Andrew Ball | 5 Oct 2007 18:27

A7000 RAM SIMMs


I have read that the A7000 takes "standard" 72-pin SIMMs, but it's not
clear to me whether these must be EDO, FPM, whether parity is required
or how fast they must be.  Does anyone here know?

- Andy.

Stephen Borrill | 5 Oct 2007 18:59
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Re: A7000 RAM SIMMs

On Fri, 5 Oct 2007, Andrew Ball wrote:
> I have read that the A7000 takes "standard" 72-pin SIMMs, but it's not
> clear to me whether these must be EDO, FPM, whether parity is required
> or how fast they must be.  Does anyone here know?

A7000 or A7000+? The latter wants EDO, the former not (though you'll 
probably get away with it).

All IIRC, of course :-)

--

-- 
Stephen

Andrew Ball | 5 Oct 2007 23:04

Re: A7000 RAM SIMMs


Hello Stephen,

  SB> A7000 or A7000+? The latter wants EDO, the former not (though
    > you'll probably get away with it).

Thanks for the information.  Is the A7000+ discernably faster than the
A7000?  Do both models include an ATA interface?  What is the capacity
limit for a hard disk?

- Andy Ball

Cathleen | 7 Oct 2007 12:00
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Ben Morrow | 7 Oct 2007 23:59
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Re: A7000 RAM SIMMs

Andrew Ball wrote:
> Hello Stephen,
> 
> SB> A7000 or A7000+? The latter wants EDO, the former not (though
>> you'll probably get away with it).
> 
> Thanks for the information.  Is the A7000+ discernably faster than
> the A7000?  Do both models include an ATA interface?  What is the
> capacity limit for a hard disk?

The A7000+ has a one-channel (two-device) ATA interface. I'm afraid I 
can't help with the rest...

Since you're writing to this list, I'm going to take a giant intuitive
leap and guess you're trying (or planning to try) to run NetBSD on an
A7000... if I'm wrong, please ignore me :). I have been trying
on-and-off to make this work for a while now, and have pretty much
failed: if you have better luck, I'd appreciate knowing how you did it
(off-list if you like). Of course, I would also be happy to share what 
little I've learned (and it really is little: unfortunately, my 
understanding of the internals of RISCOS is much less than I'd like).

Ben

Andrew Ball | 8 Oct 2007 03:23

Re: A7000 RAM SIMMs


Hello Ben,

  BM> I have been trying on-and-off to make this work for a while now,
    > and have pretty much failed...

I suppose it's good to find that out ahead of time. Apart from one for
myself (will they tolerate 240V at 60Hz?) I have thought about having
one set up at my parents' house, so that I can periodically send them
CDs with pictures of the 2-year-old granddaughter they have yet to
meet.  It might be simpler to send them a digital picture frame, but a
computer has more scope for additional uses. Ideally I'd put NetBSD on
it because I can manage that remotely, but if RiscOS is all it will
run, then I'll have to find (or perhaps write) software for that.

How far did you get?  What obstacles did you encounter?

- Andy Ball.

Stephen Borrill | 8 Oct 2007 09:56
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Re: A7000 RAM SIMMs

On Mon, 8 Oct 2007, Andrew Ball wrote:
>  BM> I have been trying on-and-off to make this work for a while now,
>    > and have pretty much failed...
>
> I suppose it's good to find that out ahead of time. Apart from one for
> myself (will they tolerate 240V at 60Hz?) I have thought about having
> one set up at my parents' house, so that I can periodically send them
> CDs with pictures of the 2-year-old granddaughter they have yet to
> meet.  It might be simpler to send them a digital picture frame, but a
> computer has more scope for additional uses. Ideally I'd put NetBSD on
> it because I can manage that remotely, but if RiscOS is all it will
> run, then I'll have to find (or perhaps write) software for that.

!SwiftJPEG.

> How far did you get?  What obstacles did you encounter?

I certainly had NetBSD running on an A7000 successfully some time ago. Did 
something get broken? I probably first used an A7000 for NetBSD around 
2002; it was a router/firewall with 2 network cards in - an EtherB in the 
NIC slot and an EtherIII as a podule.

Of course, a RiscPC would be better.

--

-- 
Stephen

Theo Markettos | 8 Oct 2007 13:22
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Re: A7000 RAM SIMMs

On Sun, Oct 07, 2007 at 10:59:48PM +0100, Ben Morrow wrote:
> Andrew Ball wrote:
> >Thanks for the information.  Is the A7000+ discernably faster than
> >the A7000?  Do both models include an ATA interface?  What is the
> >capacity limit for a hard disk?
> 
> The A7000+ has a one-channel (two-device) ATA interface. I'm afraid I 
> can't help with the rest...

The A7000+ is clocked at (I think) 48MHz while the A7000 is clocked at
32MHz, so there should be a significant speed difference.  The A7000+ also
has a floating point unit, though I don't know if things in NetBSD are ever
compiled for hard-float, and the EDO RAM might make a small difference.

For the disc interface, in terms of hardware, it's just a few bus buffers so
any restrictions are, in theory, purely with the OS.  RISC OS 4/6 can drive
up to 128GB (this is the limit of LBA28 addressing - RO6 doesn't yet support
LBA48).  The hardware only supports a few PIO modes so it's fairly slow (no
DMA).  RISC OS 3.7 can, in principle, format to the same sizes but the
Filecore E disc format has a map size limitation.  That means you start
getting things like minimum 16MB per file, and it all gets very inefficient
above about 10-20GB.  This won't bother you if you only format a small RISC
OS partition at the start of the disc and then NetBSD for the rest.

There is a small hardware problem on the Risc PC board that causes it to pay
attention to the /IOCS16 line from the hard drive which is long deprecated. 
Some modern drives, notably Hitachi, have stopped generating this signal
which means the motherboard only latches in 8 bits not 16 bits.  I'd assume
the A7000(+) board has the same arrangement, but don't have a schematic to
check.  More details here:
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