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I doubt that very much. AIPS has limits as distributed of 90 antennas and 90 IFs. The arrays for processing allow all of the baselines from this and there is no limit on the number of visibilities (I have been working on a data set with over 7000000 visibilities,
The limit on number of spectral channels times number of IFs is 132096. I don't have any idea about what is causing your issues. You might try the verb SETMAXAP which may have a smaller limit than required.</div>
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Eric</div>
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<b>From:</b> mz <mgnahz@gmail.com><br>
<b>Sent:</b> Monday, July 13, 2026 5:16 AM<br>
<b>To:</b> Eric Greisen <egreisen@nrao.edu><br>
<b>Subject:</b> Re: LUN/IO failure {External}</div>
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<div style="direction: ltr;">Dear Eric,</div>
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<div style="direction: ltr;">After several random tests, I found that the LUN/IO problem was caused by AIPS reaching its resource limits. </div>
<div style="direction: ltr;">For example, my original uv-data has 561571 visibilities:</div>
<div style="direction: ltr;">AIPS 3: Got(1) disk= 1 user= 15 type=UV MULTI.MSORT.1<br>
AIPS 3: Image=MULTI (UV) Filename=MULTI .MSORT . 1<br>
AIPS 3: # visibilities 561571 Sort order TB<br>
AIPS 3: --------------------------------------------------------------<br>
AIPS 3: Type Pixels Coord value at Pixel Coord incr Rotat<br>
AIPS 3: COMPLEX 3 1.000000E+00 1 1.0000E+00 0.00<br>
AIPS 3: STOKES 1 RR 1 -1.0000 0.00<br>
AIPS 3: FREQ 64 2.226053E+09 1* 2.5000E+05 0.00<br>
AIPS 3: IF 16 1.000000E+00 1 1.0000E+00 0.00<br>
AIPS 3: RA 1 00 00 00.000 1 0.000000 0.00<br>
AIPS 3: DEC 1 00 00 00.000 1 0.000000 0.00<br>
AIPS 3: --------------------------------------------------------------<br>
AIPS 3: Max ext file #: HI 1 AT 1 IM 1 CT 1 MC 1<br>
AIPS 3: Max ext file #: PC 1 FQ 1 AN 1 SU 1 CQ 1<br>
AIPS 3: Max ext file #: GC 1 NX 1 TY 1 SN 1 CL 4</div>
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<div style="direction: ltr;"> I tried to use AVSPC to average the channels within IFs and the number of visibilites reduced to 392374:</div>
<div style="direction: ltr;">AIPS 3: Image=MULTI (UV) Filename=MULTI .CH.0 . 1<br>
AIPS 3: # visibilities 392374 Sort order TB<br>
AIPS 3: --------------------------------------------------------------<br>
AIPS 3: Type Pixels Coord value at Pixel Coord incr Rotat<br>
AIPS 3: COMPLEX 3 1.000000E+00 1 1.0000E+00 0.00<br>
AIPS 3: STOKES 1 RR 1 -1.0000 0.00<br>
AIPS 3: FREQ 1 2.233927E+09 1* 1.2000E+07 0.00<br>
AIPS 3: IF 16 1.000000E+00 1 1.0000E+00 0.00<br>
AIPS 3: RA 1 00 00 00.000 1 0.000000 0.00<br>
AIPS 3: DEC 1 00 00 00.000 1 0.000000 0.00<br>
AIPS 3: --------------------------------------------------------------<br>
AIPS 3: Max ext file #: NX 1 HI 1 AT 1 CT 1 FQ 1<br>
AIPS 3: Max ext file #: AN 1 CL 4 CQ 1 GC 1 IM 1<br>
AIPS 3: Max ext file #: MC 1 PC 1 SN 2 SU 1 TY 1</div>
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<div style="direction: ltr;">After that, the FRING was happy to fit the data without any LUN/IO complaints. So I am asking: what are the undocumented limits of AIPS on the number of antennas, baselines, visibilites, etc? is there any way to modify them? With
regard to my data, I think it is not optimal to average the data either in spectral, temporal, polarizational domain, before frange fitting. So is there any way to partition the data into smaller pieces based on the source set with some AIPS tasks?</div>
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<div style="direction: ltr;">Best regards,</div>
<div style="direction: ltr;">Ming</div>
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<div style="direction: ltr;">On Sun, 12 Jul 2026 at 01:10, Eric Greisen <<a href="mailto:egreisen@nrao.edu" id="OWAdc33d65f-1bd5-c79d-b4c5-fcafa8ce7cff" class="OWAAutoLink">egreisen@nrao.edu</a>> wrote:</div>
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I have no idea. Sometimes a message file gets corrupted and that may be behind this. Go to your first data area and delete the MS file for your user number (or all of them is usually ok). Then start aips again.</div>
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Eric</div>
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<b>From:</b> mz <<a href="mailto:mgnahz@gmail.com" id="OWA2bda06dd-9739-f5e4-cf41-afde51cc6816" class="OWAAutoLink">mgnahz@gmail.com</a>><br>
<b>Sent:</b> Saturday, July 11, 2026 6:28 AM<br>
<b>To:</b> Eric Greisen <<a href="mailto:egreisen@nrao.edu" id="OWAf0ebb506-aa2e-a154-2e59-e5148d688a5f" class="OWAAutoLink">egreisen@nrao.edu</a>><br>
<b>Subject:</b> LUN/IO failure {External}</div>
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<div style="direction: ltr;">Dear Eric,</div>
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<div style="direction: ltr;">Thank you very much for your tip on creating a raw CL table using INDXR last time. Today, when I tried to perform a FRING fit, I obtained a dump of a series of LUN/IO faults, as shown below.</div>
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<div style="direction: ltr;">ZMSGDK: LUN = 12 NOT OPEN IN FTAB<br>
ZTTYIO: LUN = 6 NOT OPEN IN FTAB<br>
ZMSGCL: LUN = 12 ALREADY CLOSED IN FTAB ON SEARCH<br>
ZTTYIO: LUN = 6 NOT OPEN IN FTAB<br>
ZMSGCL: LUN = 6 ALREADY CLOSED IN FTAB ON SEARCH<br>
ZMSGDK: LUN = 12 NOT OPEN IN FTAB<br>
ZTTYIO: LUN = 6 NOT OPEN IN FTAB<br>
ZMSGCL: LUN = 12 ALREADY CLOSED IN FTAB ON SEARCH<br>
ZTTYIO: LUN = 6 NOT OPEN IN FTAB<br>
ZMSGCL: LUN = 6 ALREADY CLOSED IN FTAB ON SEARCH<br>
ZMSGDK: LUN = 12 NOT OPEN IN FTAB<br>
ZTTYIO: LUN = 6 NOT OPEN IN FTAB<br>
ZMSGCL: LUN = 12 ALREADY CLOSED IN FTAB ON SEARCH<br>
ZTTYIO: LUN = 6 NOT OPEN IN FTAB<br>
ZMSGCL: LUN = 6 ALREADY CLOSED IN FTAB ON SEARCH<br>
ZMSGDK: LUN = 12 NOT OPEN IN FTAB<br>
ZTTYIO: LUN = 6 NOT OPEN IN FTAB<br>
ZMSGCL: LUN = 12 ALREADY CLOSED IN FTAB ON SEARCH<br>
ZTTYIO: LUN = 6 NOT OPEN IN FTAB<br>
ZMSGCL: LUN = 6 ALREADY CLOSED IN FTAB ON SEARCH<br>
ZMSGDK: LUN = 12 NOT OPEN IN FTAB<br>
ZTTYIO: LUN = 6 NOT OPEN IN FTAB<br>
ZMSGCL: LUN = 12 ALREADY CLOSED IN FTAB ON SEARCH<br>
ZTTYIO: LUN = 6 NOT OPEN IN FTAB<br>
ZMSGCL: LUN = 6 ALREADY CLOSED IN FTAB ON SEARCH<br>
ZMSGDK: LUN = 12 NOT OPEN IN FTAB<br>
ZTTYIO: LUN = 6 NOT OPEN IN FTAB<br>
ZMSGCL: LUN = 12 ALREADY CLOSED IN FTAB ON SEARCH<br>
ZTTYIO: LUN = 6 NOT OPEN IN FTAB<br>
ZMSGCL: LUN = 6 ALREADY CLOSED IN FTAB ON SEARCH<br>
ZMSGDK: LUN = 12 NOT OPEN IN FTAB<br>
ZTTYIO: LUN = 6 NOT OPEN IN FTAB<br>
ZMSGCL: LUN = 12 ALREADY CLOSED IN FTAB ON SEARCH<br>
ZTTYIO: LUN = 6 NOT OPEN IN FTAB<br>
ZMSGCL: LUN = 6 ALREADY CLOSED IN FTAB ON SEARCH<br>
ZMSGDK: LUN = 12 NOT OPEN IN FTAB</div>
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<div style="direction: ltr;">I had to press Ctrl+C to close the MSGSRV term before I could return to the AIPS prompt then. Please enlighten me what problem I have encountered and how to handle this. Cheers!</div>
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<div style="direction: ltr;">Best regards,</div>
<div style="direction: ltr;">Ming</div>
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