[amsat-bb] Re: ISS Message Board
Gordon JC Pearce
gordonjcp at gjcp.net
Wed Jul 27 15:01:19 PDT 2011
On Mon, 25 Jul 2011 19:30:50 -0400
Diane Bruce <db at db.net> wrote:
> On Mon, Jul 25, 2011 at 03:43:03PM -0700, Ted wrote:
> > Curious..
> > If Gordon (always ready with a cheerful comment) is accurate, then what is
> > the purpose of the BBS? Also, Kevin is far from 'selfish'...he is just using
> The BBS is a side effect of the commercial equipment (Kenwood) they took
> up there. Many of us do think it should be disabled.
Time for a quick description, for those who may be less familiar with how packet BBSes work.
Many of us are running packet radio BBSes or even just mailboxes, on modern computing hardware. Now this hardware with 16- and 32-bit processors running at clock speeds of over 100MHz, up to a megabyte or even more of RAM and maybe as much as a couple of gigabytes (that's 1024 megabytes) of mass storage is often capable of handling many simultaneous connections. Users can send messages to each other directly or via mailboxes, while other users are simultaneously reading messages or browsing saved bulletins - perhaps as many as eight users at once!
By comparison, the 8-bit 4MHz microprocessors used in most normal TNCs can really only cope with a single connection at a time. Once someone is in connected mode, everything else gets rejected. Some of the more modern TNCs can accept very large amounts of RAM (the KPC-3 can have 32 kilobytes), but most have much less than that. The TNCs built into radios tend to be fairly simpleminded beasts, with crude firmware and very little RAM for storing messages and connections.
The UI packets, on the other hand, are merely received and, if they are valid, repeated (almost verbatim) a moment later. There is a slight modification to the header to indicate that they've been through a digipeater, but the message content remains unmodified. Since the TNC has no need to track any state for these packets - UI is not a connected mode - then it can handle digipeating packets for any stations it can hear.
> > the available resources. Helpful education is far more useful than lame name
> It's the way Gordon is, he's a nice chap online (on IRC). Don't take it
> the wrong way. The pair of you should go have a beer together or something.
> He's just a typical dour direct Scot, but he will drink you under the table. ;-)
Thanks, that's the nicest thing anyone's said all day.
Gordon JC Pearce <gordonjcp at gjcp.net>
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