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Ward Christensen (of BBS and XMODEM fame) has died

(en.wikipedia.org)
322 points DamonHD | 1 comments | 13 Oct 24 15:39 UTC | HN request time: 0.196s | source
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sokoloff ◴[13 Oct 24 16:58 UTC] No.41829570[source]▶
RIP.

My first paid programming gig ($20) was implementing the XMODEM checksum in 6502 assembly for a BBS sysop who had bought an early 1200 baud modem, only to find that his Atari BASIC BBS software was computing the checksum so slowly that it still created slowdowns in file transfers and needed a USR() that could compute it faster.

I learned a lot about protocols and algorithms from that exercise (now trivially simple, but wasn't for me at the time).

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fsckboy ◴[13 Oct 24 19:25 UTC] No.41830789[source]▶
>an early 1200 baud modem...needed a USR()

what's a USR()?

asking cuz USRobotics was a modem company

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1. renewedrebecca ◴[13 Oct 24 19:30 UTC] No.41830825[source]▶
Usr() is a way to call out to a machine (assembly) language subroutine from BASIC.