1 files changed, 126 insertions, 0 deletions
diff --git a/unix/os/zfiosf.c b/unix/os/zfiosf.c
new file mode 100644
index 00000000..a6efe7ed
--- /dev/null
+++ b/unix/os/zfiosf.c
@@ -0,0 +1,126 @@
+/* Copyright(c) 1986 Association of Universities for Research in Astronomy Inc.
+ */
+
+#include <stdio.h>
+
+#define	import_kernel
+#define	import_knames
+#define import_spp
+#include <iraf.h>
+
+/*
+ * ZFIOSF -- Static file device driver.  In the 4.1BSD UNIX kernel the ordinary
+ * binary file driver is used for static files (files that do not change in
+ * size once created by ZFALOC), hence all we need do to implement a SF routine
+ * is call the corresponding BF routine.  A great gain in i/o efficiency could 
+ * probably be gained by replacing this driver by one using raw i/o, but we do
+ * not want to bother with that for 4.1BSD UNIX because the time would be
+ * better spent doing it for 4.2BSD.
+ *
+ * If anyone is stuck with 4.1BSD for some reason and wants fast static file
+ * i/o, the strategy is to try to allocate contiguous files with ZFALOC, either
+ * in a raw partition using a special file manager or within an ordinary
+ * partition adding a new system call to allocate contiguous storage for a file.
+ * The latter scheme has the advantage that files thus created are ordinary
+ * UNIX files and can be accessed normally as well as by the static file driver.
+ * Given a contiguous or near-contiguous file on disk, all the static file
+ * driver needs for direct access with large transfers is the physical block
+ * offset of the file.  The raw device is then accessed via physio calls to
+ * transfer data directly to or from the user's buffer, bypassing the system
+ * buffer cache.  Write perm is required on the raw device for the target
+ * filesystem; this opens up the possibility of trashing the files system.
+ * Static file access should be restricted to one or more large temporary files
+ * systems.  If one gets really ambitious a special UNIX driver can be added to
+ * permit asynchronous i/o, bypassing the UNIX files system entirely except
+ * during file creation and deletion.
+ */
+
+extern int  ZOPNBF(), ZCLSBF (), ZARDBF (), ZAWRBF (), ZAWTBF (), ZSTTBF ();
+
+
+/* ZOPNSF -- Open a static file.  Only RO, WO, and RW modes are permitted
+ * for static files, since allocation is via ZFALOC and appending is not
+ * permitted.
+ */
+int
+ZOPNSF (
+  PKCHAR  *osfn,			/* UNIX name of file		*/
+  XINT	  *mode,			/* file access mode		*/
+  XINT	  *chan 			/* file number (output)		*/
+)
+{
+	switch (*mode) {
+	case READ_ONLY:
+	case WRITE_ONLY:
+	case READ_WRITE:
+	    return ZOPNBF (osfn, mode, chan);
+	    break;
+	default:
+	    *chan = XERR;
+	    return (*chan);
+	}
+}
+
+
+/* ZCLSSF -- Close a static file.
+ */
+int
+ZCLSSF (XINT *fd, XINT *status)
+{
+	return ZCLSBF (fd, status);
+}
+
+
+/* ZARDSF -- "Asynchronous" static block read.  Initiate a read of at most
+ * maxbytes bytes from the file FD into the buffer BUF.  Status is returned
+ * in a subsequent call to ZAWTSF.
+ */
+int
+ZARDSF (
+  XINT	*chan,			/* UNIX file number			*/
+  XCHAR	*buf,			/* output buffer			*/
+  XINT	*maxbytes,		/* max bytes to read			*/
+  XLONG	*offset 		/* 1-indexed file offset to read at	*/
+)
+{
+	return ZARDBF (chan, buf, maxbytes, offset);
+}
+
+
+/* ZAWRSF -- "Asynchronous" static block write.  Initiate a write of exactly
+ * nbytes bytes from the buffer BUF to the file FD.  Status is returned in a
+ * subsequent call to ZAWTSF.
+ */
+int
+ZAWRSF (
+  XINT	*chan,			/* UNIX file number		*/
+  XCHAR	*buf,			/* buffer containing data	*/
+  XINT	*nbytes,		/* nbytes to be written		*/
+  XLONG	*offset 		/* 1-indexed file offset	*/
+)
+{
+	return ZAWRBF (chan, buf, nbytes, offset);
+}
+
+
+/* ZAWTSF -- "Wait" for an "asynchronous" read or write to complete, and
+ * return the number of bytes read or written, or ERR.
+ */
+int
+ZAWTSF (XINT *fd, XINT *status)
+{
+	return ZAWTBF (fd, status);
+}
+
+
+/* ZSTTSF -- Return status on a static file.
+ */
+int
+ZSTTSF (
+  XINT	*fd,
+  XINT	*param,
+  XLONG	*lvalue
+)
+{
+	return ZSTTBF (fd, param, lvalue);
+}