can someone refresh my memory on binary transfer speeds for ZMODEM over USR HST reddit / bbs ---------------------------------------------------------------------- DosGuru · 2022-12-08 15:16 My memory is extremely fuzzy. Does anyone have any anecdotal memories on how long it took to download compressed binary data over ZMODEM back in the USR HST days? Also, I remember Ymodem-G being slightly faster due to more lax error correction IIRC transferring \*ahem\* warez over 2400 baud I \*think\* i was getting about 100kb every 15 minutes? Does that sound right? ​ \*\*EDIT\*\* i had initially done some back of the napkin math, but realized the theoretical transfer speeds on paper didn't line up with real world transfer speeds due to variables like connection quality and compression ---------------------------------------------------------------------- mixedliquor · 2022-12-08 15:45 Sounds a tad slow but not that far off. A baud is roughly 1 bit per second, so 2400 baud is roughly 300 bytes per second, less some overhead. Using that math I came up with about 250kbytes in 15 minutes. ---------------------------------------------------------------------- DosGuru · 2022-12-08 15:58 i tried that at first, but I came to the conclusion that theoretical transfer speeds were off because of a number of variables - connection quality, and compression over zmodem ---------------------------------------------------------------------- Quicken2k · 2022-12-08 16:26 Ahh the memories of my 1200 baud modem. ---------------------------------------------------------------------- waftedfart · 2022-12-08 17:23 Without accounting for protocol overhead, 2400bps/baud = 300 bytes per second. 100,000 bytes / 300Bps = 333 seconds. 333 / 60 = 5.55 minutes. Or, 0.0024Mbps... ---------------------------------------------------------------------- mixedliquor · 2022-12-08 17:36 I don’t recall zmodem being significantly faster, just better at recovery. I recall speeds around 1.2-1.5kbps over a 14400 minutes which is about 80% of the theoretical max bandwidth; seems appropriate to account for overhead, CRC, etc. Edit: we need more love for KERMIT. ---------------------------------------------------------------------- UM-Underminer · 2022-12-08 18:24 That roughly lines up with my memory; I seem to recall allocating ~1hr/MB on 2400 ---------------------------------------------------------------------- jlaux42 · 2022-12-08 18:48 My memory is that HST started at 9600bps and went up from there, with varying degrees of proprietary compatibility (or lack thereof) with lagging industry standards for other brands. Assuming a clean direct connection without unusual latency issues you'd expect to transfer around 1K per second, 600K in 10 minutes, 3.6MB in an hour, etc. ---------------------------------------------------------------------- hedgecore77 · 2022-12-08 22:01 Z modem would top out about 3-3.5kps at 56k. If I remember right, at 14.4 it would be between 1.5kps and 1.8kps. ---------------------------------------------------------------------- hedgecore77 · 2022-12-08 22:01 Mine was on a C64 :) ---------------------------------------------------------------------- WWIVPENGUIN · 2022-12-09 00:10 It didn't transfer much faster, but because if it's ability to recover and how it could selectivity retransmit corrupt blocks in smaller chunks and use variable compressions the transfers were noticably quicker to finish, especially on poor connections. ---------------------------------------------------------------------- 13_0_0_0_0 · 2022-12-09 02:28 Since we’re going down memory lane… mine: 300 baud acoustic coupled (found in the trash from a phone company) on an Atari 400 1200 on an Apple IIc 1200 baud on C64, then 2400, then 9600 9600 on pc clone, then 28.8, and eventually the standard usr 56k Bonus: isdn 128k, then cable, then a T1 (work paid for it, that was weird). Also had a cpdp modem in the late 90s. It was a trip using VNC at 9600 baud on a black & white (no grayscale) palm pilot to access my Linux box at home. This was a few years before cell days was offered, at the time it was mostly for fleet management and law enforcement. The perks of working for a telco isp :) ---------------------------------------------------------------------- RooR67 · 2022-12-09 02:42 I miss BBSes ---------------------------------------------------------------------- Quicken2k · 2022-12-09 04:08 Wow. I remember all that. I feel old now. ---------------------------------------------------------------------- veeb0rg · 2022-12-09 04:18 They still exist, some you can still even dial into. Granted they're no where near as plentiful as they use to be. ---------------------------------------------------------------------- BrundleflyUrinalCake · 2022-12-09 07:19 I remember it being a bit less than that… 14.4 got me around 1.2k/s on zmodem I believe. ---------------------------------------------------------------------- hedgecore77 · 2022-12-09 09:55 Are you thinking of Xmodem? That was slower, but I can't remember if I switched to Z modem when I was at 14.4 or 9600... What was that bidirectional protocol that had chat built in? ---------------------------------------------------------------------- BrundleflyUrinalCake · 2022-12-09 15:39 I recall all bauds being available to all modems. I believe modem transferred 100 bytes at a time and zmodem bumped it up to 1k chunks. ---------------------------------------------------------------------- cAPTAINkNZ · 2022-12-10 09:21 Hydra? ---------------------------------------------------------------------- hedgecore77 · 2022-12-10 10:04 HSLink I think! I googled it to confirm and found this. Enjoy the walk down memory lane. ;) [Protocols](http://archives.thebbs.org/ra90c.htm) ---------------------------------------------------------------------- mro1337_000 · 2022-12-18 03:25 on 14.4 it was like a half an hour for 1MB ---------------------------------------------------------------------- litecoinboy · 2022-12-18 06:15 Ditto