Re: To Upgrade or Not. What's the difference?

In message <4647392b$0$19248$da0feed9@xxxxxxxxxxxxxx>
Rob Kendrick <nntp@xxxxxxxx> wrote:

John Cartmell wrote:
In article <41444fe24e.pittdj+@xxxxxxxxxxxxxxx>, David Pitt
<news@xxxxxxxxxxxx> wrote:
I think I am right in saying that the A9home is USB1.1 only. (The Iyonix
has the faster USB2.)

I don't think you can simply compare the speeds of the two specifications. I
think individual implementations can vary from the specification (presumably
by exceeding it/them) and I don't know if, or by how much, the Iyonix and the
A9 exceed the relevant specs. Anyone know?

This is just the sort of stupid answer that so irritates. Having the
two machines together it is obvious to any sentient being that the the
Iyonix USB is well in front of the A9home's.

It's pretty difficult to "exceed" the USB specs, due to the way the
signalling works. However, neither the A9 Home or the Iyonix are likely
to be able to fill USB 2. (That is not to say that having USB 2
provides no advantage.)

The causes for this will be much the same as to why the Iyonix won't be
able to fill its Gigabit ethernet interface.

For a rough and ready test of USB performance to show the difference
between the two implementations I copied a 25MB file to a pen. It took
1m55s on the A9home against 15s on the Iyonix.

!USBinfo has 480Mb/s for USB2 and 12Mb/s for USB1, 40:1 then, an over
simplified theoretical maximum ratio. The ratio here with my real
world test was 7.7:1. Neither transfer was anywhere near the
'maximum'.

--
David Pitt.

Computing with RISC OS.
.

Relevant Pages

  • Re: To Upgrade or Not. Whats the difference?
    ... I don't think you can simply compare the speeds of the two specifications. ... by exceeding it/them) and I don't know if, or by how much, the Iyonix and the ... It's pretty difficult to "exceed" the USB specs, ... neither the A9 Home or the Iyonix are likely ...
    (comp.sys.acorn.apps)
  • Re: A9 Home
    ... same performance (that label being USB 1.1). ... performance of the a9home. ... you aren't going to say anything about the USB 2 performance of the Iyonix ... Steffen said that the speeds were similar. ...
    (comp.sys.acorn.hardware)
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    (comp.sys.acorn.misc)
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  • Re: Simtec v Castle USB
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