AO scramnet

29aug2004

    Scramnet is a reflective memory system consisting of nodes (sbus,vmebus cards) connnected in a ring configuration via fiber optics. Each node contains memory (128kb in our case). When any node writes into its memory, the information is propagated around the ring so it appears in the same memory location in all the other nodes on the ring. Ring transfer rates are 5 to 12mb/sec
    . The data acquisition system at AO uses scramnet to pass information between 3 vme crates (pnt,da,cor) and 2 sun workstations (observer,control). The memory is broken into different blocks. Each block holds status information about a particular device or function. The observer workstation takes the data from scramnet memory and places the data in a shared memory block.

     The use of "scramnet" was extended at a later time:

The data from the reflective memory is placed in shared memory on the observer workstation.
A program (multiexec) takes some of the blocks from shared memory and multicasts them out the ethernet.
3 other programs (cima exec shared memory, alfa monitoring and position, wapp info) take various blocks of information and multicast them out the local ethernet.
All of these broadcast packets are now called "scramnet info".

Blocks that originate from reflective memory:

The reflective memory broadcast blocks are defined as C structures.
disc locations:

/home/phil/vw/devs/scrm/scrmLoad.h - defines the blocks that make up reflective memory
/home/phil/vw/h/scrmBlkXXX.h defines an individual scramnet block. Usually just contains a single structure definition.

eg pntProgState.h

Blocks that go through reflective memory
block	Struct defined in /home/phil/vw/h	DataSrc	Notes
pointing	pntProgState.h	vme pnt	pointing info, ra, dec,etc
vertex (az,ch,gr)	agcProgState.h	vme pntp1	az,dome,ch device info. actual encoders, state,etc.
turret	ttProgState.h	vme pntp2	rotary floor info
tiedowns	tieProgState.h	vne pntp3	tiedown info
Downstairs iflo (IF2)	if2ProgState.h	vme da	synths, power, switches for downstairs if/lo
Upstairs iflo (IF1)	if1ProgState.h	vme da	synths, power, switches for upstairs if/lo
Doppler correction (vxWorks only)	dopState.h		not loaded
pattern procedure info	procState.h		not loaded
planetary radar info	plrdrState.h	pntp3	not yet loaded
sb723 trransmitter info	sb723State.h	pntp3	not yet loaded?
tertiary			not used
Blocks that originate from a program
block	Struct def:	DataSRc	Notes
Cima executive info	execshm.h	observer2	Only runs when cima gui is active. Holds experiment setup info: projid, etc.. see multiexec
alfa monitoring and motor position	alfashm.h	aeroncpu	see alfa_mon
Wapp dataking info	wappshm.h	wapp	see multiwapp

Notes:

multiexec.c - multicast broadcast of cima execuitve info

Source: /home/cima/Wapp/Software/Svnwork/Sources/Tools_linux/
includeFile: /home/cima/Wapp/Software/Svnwork/Includes/execshm.h
Only runs while cima gui is running

alfa_mon.c - multicast alfa dewar temps as well as alfa motor position (which it gets from alfa_mot.c).

Source:/home/cima/Wapp/Software/Svnwork/Sources/Utilities/
Include: /home/cima/Wapp/Software/Svnwork/Sources/Includes/alfashm.h

multiwapp.c - multicast wapp observation data.

Source: /home/cima/Wapp/Software/Svnwork/Sources/Wapp
include: /home/cima/Wapp/Software/Svnwork/Sources/Includes/wappshm.h

scramShm.c - grabs multicast packets for all blocks and places them in shared memory (phil's version).

The shared memory is configured for the mock spectrometers. The general idea of grabbing the blocks is here.
source:/share/megs/phil/svn/pdev/pdev/datatk
Uses libbp (buffer pool library,). libphil ( bunch of utility routines).

scramshm.c - grab multicast packets for agc or pnt and place in local shared memory (jeff hagens version).

Old writeup on the structure of reflective memory scramnet used at ao (.ps)

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