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author | Joe Hunkeler <jhunkeler@gmail.com> | 2015-08-11 16:51:37 -0400 |
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committer | Joe Hunkeler <jhunkeler@gmail.com> | 2015-08-11 16:51:37 -0400 |
commit | 40e5a5811c6ffce9b0974e93cdd927cbcf60c157 (patch) | |
tree | 4464880c571602d54f6ae114729bf62a89518057 /unix/os/doc/zfiosf.hlp | |
download | iraf-osx-40e5a5811c6ffce9b0974e93cdd927cbcf60c157.tar.gz |
Repatch (from linux) of OSX IRAF
Diffstat (limited to 'unix/os/doc/zfiosf.hlp')
-rw-r--r-- | unix/os/doc/zfiosf.hlp | 51 |
1 files changed, 51 insertions, 0 deletions
diff --git a/unix/os/doc/zfiosf.hlp b/unix/os/doc/zfiosf.hlp new file mode 100644 index 00000000..e618031c --- /dev/null +++ b/unix/os/doc/zfiosf.hlp @@ -0,0 +1,51 @@ +.help zfiosf May84 "System Interface" +.ih +NAME +zfiosf -- static file driver +.ih +SYNOPSIS +.nf +zopnsf (osfn, mode, chan) # open static file +zclssf (chan, status) # close static file +zardsf (chan, buf, maxbytes, loffset) # asynchronous read +zawrsf (chan, buf, nbytes, loffset) # asynchronous write +zawtsf (chan, status) # wait for transfer +zsttsf (chan, param, lvalue) # get file/device status + +packed char osfn[] +char buf[] +int mode, chan, maxbytes, nbytes, param, status +long loffset, lvalue +.fi +.ih +DESCRIPTION +The static file driver is used to randomly access binary files which do not +change in size once created, hence the term static. Except where noted +herein, the specifications of the static file driver are equivalent to those +of the ordinary random access binary file driver. + +A static binary file is created by the kernel primitive \fBzfaloc\fR, +hence \fBzopnsf\fR cannot be used to create a new file (NEW_FILE mode is not +supported). The asynchronous read and write primitives behave conventionally +except that writing at EOF or overwriting EOF is not permitted. +.ih +NOTES +The static file driver should provide the lowest possible level of binary +file i/o for maximum efficiency. Since the file size is known at file creation +time it is often possible to allocate a contiguous file. Given a contiguous or +nearly contiguous file which does not change in size it is sometimes possible +to bypass the host files system once the file has been created, i.e., to +map the \fBzfiosf\fR primitives directly into calls to the disk driver on the +host machine. + +On a virtual memory machine it may also be possible to map the static file +into virtual memory, i.e., defer i/o until the file data is actually used. +If a virtual memory interface is implemented \fBzardsf\fR will remap pages +of memory, \fBzawrsf\fR will update pages of memory, \fBzawtsf\fR will do +nothing but return status, and \fBzclssf\fR will update and unmap any +mapped pages and close the file. See the reference manual for further +discussion of static file implementation strategies. +.ih +SEE ALSO +zfiobf, manual pages for the binary file driver +.endhelp |