. If your terminal emulator supports it, it will see the trigger sequence emitted and start the modem protocol over your ssh connection and save the file. Since it runs over your current ssh connection it's perfectly secure. It's so much easier then switching to a local terminal to use scp to get or put a local file. Sure, I know…

Apparently iTerm2 can be used to setup lrzsz coupling [1]. I haven't tried it yet myself, but I'm going to! I really hope this works. It's such a pain to setup scp back to my workstation that if I need to do any real back and forth, I've been known to setup a reverse SSH tunnel just for getting scp to work. But even then, it's a pain. Zmodem would be so much easier (and make me a little nostalgic inside every time I used it).

[1] https://grack.com/blog/2011/10/26/automatic-file-transfer-in...