[Virtualacorn-list] VRPC Suddenly Become Very Slow

[T.O.M.S.]

On Mon Jul 21 21:00:26 BST 2014, David J. Ruck druck at druck.org.uk
sayeth:

> > The read/write transfer speed of the USB system is a small
>> fraction of the speed of a SATA or ATA drive, so I would have
>> thought that anything else accessing the USB system is almost
>> bound to interfere with VirtualRPC/RISC OS.

> Putting HardDisc4 on a USB stick should not cause that sort of
> slow down, RISC OS is very light on disc access, and most of
> the time wont be touching the disc at all.

I think that may be missing the point I was trying to make above
David.

This is that if something else is accessing the USB system - at the
same time as RISC OS is trying to read from or write to the
'HardDisc4' mount on the USB stick - then I believe that *will*
cause a mutual slowing down of disc access to/from 'HardDisc4', and
maybe trigger other knock-on problems.

On all our PCs, we have an additional VirtualRPC mount for a
high-capacity SD card in a card reader, purely as an additional
back-up medium. It is very noticeable how read/write speeds to these
SD cards is extremely variable.

I've just done a few rough-and-ready tests. If the card reader LED is
On/steady (no activity), then copying to or from the SD card is
reasonably fast (USB2).  But if the LED is already 'busy' (i.e.
flashing for reasons I know not), then read/write speeds to the SD
card are slowed right down.

And if I write or copy a multi-MB file to the SD card - and at the
same time do normal things under RISC OS, like editing a
document - that also slows down performance very noticeably. For
example, if typing text into a document, it can appear on-screen well
after being typed. In the worst case, we're talking seconds (although
no characters are actually missed off).

That's in full-screen mode so I dunno if the fps are similarly
affected. I must check on that.








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