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The ATNF-Parkes-Swinburne Recorder (APSR)

Willem van Straten Andrew Jameson and Matthew Bailes Centre for Astrophysics and Supercomputing Swinburne University of Technology

Grant Hampson and Dick Manchester The Australia Telescope National Facility
Second ATNF Gravitational Wave Workshop 13 December 2007


Outline

· Baseband Recording and Processing Systems · Hardware Specification · Software Design and Implementation · National Facility Instrument Management

Second ATNF Gravitational Wave Workshop

13 December 2007


Baseband Recording and Offline Pro cessing

· VLBI tape recorders (S2 and Mark4) ­ 5 - 16 MHz of bandwidth ­ offline playback and processing ­ specialized playback hardware · Commercial tape recorders (CBR and CPSR) ­ 10 - 20 MHz of bandwidth ­ offline playback and processing ­ off-the-shelf playback hardware, including tape robot

Second ATNF Gravitational Wave Workshop

13 December 2007


Baseband Recording and Online Pro cessing

· Disk-based recording (CPSR2 and PuMa-II) ­ 128 - 160 MHz of bandwidth ­ near real-time processing ­ SCSI and/or RAID required · Real-time processing (ASP and APSR) ­ 32 - 1024 MHz of bandwidth ­ real-time processing directly from RAM ­ no DMA or RAID required

Second ATNF Gravitational Wave Workshop

13 December 2007


Advantages of Data Reduction in Software
· less engineering time = more experimentation time · phase-coherent dedispersion · processing multiple pulsars in globular cluster observations · correcting digitization artifacts; e.g. dynamic output level setting · Nyquist limited phase and frequency resolution · pulse phase-locked filterbank formation high frequency resolution dynamic spectra · future: virtual phase conjugation ?
Second ATNF Gravitational Wave Workshop 13 December 2007


APSR Hardware Sp ecification

· DFB3 - digitizer and polyphase filterbank; output UDP on 4 x CX4 · 2 x 10GbE to Cisco 3750 switch · 16 x 1GbE to cluster · 20 x Dell PowerEdge 1950 ­ dual-quad core Clovertown processors ­ 16 G B R A M ­ 2 x 50 GB drives

Second ATNF Gravitational Wave Workshop

13 December 2007


APSR Software Design Goals
· modular: ­ small, simple, single-purpose processes ­ inter-process communication: synchronization and coordination · extensible: ­ well-defined interface to ring buffer in shared memory ­ various read/write clients developed using interface library · usable: ­ single user interface launches and controls all processes ­ configuration scripts enable mode selection and customization

Second ATNF Gravitational Wave Workshop

13 December 2007


APSR Software Implementation

· data acquisition and transfer code written in C (psrdada) · high-level control and configuration scripts written in Perl · TCS interface written in Perl · user interface implemented using Java script · data reduction software written in C++ (dspsr) · data analysis and archival written in C++ (psrchive)
Second ATNF Gravitational Wave Workshop 13 December 2007


APSR Software Implementation: Details

· data acquisition processes synchronized using semaphores · command and control via text-based socket interfaces · user interface through web browser (incl. ganglia) · multi-threaded data reduction exploits multi-core architectures

Second ATNF Gravitational Wave Workshop

13 December 2007


A National Facility Instrument

· APSR cluster administered by Swinburne supercomputing staff · software and data products stored on mirrored servers · ATCS-style software version control · extensive online documentation · well-defined data and resource management policy; e.g. ­ group ID for each project; data belong to group ­ batch queue system for CPU and disk usage
Second ATNF Gravitational Wave Workshop 13 December 2007