8 lines
3.3 KiB
Plaintext
8 lines
3.3 KiB
Plaintext
XEROX HostUp
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HostUp
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By: Johannes A. G. M. Koomen
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(Koomen.wbst@Xerox or Koomen@CS.Rochester.edu)
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This document last edited on December 27, 1988
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SUMMARY
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This module provides the function HOSTUP? which attempts to find out if a given host is currently available. Contrast this to the system function HOSTNAMEP, which returns T if it has at any time successfully opened a connection to given host, whether or not it is currently available.
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DETAILS
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(HOSTUP? hostname) [Function]
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Returns T if and only if the given host is currently responding. No distinction is made between dead and non-existing hosts.
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HOSTUP.TIMEOUT [Global variable]
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The function HOSTUP? returns NIL if no response is received from the given host within HOSTUP.TIMEOUT milliseconds. Default value is 15,000.
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HOSTUP.RETRYCNT [Global variable]
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This variable indicates the number of times the function HOSTUP? sends requests to the given host. Each time through the loop the function waits longer by a geometrically increasing amount if time, such that the total time does not exceed HOSTUP.TIMEOUT. Default value is 5. Hence, in the default case, a call to HOSTUP? with a dead host ends up sending a request to the host 5 times, waiting for an answer about 500, 1000. 2000. 4000 and 8000 milliseconds, respectively.
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(LIST ((PAGE NIL (FOLIOINFO (ARABIC) STARTINGPAGE# 1) (0 0 612 792) ((FOLIO NIL (PARALOOKS (QUAD CENTERED) CHARLOOKS (SUPERSCRIPT 0 SIZE 10 FAMILY MODERN OVERLINE OFF STRIKEOUT OFF UNDERLINE OFF SLOPE REGULAR WEIGHT MEDIUM) FORMATINFO (ARABIC)) (174 36 288 36) NIL) (HEADING NIL (HEADINGTYPE RUNNINGHEAD) (84 744 444 36) NIL) (TEXT NIL NIL (84 96 456 600) NIL))) (PAGE NIL NIL (0 0 612 792) ((FOLIO NIL (PARALOOKS (QUAD CENTERED) CHARLOOKS (SUPERSCRIPT 0 SIZE 10 FAMILY MODERN OVERLINE OFF STRIKEOUT OFF UNDERLINE OFF SLOPE REGULAR WEIGHT MEDIUM)) (282 42 72 36) NIL) (HEADING NIL (HEADINGTYPE RUNNINGHEAD) (84 744 444 36) NIL) (TEXT NIL NIL (84 96 456 600) NIL))) (PAGE NIL NIL (0 0 612 792) ((FOLIO NIL (PARALOOKS (QUAD CENTERED) CHARLOOKS (SUPERSCRIPT 0 SIZE 10 FAMILY MODERN OVERLINE OFF STRIKEOUT OFF UNDERLINE OFF SLOPE REGULAR WEIGHT MEDIUM)) (282 42 72 36) NIL) (HEADING NIL (HEADINGTYPE RUNNINGHEAD) (84 744 444 36) NIL) (TEXT NIL NIL (84 96 456 600) NIL))))) 1 <01> <01> ( <01> . <01> <01> ( <01> ( <00> <00>8 ( <00> <00>8 D <01> <01> PAGEHEADING RUNNINGHEAD HELVETICA
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MODERN
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MODERN
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MODERN
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MODERN MODERN LOGO HRULE.GETFN MODERN
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HRULE.GETFN MODERN
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HRULE.GETFN MODERN
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HRULE.GETFN MODERN HRULE.GETFN MODERN O 0 <00> [ ~ <00> <01> 6z<36> |