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makelog - reconstruct an ERP log file from the raw file


makelog logfile [-n] [-f rawfile]


makelog is a program which allows one to recover a lost log file associated with a continuous data raw file. It creates the reconstructed log file logfile by reading the mark track from the raw file and transferring the relevant information. The raw file does not contain all the information needed to unambiguously reconstruct a log file, since the condition codes are not recorded in the raw file. Hence, it is also necessary to have a detailed record of the order of the condition codes and the points during the experiment where they changed; this information, in conjunction with the programs logpoke(1) or remapccs(1) , will allow the final stage of reconstruction.

During the course of an experiment, condition codes are altered while digitization is paused; whenever a pause occurs, a pause mark is placed in the log file. Whenever makelog encounters a pause or delete mark in the raw file, it increments the condition code in logfile. These "pseudo-condition codes" start at 64 (decimal) at the beginning of the raw file, and proceed upward. After makelog is done, one will have the logfile with "pseudo-condition codes" which need to be mapped by the experimenter into the appropriate values. The programs logpoke(1) or remapccs(1) can be used for this purpose; consult their man pages for details on how this is accomplished.

It should be noted that logfile may not contain events that occurred very near the end of the raw file, most noteably the final pause mark if the dig program was paused just before exiting. This is due to the fact that makelog uses the same low-level routines to read the raw file as other programs such as garv(1) and avg(1) : these programs purposefully ignore events in the last few records of the raw file to ensure that all events are followed by at least an epoch’s worth of raw data; the side-effect to makelog is that any events very near the end of the raw file will not be read and thus will not be present in the regenerated logfile.


Don’t rewind tape on exit. This option is a vestige of the days when raw files were recorded on magtape.

-f rawfile
Use the file rawfile instead of reading from the tape device (the default). This option is also a vestige of the magtape days, and since it will likely always be used now that raw files are recorded to disk it should really be a mandatory argument rather than an option.

See Also

logexam(1) , logpoke(1) , remapccs(1)

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