KVN
Current Status of KJCC operationandUpgrade
Se-Jin Ohand staff of Correlator team of KASI/NAOJ

VERA User’s Meeting, 03~04 Oct. 2016, @ Mitaka, Japan

Contents
KJCC system status
 Problem(known) and others
Correlation Status
Recent Activities
Future WorkKJCC(Korea-Japan Correlation Center)

Executive Board

Daejeon HW Correlator

DiFX SW Correlator

KJCC system status[Known Problem, k16jm01b(r16153b)(J .Miller-san)]Cross-spectrum• Simultaneous obs(1G/8G) was done.
• When obs was started, DFB of KUS
setting was changed from 1G to 8G.
• Then KUS has strange band shape.

KYS

KTN

KUS

Auto-spectrum

VCS firmware upgradeTo support wideband correlation, Daejeon
correlator new firmware was installed.
 Full output speed of VCS is supported.
 2/4/6/8 Gbps correlation is optionallypossible for each obs mode.

Correlation Status
SeasonObservation

Corr
Finished

Remain Corr

FITS
release2016B

21(w/2 geo)

9107

2016A

103(w/5 geo)

97

197

http://kjcc.kasi.re.kr
http://kava.kasi.re.kr

Correlation Time Statistics
2016A

EA

Average days forcorr completion

Overall

103

52

ESTEMA(Imai)

1460

Hybrid (KVN re-corr)

Evolved Star(Hirota)

1076

Hybrid (KVN re-corr)

ES(Motogi)

444

AGN(Kino)

1349

AGN(Liu)

443

AGN(Koyama)

647

AGN(Ro)1346

AGN(Park, Oh)

2045

GA-sub251

ToO(JS Kim)

447

ToO(Miller)

358

Test(IljeCho,Sugiyama)

3C2 mode(short IP)

Others2

Dual-polGeodesy

5

Diskpack delivery

remarkPeriod means
each session final obs dateto fits release date~30

Only copy & delivery

13

OCTADISKRecent Activities[2Gbps test correlation of VSREC recoder] K16mk02m(r16144a)
 1G/2Gbps simultaneously recorded
 MIZ, ISH of 2Gbps were lost due to diskpack
problem.
 1G : OCTADISK(VERA)/Mark5B(KVN)• Normally fits released

 2G : VSREC(VERA)/Mark6(KVN) 2Gbps correlation by KJCC
 KJCC had already experienced the 2Gbps
correlation, but we found that strange features forcorrelation result were appeared and surprised.

Strange features of Corr.

IRK

OGA
OGA-KYS

OGA-KUS

KYS
KUS

OGA-KTNKTN

KYS-KUSVSREC bit-assign(reversed)
 Bit-assign
 Bit-assign of VSREC is reversed compared toOCTADISK as bellowing BYTE-SWAP Stream sequence : 1sample=2bitPositive

1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16

Byte-swap 4 3 2 1 8 7 6 5 12 11 10 9 16 15 14 13

OCTADISKVSREC

 No-information from VERA, we did 10-kinds of bitassign test.
 After correction of bit-assign, we got the fringe.

VSREC 2Gbps corr result

8Gbps by Daejeon correlator
 OCTAD, OCTADISK2 were installed at KYS with thehelp of NAOJ(Oyama-san).
 R16133b : KYS, MIZ, IRK, OGA
 Source : 3C279 @ 22 GHz
 4 wideband(512MHz BW x 4 IFs : 2048 MHz BW)
 2Gbps(1Gsps x 2 bits @ 512 MHz BW) x 4 IFs
 Correlation : After obs, MIZ SW-CORR was used for
confirming the result. Then VERA data was deleted
unfortunately.
 KYS data was only used for Daejeon hardware
correlator in order to just check the correlation
function of 8Gbps.

8Gbps Auto-corr

IF1

IF3

IF2

IF4

8Gbps Cross-corr(actually Auto)-1

IF1

IF2

8Gbps Cross-corr(actually Auto)-2IF3IF4

SW Digital Filtering by Yeom-san
In order to solve the different observation
mode such as 2Gbps(512MHz BW x 1IF) or1Gbps(32MHz BW x 8IFs), SW Digital Filtering
method was considered and developed.
Advantage : if VERA HW DFB has problem, it
will be helpful to process.
Disadvantage
 Current version is very slow. it needs to bemodified the algorithm for speed up.

R16144a(2Gbps  1Gbps) SW DF

IRK (IF 5)
Auto-corr

OGA (IF 5)
Auto-corr

For wideband correlation[Daejeon Correlator?]
 VCS specification
 Already designed and implemented for wideband(8Gbps)
 But the other equipment as playback terminal and output
saving system are also needed to be prepared.

1. The software for data splitting and upload to theRVDB are required.
2. The playing back of the RVDB with 8 Gbps
observation data to the VCS is needed.
3. 8Gbps correlation by the Daejeon correlator is alsoneeded according to the 4 VSI input.
4. CODA/FITS SW(Post processing SW) for correlated
result is also needed and improved.

Data Splitting and transmission SW
 KVN 8Gbps observation
 1024 Msps x 2bits x 4streams/station
 The obs data of 22, 43, 86 and 129 GHz frequency for theKVN multi-frequency simultaneous observing system iscombined with 4 data streams as time-ordered.
 Mark6, file system is combined with 8Gbps need to split
 Data Splitting SW development was finished and will betested

 VERA 8Gbps observation
 4 frequency like KVN is not supported, but 2 frequency(22/43, dual-beam) simultaneous obs mode are supported
 In this case, 22/43 LCP/RCP obs for KaVA will be used.
 OCTADISK2, file system is separated with 2Gbps each.

Data Upload to RVDB

Data Splitting & Transmission Basic8Gbps

IF1(512MHzBW), 2Gbps
IF2(512MHzBW), 2Gbps
IF3(512MHzBW), 2Gbps
IF4(512MHzBW), 2Gbps

IF1(512MHzBW), 2Gbps
IF2(512MHzBW), 2Gbps
IF3(512MHzBW), 2Gbps
IF4(512MHzBW), 2Gbps

DataSplitting SW Develop. was recently
finished
IF1(512MHz

8Gbps Playback

IF2(512MHzBW), 2Gbps

OCTADDB1

IF3(512MHzBW), 2Gbps

OCTADDB2BW), 2Gbps

IF4(512MHzBW), 2Gbps

DataTrans. SW

OCTADDB3

OCTADDB4New Archive System The maintenance service of current Archive system from Vender
will be terminated in this September 2016.
 For introduce new archive system, KASI searched for somevender(EMC, HP, DELL etc). And we also discussed with Elecs
industry for modifying OCTADISK2 to some storage system.
 Elecs proposed that OCTADISK2 is also some kind of storage andit is able to be modified storage. They could provide receiving
SW from VCS. The test performance experiments proposed VCS
Data Archive(VDA) is satisfied as VCS maximum output speed.
 By the Public Procurement Service(PPS), the competition wasfinished and made a contract with Elecs Industry(Metaspace). It
was installed in the end of August 2016.

New Data Archive System
VDA(VCS Data Archive) CPU : Intel ZEON, 32 cores
 Memory : 32GB
 Storage : 160TB(RAID 5, 6)
 Interface : 10GbE x 8 ea, SFP+(4 VCS, 4 External)
 10GbE x 4ea, 10GBASE-T (Gluster FileSystem)
 1GbE x 4ea, 1GBASE-T (Control) Access speed : Write : max 1.4GB/sec
 Read : max 2.2GB/sec

 Installed and tested
 Full speed(1.4GB/s) of VCS results aresaved

Italy-VERA data conversion
Help to data conversion of VERA
 Data bit-assign of VERA is different fromstandard Mark5B(Italy, KVN) KJCC developed many data handling SW
such as data conversion (mk5b to vdif, octavdif to std-vdif, vdif to mk5b, etc.)
 Test conversion of short VERA data wassuccessful. Now whole VERA data isconverting to deliver Italy for makecorrelation.

STARDOM server
 STARDOM server Over 2Gbps observation requests are quite frequent and2/8Gbps observation will be normally conducted soon.
 Data transfer from Mk6(or OCTADISK(2)) is needed to be
uploaded to RVDB.
 KJCC now prepared 2 data transfer server.
 2 more server will be introduced within this month for etransfer of KaVA

Future WorkFull 8Gbps correlation
 Currently 4 station is possible.
 For KaVA 7 or 8 stations, 4 RVDBs areneeded. For this issue, DM is now discussing
for modifying VCS data input part(change
VSI to VDIF)
CODA/FITS
 Support 4/6/8Gbps correlation
 Support for Dual-polarization
E-transfer test from VERA