HP 3000 Manuals HP 3000 Manuals
Operation
MKNOD determines how to create the files based on the arguments passed to
the program. When creating a device link or streams (character-type)
file, you must enter both the major and minor numbers. To create a
device link file, enter a major number of 0 and the LDEV number of the
device as the minor number. To create a streams file, enter a major
number greater than 0.
Syntax
mknod "name c|p major minor [link_name]"
Parameters
name Creates a special or fifo file including the
program name in the pathname.
c|p Creates a device link file or streams file if this
argument is 'c' (character type).
Creates a fifo file or pipe if this argument is
'p'.
major Major number. The following major numbers are
valid:
0 Creates a device link. The
minor number represents the
LDEV number.
1-254 Creates a streams file.
minor Minor device type. This is used in conjunction
with the major number option to provide a UNIX
compatible device specification. The interpretion
of the minor number is dependent on the value of
the major number. If the major number is 0, then
this number represents a LDEV number. If the major
number is > 0, then this number represents a
streams connection to a driver.
link_name Creates the streams file with a link_name. This
name is an eight-character MPE link_name (from the
NMMGR link screen).
When the special file is created, it can be accessed through the HPFOPEN
intrinsic and the C library "open" interface. The 0_NONBLOCK option can
be specified using open.
MKNOD sets a CI variable mknodvar with the value 0 if successful. If
errors occur, it returns the file system error status.
To create a fifo file called MYFIFO:
mknod "myfifo p"
To create a device link file for LDEV 7:
mknod "/dev/tape7 c,0,7"
To create a streams file with a link_name of DTSLINK, a major number of
1, and a minor number of 10:
mknod "strmfile c,1,10,dtslink"
You can use the LISTFILE command to display special files. For example:
LISTFILE /dev/@,2
PATH= /dev/./
CODE -------------LOGICAL RECORD----------------SPACE----- FILENAME
SIZE TYPE EOF LIMIT R/B SECTORS #X MX
128W FBf 0 1 1 0 0 * MYFIFO
128W FBs 0 1 1 0 0 * STRMFILE
128W FBd 0 1 1 0 0 * tape7
:LISTFILE /dev/tape7,5
**********************
FILE: /dev/tape7
FILE CODE : 0 FOPTIONS: BINARY,FIXED,NOCCTL,DEVICE LINK
BLK FACTOR: 1 OWNER : **
REC SIZE: 256 (BYTES) GROUP ID: **
BLK SIZE: 256 (BYTES) SECURITY--READ :
EXT SIZE: 0 (SECT) WRITE :
NUM REC: 0 APPEND :
NUM SEC: 0 LOCK :
NUM EXT: 0 EXECUTE:
MAX REC: 1 **SECURITY IS ON
FLAGS : NO ACCESSORS
NUM LABELS: 0 CREATED : THU, AUG 24, 1993 3:12 PM
MAX LABELS: 0 MODIFIED: THU, AUG 24, 1993 3:12 PM
DISC DEV #: 1 ACCESESED:THU, AUG 24, 1993 3:12 PM
SEC OFFSET: 0 LABEL ADDR: **
VOLNAME : MPEXL_SYSTEM_VOUME_SET:MEMBER1
DEV TYPE : DEVICE LINK
LDEV : 7 IO CLASS: TAPE
Additional Discussion
For more information on streams and device link files, refer to the
HPDEVCREATE intrinsic in the MPE/iX Intrinsics Reference Manual
(32650-90028).