The Base Operating System constants and control block structure definitions are contained in header files in the /usr/include and /usr/include/sys directories. The following are the major constants and control blocks and their corresponding header files:
| Item | Description | 
|---|---|
| /usr/include/a.out.h | Common Object File Format (COFF) structures | 
| /usr/include/core.h | An include file for the /usr/include/sys/core.h header file | 
| /usr/include/errno.h | An include file for the /usr/include/sys/errno.h header file | 
| /usr/include/lvmrec.h | LVM record structure | 
| /usr/include/sgtty.h | Line discipline structures and constants for Berkeley compatibility | 
| /usr/include/signal.h | An include file for the /usr/include/sys/signal.h header file | 
| /usr/include/termio.h | An include file for the /usr/include/sys/termio.h header file | 
| /usr/include/termios.h | POSIX line-discipline structures and constants | 
| /usr/include/xcoff.h | Extended Common Object File Format structures | 
| /usr/include/sys/acct.h | Accounting structures | 
| /usr/include/sys/badisk.h | Bus-attached-disk structures | 
| /usr/include/sys/bbdir.h | Bad-block directory structure | 
| /usr/include/sys/bootrecord.h | Boot record structure | 
| /usr/include/sys/buf.h | Buffer header structures | 
| /usr/include/sys/cdrom.h | CD-ROM structures | 
| /usr/include/sys/cfgodm.h | Configuration object class structures | 
| /usr/include/sys/configrec.h | Disk configuration record structure | 
| /usr/include/sys/core.h | Core dump structure | 
| /usr/include/sys/debug.h | Traceback table or procedure-end table | 
| /usr/include/sys/device.h | Device switch table | 
| /usr/include/sys/deviceq.h | Device queue-management structures | 
| /usr/include/sys/devinfo.h | Device information structures | 
| /usr/include/sys/dir.h | Directory entry structures | 
| /usr/include/sys/display.h | Virtual display driver structures | 
| /usr/include/sys/dump.h | Component dump table structure | 
| /usr/include/sys/entuser.h | Ethernet device driver structures | 
| /usr/include/sys/errids.h | Error-log record identifiers | 
| /usr/include/sys/errno.h | Error codes | 
| /usr/include/sys/fd.h | Diskette device driver structures | 
| /usr/include/sys/file.h | File structure | 
| /usr/include/sys/fstypes.h | File-system parameter table | 
| /usr/include/sys/hd_psn.h | Layout of reserved space on the disk | 
| /usr/include/sys/ide.h | IDE device driver structures | 
| /usr/include/sys/inode.h | I-node structures | 
| /usr/include/sys/intr.h | Interrupt handler structures | 
| /usr/include/sys/ipc.h | Interprocess Communications (IPC) structures | 
| Item | Description | 
|---|---|
| /usr/include/sys/iplcb.h | Initial Program Load (IPL) control block structure | 
| /usr/include/sys/ldr.h | Loader structures and constants | 
| /usr/include/sys/low.h | Kernel Page 0 definition | 
| /usr/include/sys/machine.h | Machine dependent control registers | 
| /usr/include/sys/mbuf.h | Memory buffer structures | 
| /usr/include/sys/mdio.h | Machine device driver structures | 
| /usr/include/sys/mount.h | Mount structures | 
| /usr/include/sys/mpqp.h | Multiprotocol Quad Port (MPQP) device-driver structures | 
| /usr/include/sys/msg.h | Message queue structures | 
| /usr/include/sys/mstsave.h | Machine State Save Area structures | 
| /usr/include/sys/param.h | Process management constants | 
| /usr/include/sys/pri.h | Constants for process priorities | 
| /usr/include/sys/proc.h | Process table structure | 
| /usr/include/sys/pseg.h | Process private segment layout | 
| /usr/include/sys/reg.h | Machine-dependent registers | 
| /usr/include/sys/scdisk.h | SCSI-disk device driver structures | 
| /usr/include/sys/scsi.h | SCSI device driver structures | 
| /usr/include/sys/seg.h | Memory management constants | 
| /usr/include/sys/sem.h | Semaphore structures | 
| /usr/include/sys/shm.h | Shared-memory facility structures | 
| /usr/include/sys/signal.h | Signal structures and constants | 
| /usr/include/sys/socketvar.h | Sockets structures | 
| /usr/include/sys/stat.h | File status structure | 
| /usr/include/sys/systm.h | System global declarations | 
| /usr/include/sys/termio.h | Line discipline structures and constants for compatibility of Version 2 of the operating system | 
| /usr/include/sys/timer.h | Timer structures | 
| /usr/include/sys/tokuser.h | Token-ring device handler structures | 
| /usr/include/sys/trchkid.h | Trace hook IDs | 
| /usr/include/sys/user.h | User structure or user area (ublock) | 
| /usr/include/sys/utsname.h | UTSNAME structure (system name, node ID, machine ID) | 
| /usr/include/sys/var.h | Runtime system parameter structure | 
| /usr/include/sys/vfs.h | Virtual file system structures | 
| /usr/include/sys/vnode.h | Virtual i-node (v-node) structures | 
| /usr/include/sys/xcoff.h | Extended Common Object File Format structures | 
| /usr/include/sys/xmalloc.h | Heap structure | 
| /usr/include/sys/xmem.h | Cross memory service structures |