> My name is Soichiro Kuribayashi and I am a Ph.D. student at Kyoto University. 
> I'm a T2K collaborator and working for Super FGD which is new detector in ND280.

Hi! I did much of the DAQ software for the original FGD. I hope I can help.

> For the DAQ of Super FGD, we will run remotely front end part of MIDAS on ZYNQ 
> which is system on chip.

This would be the same as the existing FGD. Inside the FGD DCC is a Virtex4 FPGA
with a 300MHz PPC CPU running Linux from a CompactFlash card (Kentaro-san did this 
part). On this linux system runs the FGD DCC midas frontend. It connects
to the FGD midas instance using the mserver. This frontend executable is
copied to the DCC using "scp", there is no common nfs mounted home directory.

> For this remote control of front end part with mserver, we have to mount home 
> directory of DAQ PC(Cent OS8) on that of Linux on ZYNQ.
> So I wonder if we should use NFS(Network file system) + NIS(Network information 
> service) + autofs for the mounting. Is it correct?

Since you have a bigger SOC and you can run pretty much a complete linux,
I do recommend that you go this route. During development it is very convenient
to have common home directories on the main machine and on the frontend fpga
machines.

But this is not necessary. the midas mserver connection does not require
common (nfs-mounted) home directory, you can copy the files to the frontend
fpga using scp and rsync and you can use the gdb "remote debugger" function.

I can also suggest that on your frontend SOC/FPGA machine, you boot linux
using the "nfs-root" method. This way, the local flash memory only
contains a boot loader (and maybe the linux kernel image, depending on
bootloader limitations). The rest of the linux rootfs can be on your
central development machine. This way management of flash cards,
confusion with different contents of local flash and need to make backups
of frontend machines is much reduced.

If you use a fast SSD and ZFS with deduplication, you will also have good
performance gain (NFS over 1gige network to server with fast SSD works
so much better compared to the very slow SD/MMC/NAND flash).

I can point you to some of my documentation how we do this.

>
> If you have any information or any suggestion for the remote control on chip, 
> please let me know.
> 

I would say you are on a good track. For early development on just one board,
pretty much any way you do it will work, but once you start scaling up
beyound 3-4-5 frontends, you will start seeing benefits from common NFS-mounted
home directories, NFS-root booted linux, etc.

And of course you may want to study the existing ND280/FGD DAQ. I hope you
have access to the running system at Jparc. If not, I have a copy of
pretty much everything (except for running hardware, it is stored in the basement, 
dead) and I can give you access.

P.S. This reminds me that the cascade software from ND280 (they key part
for connecting the FGD, the TPC, the slow controls & etc into one experiment)
was never merged into the midas repository. I opened a ticket for this,
now we will not forget again:

https://bitbucket.org/tmidas/midas/issues/291/import-cascase-frontend-from-t2k-
nd280-fgd

K.O.