PDA

[Olly Betts]

On Tue, Jul 24, 2001 at 02:58:11PM +0100, Peter Wilton-Jones wrote:
> Totaly unrelated to previous emails - and I think this was answered in part
> before.
> I have a Palm Vx Handheld device using Palm OS 3.5.3 with 8MB of memory. Are
> there any plans to get survex running on this? It would probably be a
> difficult item to use underground (although easier than one with a keyboard
> due to mud and damp - cos you can keep it in a bag and still use it) but it
> would be very useful to colate the data on the surface during an expedition
> and process on the palm (if memory permits) and view the cave on it too -
> nothing special just an line survey for an basis.

I'd certainly like to get survex/spud working on palmtops/handhelds.  As you
point out they are much more feasible to take on an expedition to a remote
area, where it wouldn't be feasible to take a laptop.

The main challenges of porting any software to such devices is that the
screen is much smaller than even a low-end laptop or desktop machine,
the CPU is slow, memory is limited, and some models lack a keyboard.

Survex runs well on low-end hardware, so the CPU and memory limits shouldn't
be a problem.  Aven is a bit more memory hungry, but there's scope for
improvement there.

The lack of a keyboard means that everything in the UI ideally needs to be
doable without using a keyboard.  Having to pull up a virtual keyboard is
clumsy.

The small screen size means that you can't just compile up a piece of
software - it needs to be adapted to make it easy to use.  Wookey recently
got survex working on the Compaq ipaq running Linux, using xcaverot as the
viewer.  To make it usable, he had to reduce the size of the buttons and
indicators, and remove a couple of the buttons.  The ipaq "mouse" only has
one button, so he added an extra button to select zoom/rotate vs pan.

> You mentioed in the project spud spiel that there was little point in a palm
> as it's graphics weren't too good [...]

I think you've misunderstood what I said.  The Spud page on the survex web
site doesn't mention Palms at all - "Palmtops" is a generic term for such
devices.

> Is the general consideration that this will not happen or is there a
> lingering desire to include it?

I'm not ruling out porting to any handheld device, but there's a particular
problem with Palms - from what John Pybus has said, there's a C development
environment, but it doesn't even provide the standard ANSI C library.  The
memory management is also very different - there's not a distinction between
memory and disk.  This all means that a port is likely to be a major
undertaking.

John Pybus was experimenting with some simple surveying tools for the Palm
using some code from Survex.  I don't know what the status of these is -
John?

> I feel that the 2MB handhelds will struggle with any form of processing as
> they have so little memory but an 8MB one may be able to handle the
> processing of a 3d (equiv) file. Modern PALM handhelds come with expansion
> slots so these would be more than ideal.

Survex can still process usefully large surveys inside the DOS 640K limit.
It depends on the complexity of the survey, but I think I processed a 5000
leg survey in that limit with a recent Survex version, and cavern's memory
usage has decreased somewhat since then.

The 2MB includes all the programs and data you have loaded on your palmtop,
but if your prepared to mostly dedicated it to surveying, I don't think
memory would restrict processing.

Cheers,
Olly