Thanks for that, Jason! It is very timely. The reason I went down this
path is because I have a spectrometer design, by Joseph Trinh, which
takes a slightly different approach to bram access and so I could not
use the katcp_wrapper which I'd been using with your 16K spectrometer.
He'd offered to modify it but I thought it cool to try the file access
I/O. I think as a result of this exchange, I'll ask Joseph to modify
his design and I'll start using pyro.
I hope he can squeeze it into a ROACH-1. He's got a 2x1024 spectrometer
design for me now but had to drop the PFBs because of insufficient
resources. I'm asking him to try 2x512 with PFBs. Does anyone already
have something like that?
Next time around we'll use ROACH-2 but at the time we placed the orders
we weren't sure that the support for that would evolve fast enough to
meet our deadline (next month).
Cheers
Tom
On 08/29/2012 01:09 AM, Jason Manley wrote:
On 29 Aug 2012, at 02:44, Adam Barta wrote:
You could also try an ssh port forward to the katcp port ssh -vNL
7147:roach:7147 gateway
Then use the katcp interface to read / write the registers. There is a
katcp_wrapper.py in the corr library
I would like to re-inforce this suggestion if you need SSH tunnelling through a
firewall. A general word of warning to the CASPER community, which we also
explained at the recent workshop...
MeerKAT will not be supporting filesystem-level access in future boards (quite
possibly starting with ROACH-2 already) and so, unless someone else in the
collaboration picks it up, you'll be on your own if you write custom software
to run on the PPC/BORPH because new platforms might not even run BORPH at all.
There are a number of reasons for this decision, one being that we've run into
performance limitations with BORPH, but also that it's a big overhead to port
and debug and to keep it running reliably.
The only interface supported by SKA-SA will be through KATCP. So if you start
using the KATCP interface now, you'll have a transparent upgrade path to future
boards. I'd suggest you don't worry yourself too much with the low-level
detail... this is part of what CASPER tries to abstract away to ease your life
as an instrument designer.
If you don't want to write your own KATCP interface (and who does?!), consider
using one of the existing ones. The best developed ones are in c (which
includes a command-line executable for a single-line, ipython-like interactive
experience from the shell prompt if you just want to call a shell script with a
bunch of commands), available at https://github.com/ska-sa/katcp_devel, or a
number of CASPER collaborators are using the python wrapper from corr if you
want to build a higher-level GUI application. You can find a one-page getting
started guide here: https://casper.berkeley.edu/wiki/Corr
Jason
--
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