Acorn Econet Fileserver

Tony Duell ard at p850ug1.demon.co.uk
Sat Nov 19 18:55:41 CST 2005


> 
> On Nov 19 2005,  2:14, Tony Duell wrote:
> > Are there any Econet enthusiasts here?
> 
> Yes :-)

Excellent. And as you saw, Lee Davison pointed me at your last reply to 
my question a couple of years back...

> > The mainboard contains :

[...]

> > 64K EPROM (2 off 27256). I've not tried to look at their contents yet
> 
> There are several versions of the firmware, each with its own little
> idiosyncracies ;-)  One EPROM is the MOS and the other is the
> fileserver code, as you might expect.

Yes, they've got labels on them saying 'MOS' and 'Filestore' or something 
like that. Next time I have it apart I'll see if I can find version 
numbers on them.

[...]

> > An Econet module (looks like the one used in a Master or Arc, the
> type
> > with the hardware collision detection). Oddly theres a 26LS30 on the
> > mainboard, does this thing source the Exonet clock too?
> 
> Yes, it does, and it's a decent asymmetric clock.  It's supposed to

What is the benefit of an asymmetic clock?  Or more precisely, why does 
it help?

> switch itself off (or actually, I suspect, not switch on at boot time)
> if it detects another clock already on the wire.

I would guess, without any evidence, that it detects the lack of clock 
using the same method that a Beeb uses to display the 'no clock' message 
and then enables the internal clock if necessary.

> > and a 34 pin
> > header. I am told this is to add a hard disk, and it looks similar to
> a
> > Beeb's 1MHz bus. I assume it takes the normal SASI host adapter and
> ST506
> > bridgboard (I have spares of those somewhere...)
> 
> Yes.

I am now confused. Your last message on this (the one Lee pointed me at) 
says it uses a SCSI and not SASI disk. I don't think the 34 pin header 
carries the SCSI signals (does it? -- I've not removed the PCB yet to 
look what it's connected to). Do I use the Acorn host adapter card and 
put a SCSI disk on the other side of it? Or is it a special host adapter 
that I haven't a hope of finding, or what?


> > On the front are 2 LEDs (power and mode) and what looks like a
> > reflectiove optoswitch (why?)
> 
> The optoswitch detects whether the front panel is in the open or closed
> state.  When closed, the box starts up as a server.  When open, it runs
> in maintenance mode.  The plastic "hinges" were rather fragile and
> frequently broke, leading sometimes to the loss of the cover.

Ah, right... Mine is missing the flap, althohgh I can see the holes for 
the 'hinges'. I will have to rig something up to operate the optoswtich...

More pressing is the lack of drives and cables. I assume the floppy 
drives are plain, 300 rpm, 80 cylinder, ones. Anyhting I should know 
about them?

> 
> > Can anyone tell me anything more about it, how to use it, what the
> > intenral links do, etc?
> 
> I should have the manual somewhere.  You shouldn't need to change any

If you find it, I'd be interested in seeing a copy...

> links.

No, probably not, but you know I am curious about such things anyway...

-tony



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