Date : Sat, 31 Oct 2009 11:09:29 -0000
From : famrowland@... (Andrew Rowland)
Subject: Econet packet size
When did Econet start using variable packet sizes? Back when I as using
Beebs on Econet it was fixed at 256B, IIRC. Hence the poor performance of
OSBPUT and OSBGET until that school in Cambridge -- Newhall School? -- came
up a proper buffered version, which Acorn incorporated into the next release
of NFS. I remember that was a much-awaited upgrade! Barnsley LEA got the
chips in bulk to upgrade all the Econet stations in the LEA.
Andrew
-----Original Message-----
From: bbc-micro-bounces+famrowland=freeuk.com@...
[mailto:bbc-micro-bounces+famrowland=freeuk.com@...] On
Behalf Of Rick Murray
Sent: Sat, 31 October 2009 00:25
To: BBC MailList
Subject: [BBC-Micro] Econet packet size
I remember recently a discussion on Econet packet sizes. Was idly reading
stuff on the MDFS server, and I came across this paragraph:
--8<--------
The econet is a low cost, moderate speed (50-300kBit/S on-net) network for
connecting together microcomputers. It allows one machine to transmit a
packet of data to another which has a suitable reception enabled to receive
that data. A packet contains at least one byte, and at most 1280 bytes, of
data.
--8<--------
Source: http://mdfs.net/Docs/Comp/Econet/RISCiX.txt
It is an undocumented Acorn document. RISCiX is an ARM based system that
was, I believe, a Unixy contender to RISC OS that never quite caught on.
The Rxxx workstations (looking a lot like souped-up A440s to me!). That
would date it late-80s. I would imagine the 1280 is likely a limitation of
the 6502-based machines, >1K is a lot in a 32K computer! At any rate, this
seems the Acorn-quoted value so reasonable to figure it is reliable enough.
FWIW, skipping the ARM/RISCiX stuff, this document is a lengthy but pretty
complete introduction to the ins and outs of how Econet works.
Best wishes,
Rick.
--
Rick Murray, eeePC901 & ADSL WiFI'd into it, all ETLAs!
BBC B: DNFS, 2 x 5.25" floppies, EPROM prog, Acorn TTX
E01S FileStore, A3000/A5000/RiscPC/various PCs/blahblah...
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