+.NH 2
+/sys/h
+.PP
+Files residing here are intended to be machine independent.
+Consequently, the header files for device drivers which
+were present in this directory in 4.1BSD have been moved
+to other directories;
+e.g. /sys/vaxuba. Many files which had been duplicated in
+/usr/include are now present only in /sys/h. Further, the
+4.1BSD /usr/include/sys directory is now normally a symbolic link
+to this directory. By having only a single copy of these files
+the ``multiple update'' problem no longer occurs. (It is still
+possible to have /usr/include/sys be a copy of the /sys/h for
+sites where it is not feasible to allow the general user
+community access to the system source code.)
+.PP
+The following files are new to /sys/h in 4.2BSD:
+.IP \fBdomain.h\fP 15
+describes the internal structure of a communications domain; part of
+the new ipc facilities
+.IP \fBerrno.h\fP 15
+had previously been only in /usr/include; the file /usr/include/errno.h
+is now a symbolic link to this file
+.IP \fBfs.h\fP 15
+replaces the old filsys.h description of the file system organization
+.IP \fBgprof.h\fP 15
+describes various data structures used in profiling the
+kernel; see \fIgprof\fP\|(1) for details
+.IP \fBkernel.h\fP 15
+is an offshoot of systm.h and param.h; contains constants and
+definitions related to the logical UNIX ``kernel''
+.IP \fBmbuf.h\fP 15
+describes the memory managment support used mostly by the network;
+see ``4.2BSD Networking Implementation Notes'' for more information
+.IP \fBmman.h\fP 15
+contains definitions for planned changes to the memory management
+facilities (not implemented in 4.2BSD)
+.IP \fBnami.h\fP 15
+defines various structures and manifest constants used in
+conjunctions with the \fInamei\fP routine (part of this file
+reflects future plans for changes to \fInamei\fP rather
+than current use)
+.IP \fBprotosw.h\fP 15
+contains a description of the protocol switch table and related
+manifest constants and data structures use in communicating with
+routines located in the table
+.IP \fBquota.h\fP 15
+contains definitions related to the new disk quota facilities
+.IP \fBresource.h\fP 15
+contains definitions used in the \fIgetrusage\fP,
+\fIgetrlimit\fP, and \fIgetpriority\fP system calls (among others)
+.IP \fBsocket.h\fP 15
+contains user-visible definitions related to the new socket ipc
+facilities
+.IP \fBsocketvar.h\fP 15
+contains implementation definitions for the socket ipc facilities
+.IP \fBttychars.h\fP 15
+contains definitions related to tty character handling; in particular,
+manifest constants for the system standard erase, kill, interrupt,
+quit, etc. characters are stored here (all the appropriate user
+programs use these manifest definitions)
+.IP \fBttydev.h\fP 15
+contains definitions related to hardware specific portions of tty
+handling (such as baud rates); to be expanded in the future
+.IP \fBuio.h\fP 15
+contains definitions for users wishing to use the new
+scatter-gather i/o facilities; also contains the kernel \fIuio\fP
+structure used in implementing scatter-gather i/o
+.IP \fBun.h\fP 15
+contains user-visible definitions related to the ``unix'' ipc domain
+.IP \fBunpcb.h\fP 15
+contains the definition of the protocol control block used
+in the ``unix'' ipc domain
+.IP \fBwait.h\fP 15
+contains definitions used in the \fIwait\fP and \fIwait3\fP\|(2)
+system calls; previously in /usr/include/wait.h
+.PP
+The following files have undergone significant change:
+.IP \fBbuf.h\fP 15
+reflects the changes made to the buffer cache for the
+new file system organization \- buffers
+are variable sized with pages allocated to buffers on
+demand from a pool of pages dedicated to the buffer cache;
+one new structure member has been added
+to eliminate overloading of a commonly unreferenced structure
+member; a new flag B_CALL, when set, causes the function
+\fIb_iodone\fP to be called when i/o completes on a buffer
+(this is used to wakeup the pageout daemon); macros have
+been added for manipulating the buffer queues, these replace
+the previous subroutines used to insert and delete buffers
+from the queues
+.IP \fBconf.h\fP 15
+reflects changes made in the handling of swap space and
+changes made for the new \fIselect\fP\|(2) system call;
+the block device table
+has a new member, \fId_psize\fP,
+which returns the size of a disk partition, in sectors,
+given a major/minor value; the character device table has a
+new member, \fId_select\fP, which is passed
+a \fIdev_t\fP value and an FREAD (FWRITE) flag and returns
+1 when data may be read (written), and 0 otherwise; the
+\fIswdevt\fP structure now includes the size, in sectors,
+of a swap partition
+.IP \fBdir.h\fP 15
+is completely different since directory entries are now
+variable length; definitions for the user level interface
+routines described in \fIdirectory\fP\|(3) are also present
+.IP \fBfile.h\fP 15
+has a very different \fIfile\fP structure definition and
+definitions for the new \fIopen\fP and \fIflock\fP system
+calls; symbolic definitions for many constants commonly
+supplied to \fIaccess\fP and \fIlseek\fP, are also present
+.IP \fBinode.h\fP 15
+reflects the new hashed cacheing scheme as well additions
+made to the on-disk and in-core inodes; on-disk inodes
+now contain a count of the actual number of disk
+blocks allocated a file (used mostly by the disk quota
+facilities), larger time stamps (for planned changes),
+more direct block pointers, and room for future growth;
+in-core inodes have new fields for the advisory locking
+facilities, a back pointer to the file system super block
+information (to eliminate lookups), and a pointer to
+a structure used in implementing disk quotas.
+.IP \fBioctl.h\fP 15
+has all request codes constructed from _IO, _IOR,
+_IOW, and _IOWR macros which encode whether the request
+requires data copied in, out, or in and out of the kernel
+address space; the size of the data parameter (in bytes) is
+also encoded in the request, allowing the \fIioctl\fP\|()
+routine to perform all user-kernel address space copies
+.IP \fBmount.h\fP 15
+the \fImount\fP structure has a new member used in
+the disk quota facilities
+.IP \fBparam.h\fP 15
+has had numerous items deleted from it; in
+particular, many definitions logically part of the ``kernel''
+have been moved to kernel.h, and machine-dependent values and
+definitions are now found in param.h files located in
+machine/param.h; contains a manifest constant, NGROUPS,
+which defines the maximum size of the group access list
+.IP \fBproc.h\fP 15
+has changed extensively as a result of the new signals, the
+different resource usage structure, the disk quotas,
+and the new timers; in addition, new members are present
+to simplify searching the process tree for siblings; the
+SDLYU and SDETACH bits are gone, the former is replaced
+by a second parameter to \fIpagein\fP, the latter is no
+longer needed due to changes in the handling of open's
+on /dev/tty by processes which have had their controlling
+terminal revoked with \fIvhangup\fP
+.IP \fBsignal.h\fP 15
+reflects the new signal facilities; several new signals
+have been added: SIGIO for signal driven i/o; SIGURG for
+notification when an urgent condition arises; and SIGPROF and
+SIGVTALRM for the new timer facilities; structures used
+in the \fIsigvec\fP\|(2) and \fIsigstack\fP\|(2) system
+calls, as well as signal handler invocations are defined
+here
+.IP \fBstat.h\fP 15
+has been updated to reflect the changes to the inode
+structure; in addition a new field \fIst_blksize\fP
+contains an ``optimal blocking factor'' for performing
+i/o (for files this is the block size of the underlying
+file system)
+.IP \fBsystm.h\fP 15
+has been trimmed back a bit as various items were moved
+to kernel.h
+.IP \fBtime.h\fP 15
+contains the definitions for the new time and interval
+timer facilities; time zone definitions for the half dozen
+time zones understood by the system are also included here
+.IP \fBtty.h\fP 15
+reflects changes made to the internal structure of the
+terminal handler; the ``local'' structures have been
+merged into the standard flags and character definitions
+though the user interface is virtually identical to that
+of 4.1BSD; the TTYHOG value has been changed from 256 to
+255 to account for a counting problem in the terminal
+handler on input buffer overflow
+.IP \fBuser.h\fP 15
+has been extensively modified; members have been grouped
+and categorized to reflect the ``4.2BSD System Manual''
+presentation; new members have been added and existing members
+changed to reflect: the new groups facilities,
+changes to resource accounting and limiting, new timer facilities,
+and new signal facilities
+.IP \fBvmmac.h\fP 15
+has had many macro definitions changed to eliminate
+assumptions about the hardware virtual memory support;
+in particular, the stack and user area page table
+maps are no longer assumed to be adjacent or
+mapped by a single page table base register
+.IP \fBvmparam.h\fP 15
+now includes machine-dependent definitions from a file
+machine/vmparam.h.
+.IP \fBvmsystm.h\fP 15
+has had several machine-dependent definitions moved
+to machine/vmparam.h
projects / unix-history / commitdiff