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3.1 ABSTRACT: . . . . . . . . . . . . . . . . . . . . 3-1
3.2 PHYSICAL KNOBS -- A HISTORICAL OVERVIEW. . . . . . 3-1
3.3 PICTORIAL DESCRIPTION OF A KNOB: . . . . . . . . . 3-4
3.4 FIRST PASS KNOB GRAPHICS . . . . . . . . . . . . . 3-4
3.5 PRIMARY ATTRIBUTES OF A KNOB: . . . . . . . . . . 3-6
3.6 INFORMATION REQUIRED TO CREATE A KNOB: . . . . . . 3-8
3.6.1 KNOB_SETUP . . . . . . . . . . . . . . . . . . . 3-8
3.6.2 Knob Driver Communications . . . . . . . . . . . 3-9
3.6.3 Assigning A Knob . . . . . . . . . . . . . . . 3-10
3.6.3.1 Panel Assignments: . . . . . . . . . . . . . 3-10
3.6.3.2 Fortran Assignments: . . . . . . . . . . . . 3-11
3.6.4 Typical Driver . . . . . . . . . . . . . . . 3-11
3.7 KNOBS INTERNALS . . . . . . . . . . . . . . . . 3-14
3.7.1 KNOB_ASSIGN . . . . . . . . . . . . . . . . . 3-14
3.7.2 KNOB_DEASSIGN . . . . . . . . . . . . . . . . 3-15
3.7.3 KNOB_RESTORE . . . . . . . . . . . . . . . . . 3-15
3.7.4 KNOB_LEGEND . . . . . . . . . . . . . . . . . 3-16
3.7.5 KNOB_SETUP . . . . . . . . . . . . . . . . . . 3-17
3.7.6 KNOB_UPDATE_LOCAL . . . . . . . . . . . . . . 3-17
3.7.7 KNOB_UPDATE_GLOBAL . . . . . . . . . . . . . . 3-17
3.7.8 KNOB_DRIVER . . . . . . . . . . . . . . . . . 3-18
3.7.9 TPIO Ast Routine . . . . . . . . . . . . . . . 3-19
3.7.10 TPIO Routine . . . . . . . . . . . . . . . . . 3-19
3.7.11 Knob Communications . . . . . . . . . . . . . 3-20
3.8 DISPLAYS . . . . . . . . . . . . . . . . . . . . 3-22
3.8.1 Simple Graphics . . . . . . . . . . . . . . . 3-23
3.8.2 Foreground-Background Graphics . . . . . . . . 3-23
3.8.3 DEXEC Control . . . . . . . . . . . . . . . . 3-24
3.8.4 DISPLINE Routines . . . . . . . . . . . . . . 3-25
3.8.4.1 DISPLINE . . . . . . . . . . . . . . . . . . 3-26
3.8.4.2 DISPLINE_INIT . . . . . . . . . . . . . . . 3-27
3.8.4.3 DISPLINE_SKIP . . . . . . . . . . . . . . . 3-28
3.8.4.4 DISPLINE_PAGE . . . . . . . . . . . . . . . 3-28
3.8.4.5 DISPLINE_STAT . . . . . . . . . . . . . . . 3-28
3.8.5 Additional Display Utilities . . . . . . . . . 3-29
3.8.5.1 Database Single Unit Displays (DSPCATS) . . 3-29
3.8.5.2 HISTO . . . . . . . . . . . . . . . . . . . 3-29
3.8.5.3 STAT_COLOR . . . . . . . . . . . . . . . . . 3-30
3.8.5.4 ZPLOT Utilites . . . . . . . . . . . . . . . 3-30
3.9 COMMUNICATION FROM THE SCP TO A PANEL . . . . . 3-31
3.9.1 PNLWRIT . . . . . . . . . . . . . . . . . . . 3-31
3.9.2 PNLWRIT_SEND . . . . . . . . . . . . . . . . . 3-33
3.9.3 PNLWRIT_BLINK . . . . . . . . . . . . . . . . 3-33
3.10 CURSOR ADDRESSED LIMITED FACILITY (CALF) . . . . 3-34
3.10.1 Functional Description . . . . . . . . . . . . 3-34
3.10.2 Limitations . . . . . . . . . . . . . . . . . 3-38
3.10.3 Programming Notes . . . . . . . . . . . . . . 3-39
CHAPTER 3
KNOB SUPPORT
3.1 ABSTRACT:
The new system support for knobs for the SLC Control System
allows process variables (ie: Magnet Fields, Klystron
Phase) to be controlled from a wide variety of sources. The
new knob support ("type-2" knobs) is incorporated into new
and existing application knob drivers. Old knobs "type-1"
are no longer supported.
Design of system knob utility support and the implementation
in application driver routines is discussed.
3.2 PHYSICAL KNOBS -- A HISTORICAL OVERVIEW.
The two original environments which supported knobs were COWs and
CALFs (and PIGs). The COW has a 256 count/turn shaft encoder, while
the CALF has a set of Fast/Slow Up/Down buttons. Each application
knob driver (type-1) is responsible for all scaling, limits, and
labels. Each knob has a 16 character legend, with the last 6
characters reserved for the value (expressed in engineering units).
The current knob environment was driven by the needs of the
workstation console (WKS). Each knob has a set of ranges, a current
value, and a number of display options. The ranges consist of a local
"ruler" with higher resolution gradations and an "absolute" ruler with
the local range highlighted. An arrow/number points to the current
KNOB SUPPORT Page 3-2
value. There are several knob movement techniques under
consideration. The first proposal is supported as part of the initial
implementation (the "May-19th" proposal). All movements require the
same application support, and the difference is fully supported within
the system knob utilities.
Knob Movements:
i) The the display consist ONLY of labels, the current value and
three switches for selecting a "hardware" gain. Since there are
no rulers and no arrow, the only part of the display needing
updating is the current value. The value is changed by clicking
either of two mouse buttons (one for increasing the value, one
for decreasing it) in main part of the knob window.
ii) The arrow/number is "clicked" to a new position by the mouse and
cursor. There is a "redraw" region which repaints the local
ruler with the arrow centered.
iii) The arrow/number can be "clicked" to a new position, or
"clicked-dragged" back and forth. If the cursor leaves the
active window, dragging ceases. The redraw option (above) is
available.
iv) There is a "move up" and a "move down" area defined in the normal
windows as described above, which will move the arrow as
necessary. The local region will be rescaled as needed
automatically if movement is of this nature.
KNOB SUPPORT Page 3-3
v) The knob region is divided in logical areas, low gain on the
left, and high gain on the right. Two mouse buttons are used to
"click-move" the arrow up/down, and cursor movement is dependent
on the cursor's position in the window. The arrow will
automatically move, and the local region will be redrawn as
necessary.
KNOB SUPPORT Page 3-4
3.3 PICTORIAL DESCRIPTION OF A KNOB:
The following is an illustration of the original proposal of the
workstation knob. Most of the illustrated features are available with
the current version of SLC and DEC window management support.
TYPICAL WORKSTATION KNOB.
+----+----------------------------------------------+
|Menu| SCP_: |
+-+--+--------------------------------------------+-+
| | * 1.534 | |
| | V | |
|R| |---+---+---+---+---+---+---+---+---+---| |R|
| | 1.00 2.00 | |
| |-10.00 |------------------###----------| 10.00 | |
+-+-----------------------------------------------+-+
^
|
Rescale Region |
+-------------------+ (one of two)
| Knob Options |
+-------------------+
| Push Behind | <-- Pop-Up Menu
| Shrink to icon |
| Fast forward |
| Fast reverse |
| Increase gain |
| Decrease gain |------------~
| Restore knob |:
3.4 FIRST PASS KNOB GRAPHICS
The very first minimal knobs will have no rulers and no rescale
regions. The only way to change the value of the knob variable will
be with two mouse buttons defined to be "up" and "down" buttons. The
KNOB SUPPORT Page 3-5
graphics will look like this:
+----+------------------------------------+
|Menu| |
+----+-------------------------------+----+
| |fast|
| +----+
| |med |
| +----+
| |slow|
+------------------------------------+----+
The three square regions to the right will be used to modify the gain.
The middle region will be "normal" and the knob will come up with this
region highlighted. The upper region will reduce the gain; the lower
will increase it. The three possible gain settings (call them
"hardware settings" for now) will be multiplied by another (already
existing) gain factor which may be set from the application (e.g.,
from a touchpanel button). For the first pass, it will not be
possible for the operator to change the multiplicative factors
corresponding to these hardware gains; neither will they be modifiable
by the application from program control. A new gain region is
selected by clicking the left-most mouse button within the region.
This will cause an AST to store the new hardware gain for this knob in
an appropriate place and to highlight the region.
The large region in the picture above will have attached to it another
AST which will be sensitive to clicks of the right-most mouse button
(to increase the value of the knob variable by an amount proportional
to the product of the hardware gain and the application gain) and the
center mouse button (to decrease the value of the knob variable).
This AST will store sufficient information for the knob driver to know
by what amount the knob has been "rotated" -- it will not attempt any
KNOB SUPPORT Page 3-6
actual change in value or graphics itself -- and will set a flag
before returning. A click of the leftmost mouse button in this region
will merely pop the window to the front.
3.5 PRIMARY ATTRIBUTES OF A KNOB:
The following is a full list of the attributes of a workstation knob.
The calling sequence to establish knob-specific contexts (ie: total
range) are discussed under "KNOB_SETUP" below.
a) Knob ID -- The knob's ID, or number is currently asserted either
from the touch panel or hard coded in the knob_assign call (most
cases). The following suggestions are presented for thought:
o Ignore the explicitly supplied label, and dynamically
allocate from the free knob id pool.
o Use the dynamically allocated pool iff the knob id is not
specified.
b) Knob Position -- The position of the knob on the screen is
unresolved. The following suggestions are presented for thought:
o The position not be under the user's direct program control.
The user may, of course, "grab" the knob and put it wherever
he desires.
o The initial position be computed from the knob number. We
might establish a "clear area" of some corner for knob
placement.
o UIS willing, if there is a "conflict", the system be allowed
to find a suitable location.
c) Knob Label -- Any label is accepted as part of the knob
initialization. The string "KNOB " will be added to
the front of the supplied label.
d) Ordinate Label -- The descriptor of the units used in the
presentation of the scale.
e) Current "Value" -- Any value is accepted following a knob click
from the driver routine. The arrow is placed over the value
returned. If the value is beyond the range of the ruler, then no
arrow is drawn, and the rescale option must be requested prior to
any accepted "clicks". The value will be displayed. The initial
KNOB SUPPORT Page 3-7
value is part of the knob initialization.
f) Current Range -- The current range is the "length" of the ruler
displayed in the window. The initial value is part of the knob
initialization. Changing the "gain" from the menu will modify
the range.
g) Current Limits -- The limits will be chosen within the following
constraints:
o Arrow will be nearly centered on rescale or initialization.
o Limits will be bounded by the Absolute Limits.
h) Absolute Range and Limits -- The total range available to this
knob. The actual range of the device might be different, and
those limits will be explicitly checked by each knob driver. The
initial value is part of the knob initialization.
i) Rescale Region -- Any "click" in the rescale region at the edge
will re-scale the window, forcing a new computation of the
current limits.
j) Menu Options -- The following options might exist for the knob
menu. It is understood that the current implementation of UIS
does not allow direct manipulation of the menu options, so in
that sense, this is a wish list.
i: Fast Forward, Fast Reverse -- "Clicking" these entries will
be equivalent to "clicking" one current range to the
right/left. A rescale is forced, and the request th the knob
driver will be bounded by the absolute limits.
ii: Increase, Decrease Gain -- "clicking" this will change the
gain up/down in steps of 1, 3, 10. The current range and
limits are re-computed, and a rescale is forced.
iii: Restore Knob -- The knob is "clicked" with the initial
position, and a rescale is forced.
iv: Deassign Knob -- The knob is deassigned. Any movements of
process variables knobbed is not changed. The knob-id is
available for other knobs.
v: Exit this menu -- Go back to being a knob.
KNOB SUPPORT Page 3-8
3.6 INFORMATION REQUIRED TO CREATE A KNOB:
The workstation knobs (as shown above) consist of an arrow which is
"clicked" (or "dragged") from one value to another. The user now has
available information on the range or gains currently implemented.
The type of "knob" supported by the knob utilities (known as "TYPE 2"
control) where the knob creation is done with enough information to
allow workstation support. A knob becomes "type 2" as a function of
the initialization call. A type 2 knob will continue to be supported
for the CALF and COW hardware implementations.
The actions performed by the type 2 knobs are regulated by an element
KNOB.MODE found in the include '(KNOBS_DRIVER)', and are as follows:
o KNOB.MODE = KNOB_INIT -- The driver routine is responsible for
calling KNOB_SETUP (see below). This call may only be made once,
and at init time, and dynamically changes the knob support to the
"type 2" control.
The knob window (if wks) is drawn, and the legend is computed and
painted by the knob utility.
o KNOB.MODE = KNOB_ROT -- The knob driver uses a common block array
containing the current knob location and figures out the new
display coordinate from the knob coordinate. All units are in
engineering units.
The legend is computed and painted by the knob utility.
o KNOB.MODE = KNOB_END -- The knob driver may do something
associated with deassigning the knob.
3.6.1 KNOB_SETUP
The knob-routines are a bit more demanding of information for the WKS.
There will be an initialization routine telling more about the context
of each knob. This routine should be called by the driver routine
KNOB SUPPORT Page 3-9
during each assign (KNOB.MODE=KNOB_INIT). The calling structure is of
the form:
CALL KNOB_SETUP( the following parameters )
Where most of the following parameters are R*4 unless noted.
a) KNOB_LABEL (C*(*)) -- The label associated with the knob. The
knob utility will add knod-id type information to this. The
maximum length is unknown, but will be truncated as required.
b) ORDINATE_LABEL (C*(*)) -- The label associated with the current
range. No label (literally '') may be supplied, and the use of
mixed case (such as 'Volts', 'Nanoseconds', or 'Salary' ) is
preferred.
c) CURRENT_VALUE -- The starting value in engineering units.
d) CURRENT_RANGE -- See above. The "KNOB_GAIN" gain modifier in the
/KNOBS/ common block will be applied to the supplied range.
e) ABSOLUTE_LOWER -- The lower maximum value. This is ignored for
780 type knobs.
f) ABSOLUTE_UPPER -- The upper maximum value. This is ignored for
780 type knobs.
g) CLOSURE (C*(*)) -- Special hook for different data types.
Closure types of 'PHASE' indicate that +180.00 and -180.00 are
the same, and to take some user friendly action on crossing the
boundry, and type 'Z8.8' is a special formatting option used for
the test knobs on the COW.
3.6.2 Knob Driver Communications
The communication between the knob_utility and the drivers will be
through the use of a common structure. The include file is accessed
by the Fortran-77 command
INCLUDE '(KNOBS_DRIVER)'
A listing of the include file, with all the control variables follows:
C
C COMMON BLOCK FOR KNOB COMMUNICATION FOR "TYPE 2" KNOBS
C
C
KNOB SUPPORT Page 3-10
C note: this MAX is separately defined in KNOBCOMM.TXT
C note: these values are also in KNOBS.TXT (intentionally
C to avoid both includes in the same module)
C
INTEGER*4 KNOB_MAX, KNOB_INIT, KNOB_ROT, KNOB_END
PARAMETER (KNOB_MAX = 7, ! Maximum Knob number
> KNOB_INIT= 1, ! KNOB_ASSIGN CALL
> KNOB_ROT = 2, ! KNOB ROTATION CALL
> KNOB_END = 0) ! KNOB_DEASSIGN CALL
STRUCTURE /KNOB_STRUC/
Integer*4 ID ! The knob ID (0-n)
Integer*4 MODE ! KNOB_INIT, etc.
Real*4 CURRENT_VALUE ! The "mouse" location
Real*4 DISPLAY_VALUE ! The desired "arrow" location
Logical*4 RESCALE_FLAG ! Force user to rescale
Real*4 LAST_VALUE ! Used to by driver detect conflicts
Real*4 CURRENT_RANGE ! The current range
END STRUCTURE
RECORD /KNOB_STRUC/ KNOB
COMMON /KNOB_DRIVER/ KNOB
The knob driver routines will be called with no arguments:
CALL
The application knob driver should gain access to the common block
through the indicated include file.
3.6.3 Assigning A Knob
Knobs may be assigned either of two ways. The most common method is
through panel code (see ASSIGN: in the index). The panel method
usually removes the necessity of writing a special routine to call the
KNOB_ASSIGN subroutine. Knobs may also be created from inline fortran
calls.
3.6.3.1 Panel Assignments: - The driver must be known to the system
through a LIST_CALL call. this is done in the sharable image's
KNOB SUPPORT Page 3-11
xxxINIT.FOR or in the users DEVINIT.FOR. The following lines must
exist:
EXTERNAL TEST_KNOB (or whatever the driver is called)
CALL LIST_CALL(TEST_KNOB, 'TESTKNOB')
The panel code will assign your knob driver to the indicated knob as
requested by the user.
3.6.3.2 Fortran Assignments: - The application routine may request a
knob assignment directly through the following protocol:
EXTERNAL TEST_KNOB
ISS = KNOB_ASSIGN(, TEST_KNOB)
The call will directly assign TEST_KNOB as the driver for the knob
.
3.6.4 Typical Driver
The following is a "typical" knob driver, "type-2". There is no
attempt made to represent reality in examples of database use, message
service, CAMAC, etc.
**********************************************************************
**********************************************************************
SUBROUTINE TEST_KNOB
!
! **MEMBER**=SLCLIBS:somelib
!
! a "typical" knob driver. This is to serve as an example, and parts
! of the routine have been left deliberatly vague.
!
! rkj -- 4/86
!
IMPLICIT NONE
KNOB SUPPORT Page 3-12
! common block from facility containing primary, micro, unit, etc.
INCLUDE '(MY_COMMON)/NOLIST'
INCLUDE '(ACNTRL)/NOLIST'
INCLUDE '(KNOBS_DRIVER)/NOLIST'
! storage as required to remember attributes of the created knob
INTEGER*4 PRIMS(0:KNOB_MAX), MICROS(0:KNOB_MAX),
> UNITS(0:KNOB_MAX), ERRORS(0:KNOB_MAX)
! other variables as necessary
REAL*4 ABS_LOWER, ABS_UPPER, RANGE, etc.
CHARACTER*16 LABEL
!---------------------------------------------------------------------
c Global initializations, etc. See note 1.
IF (ACNTRL(1) .NE. 0) THEN
RETURN
ENDIF
c Assign the knob
IF (KNOB.MODE .EQ. KNOB_INIT) THEN
PRIMS(KNOB.ID) = PRIMARY
MICROS(KNOB.ID) = MICRO
UNITS(KNOB.ID) = UNIT
ERRORS(KNOB.ID) = 0
c -- compute the label
WRITE(LABEL, '(A4,1X,A4,I5)') PRIMARY, MICRO, UNIT
c -- do necessary DBGETS to establish the following:
c -- , , ,
ISS =
c -- perhaps fail. See note 2.
IF (.NOT. ISS) THEN
CALL KNOB_DEASSIGN(KNOB.ID)
GOTO 101
ELSE
CALL KNOB_SETUP(LABEL, 'Furlongs', CURRENT_VALUE, RANGE,
> ABS_LOWER, ABS_UPPER, 'normal')
ENDIF
c Rotate the knob
ELSEIF (KNOB.MODE .EQ. KNOB_ROT) THEN
c -- get value out of database,
c -- test for a knob conflict. See note 3.
IF (VALUE .NE. KNOB.LAST_VALUE) THEN
CALL ERR_SEND(xxx_KNOBCONFLICT, PRIMS(KNOB.ID),
> MICROS(KNOB.ID), UNITS(KNOB.ID), VALUE)
c -- in case of conflict, update current value
KNOB.CURRENT_VALUE = VALUE
c -- most drivers have display values equal current values
KNOB.DISPLAY_VALUE = KNOB.CURRENT_VALUE
c -- and return
KNOB SUPPORT Page 3-13
GOTO 100
ENDIF
c -- send a update, do some CAMAC, or whatever is appropiate
ISS =
c -- count errors. See note 2.
IF (.NOT. ISS) ERRORS(KNOB.ID) = ERRORS(KNOB.ID) + 1
IF (ERRORS(KNOB.ID) .GT. ) THEN
CALL ERR_SEND(, ...)
CALL KNOB_DEASSIGN(KNOB.ID)
GOTO 101
ENDIF
c Clear the knob
ELSEIF (KNOB.MODE .EQ. KNOB_END) THEN
101 CONTINUE
c -- free whatever resources have been used.
c -- most drivers do nothing special here.
ENDIF
100 RETURN
END
**********************************************************************
**********************************************************************
Note 1: For initialization control of routines defined with the
LIST_CALL system, see under ACNTRL in the index.
Note 2: The call to KNOB_DEASSIGN does not result in this subroutine
being called again. Therefore, any exit handling appropiate should
now be handled.
Note 3: The correct response to a conflict is to update the current
and display values, and return. For workstation knobs, the user
requested a specific value, and failed (this pass). For cow knobs,
there will be a stream of knob requests for as long as the knob is
turned, and a missed movement is certainly no worse than the quantum
jump associated with the knob conflict.
KNOB SUPPORT Page 3-14
3.7 KNOBS INTERNALS
At the heart of the knob utility support is the single proceedure
KNOB_DRIVER. KNOB_DRIVER is organized as a state-driven processor, or
state machine. Associated with the definition of each knob is the
structure element KNOBS().NEXT_MODE, or the next state in the
processor. (The typical state is KNOB_NULL, or "do nothing"). The
routine KNOB_DRIVER loops through all supported knobs, processing each
knob as indicated in the state descriptor KNOBS().NEXT_MODE until the
"KNOB_NULL" state is acheived. KNOB_DRIVER is not reentrant , and
returns immediately if so called. (As happens during a Knob Deassign
called from the application knob driver). All of the higher level
utilities execute the following three actions:
a) Argument checking. i.e., is the knob number legal?
b) Set next state in structure for the knob.
c) Call KNOB_DRIVER.
The internals of the knob support are not visiable to the applications
level knob routine.
3.7.1 KNOB_ASSIGN
This routine associates a supplied driver with a knob. The driver is
initially called for initialization, routinely during knob movements,
and once for the deassign (if the deassign is not initiated by the
driver).
KNOB SUPPORT Page 3-15
The states are as follows:
o Check arguments
o See if knob is currently assigned.
o Set knob state to KNOB_END
o Call KNOB_DRIVER
o Load new driver address
o Set knob state to KNOB_INIT
o Call KNOB_DRIVER
3.7.2 KNOB_DEASSIGN
This routine dis-associates a driver with a knob. The driver is
called for any exit handling, if the call to KNOB_DEASSIGN did not
originate from the driver.
The states are as follows:
o Check arguments
o Loop through supplied or ALL* knobs
o Set knob state to KNOB_END
o Call KNOB_DRIVER
o Loop through supplied or ALL* knobs
o Test all states for KNOB_END
o Set state to KNOB_SHORT_END
3.7.3 KNOB_RESTORE
This routine restores the position ar a knob to the start value.
KNOB SUPPORT Page 3-16
The states are as follows:
o Check arguments
o Prompt as necessary for knob number
o Restore original value to knob
o Set knob state to KNOB_ROT
o Call KNOB_DRIVER
3.7.4 KNOB_LEGEND
This routine is the routine which has the most workstation dependent
behavour. The routine draws the window as necessary, scale factors,
current value, etc. For COW's and CALF's, there is just the
computation of the 16 character legend from the supplied string and
display value.
The states are as follows:
*** COW's and CALF's
o Check arguments
o Compute string
o Send string to knob-device
*** Workstations
o No arguments
o Do some or all of the following as indicated by the KNOB.MODE
and the contents of KNOBS().xxx
o Create Window
o Fill window
o Draw/Move arrow and number
o Delete window
KNOB SUPPORT Page 3-17
3.7.5 KNOB_SETUP
This routine initializes the knob-specific structures to describe the
knob completely to the support routines.
The states are as follows:
o Check that the calling context is correct
o Set knob type to "type-2"
o Copy the contextal information to the appropiate common blocks
o Apply universal gain-modifier factor to supplied RANGE
3.7.6 KNOB_UPDATE_LOCAL
This routine updates the local KNOB structure from the universal knob
structures as needed.
The states are as follows:
o Copy 5 words of data into "KNOB." structure
o If knob is "type-1", update /KNOBS/ common block for older
routines.
o Save a copy of the current value
3.7.7 KNOB_UPDATE_GLOBAL
This routine updates the global KNOBS structure from the local knob
structure as needed.
KNOB SUPPORT Page 3-18
The states are as follows:
o If "type-1", convert /KNOB/KNOB_POS() into Current Value
o Copy 3 words of data from "KNOB." structure
o If the new current value is different from the previous (see
KNOB_UPDATE_LOCAL), update position. (as happens following a
knob conflict.
3.7.8 KNOB_DRIVER
See introduction to this section for an overview of KNOB_DRIVER. The
knob_driver routine supports (or will) the following states of knob
activity:
a) KNOB_NULL -- The do-nothing state
b) KNOB_INIT -- Initialize the knob, call application driver
c) KNOB_ROT -- Rotation or new value has occurred. Call
application driver.
d) KNOB_END -- Deassign the knob, call application driver,
delete window or clear legend.
e) KNOB_SHORT_END -- Delete the window or clear legend. A
knob_deassign has been signaled by the application knob
driver.
f) KNOB_RESCALE -- Recompute the local scale's location, redraw
window.
g) KNOB_NEWGAIN -- Recompute the local scale's size, redraw
window.
The loops and general driver states are as follows:
o Clear "Finished" flag
o Return if reentrantly called
o Loop until "Finished"
o Set "Finished flag
o Loop over all knobs
KNOB SUPPORT Page 3-19
o Loop until this knob's next state is KNOB_NULL
o Service next_mode state, including some of the
following:
o call KNOB_UPDATE_LOCAL
o call
o call KNOB_UPDATE_GLOBAL
o call KNOB_LEGEND
3.7.9 TPIO Ast Routine
This routine is the interrupt handler for the knob-utility. There is
almost no computing done at this level, and many activities such as
formatted writes are specifically prohibited at this level.
The states for this routine are console type dependent, and are as
follows:
o Integrate "delta" type knob movement into a common block
o Save cursor position in the window's local coordinate system
o Set a flag describing class of operation in a common block
o Set the "some knob activity" flag in a common block
o Set the Local Event Flag to signal the scheduling of the TPIO
group
3.7.10 TPIO Routine
This routine is scheduled as a result of some panel, menu, or knob
activity.
KNOB SUPPORT Page 3-20
The states are as follows:
o If "some panel activity" flag is set, do something.
o If "some knob activity" flag is set, then
o Loop over all knobs
o Evaluate the type of operation requested (if any)
o Update the global structure
o Set the knob's next_mode state flag
o Call knob_driver
o If "some menu activity", ...
o etc.
3.7.11 Knob Communications
There are a number of include files and common blocks used for
internal knob communications.
The knobs_driver include is described above.
The internal communications is acheived through the include:
INCLUDE '(KNOBS_DRIVER)'
INCLUDE '(KNOBS)'
A listing of the include file, with all the control variables follows:
C
C COMMON BLOCK FOR KNOB COMMUNICATIONS FOR KNOB UTILITY
C
C
c -- include some "knobs_utility" states
c (most states are in KNOBS_DRIVER.TXT)
INTEGER*4 KNOB_SHORT_END, KNOB_NULL
PARAMETER (KNOB_SHORT_END = 4,
> KNOB_NULL = -1 )
INCLUDE '(KNOBS_DRIVER)'
1 C
KNOB SUPPORT Page 3-21
1 C COMMON BLOCK FOR KNOB COMMUNICATION FOR "TYPE 2" KNOBS
1 C
1 C
1 C note: this MAX is separately defined in KNOBCOMM.TXT
1 C note: these values are also in KNOBS.TXT (intentionally
1 C to avoid both includes in the same module)
1 C
1 INTEGER*4 KNOB_MAX, KNOB_INIT, KNOB_ROT, KNOB_END
1 PARAMETER (KNOB_MAX = 7, ! Maximum Knob number
1 > KNOB_INIT= 1, ! KNOB_ASSIGN CALL
1 > KNOB_ROT = 2, ! KNOB ROTATION CALL
1 > KNOB_END = 0) ! KNOB_DEASSIGN CALL
1
1 STRUCTURE /KNOB_STRUC/
1 Integer*4 ID ! The knob ID (0-n)
1 Integer*4 MODE ! KNOB_INIT, etc.
1 ! the order of these is used in '(KNOBS_UTILITY)'
1 ! - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
1 Real*4 CURRENT_VALUE ! The "mouse" location
1 Real*4 DISPLAY_VALUE ! The desired "arrow" location
1 Logical*4 RESCALE_FLAG ! Force user to rescale
1 Real*4 LAST_VALUE ! Used to by driver detect conflicts
1 Real*4 CURRENT_RANGE ! The current range
1 END STRUCTURE
1
1 RECORD /KNOB_STRUC/ KNOB
1 COMMON /KNOB_DRIVER/ KNOB
1
1
STRUCTURE /KNOBS_STRUCTURE/
! the order of these is used in '(KNOBS_DRIVER)' and in KNOB_UPDATE
! - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
Real*4 CURRENT_VALUE ! The "mouse" location
Real*4 DISPLAY_VALUE ! The desired "arrow" location
Logical*4 RESCALE_FLAG ! Force user to rescale
Real*4 LAST_VALUE ! Used to by driver detect conflicts
Real*4 CURRENT_RANGE ! The current range
! end of "public" elements
! - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
INTEGER*4 NEXT_MODE ! Next MODE flag
INTEGER*4 TYPE ! 1 or 2
REAL*4 POSITION ! Current Position (type 1)
REAL*4 START_VALUE ! Used for a knob restore
REAL*4 ABSOLUTE_LOWER ! Absolute limits
REAL*4 ABSOLUTE_UPPER ! '' ''
REAL*4 CURRENT_LOWER ! Current limits
REAL*4 CURRENT_UPPER ! '' ''
INTEGER*4 DRIVER_ADDRESS ! %LOC() of the knob driver
CHARACTER*12 CLOSURE ! Closure type
CHARACTER*40 KNOB_LABEL ! Knob label, incl. SCP_ID, etc.
CHARACTER*12 ORDINATE_LABEL ! Ordinate value
END STRUCTURE
RECORD /KNOBS_STRUCTURE/ KNOBS(0:KNOB_MAX)
COMMON /KNOBS_UTILITY/ KNOBS
VOLATILE /KNOBS_UTILITY/
KNOB SUPPORT Page 3-22
C
C This common is a copy of '(KNOBS)', and used for the support of
C type 1 knobs.
INTEGER*4 KNOB_MODE ! The calling mode for the knob driver
INTEGER*4 KNOB_ID ! The ID of the knob
INTEGER*4 KNOB_POS(0:KNOB_MAX) ! Knob position
REAL*4 KNOB_GAIN ! First time only gain modifier
COMMON /KNOBS/
> KNOB_MODE,
> KNOB_ID,
> KNOB_POS,
> KNOB_GAIN
3.8 DISPLAYS
Graphic CRT displays, textual lineprinter output, and graphical line
printer output are controlled by the Display Executive, DEXEC. DEXEC
handles all of the SCP-COW/CALF communication protocol so that the
operation of a display subroutine devolves into combinations of
calling HANDIPAK display facilities, the DISPLINE facility, and
Unified Graphics routines that ADD data to a display buffer.
Display routines should include the common block /ACNTRL/. The value
of ACNTRL(1) is used to steer the operation of a display. A value of:
o -1 indicates initialization. Any first time definition of
logical names necessary for panel operation should be made at
this point. Note that any extensive operations needed for
the display but not needed for the first invocation of the
display should be saved for a later call. This allows
significantly faster startup of the SCP, particularly
relevant since the vast majority of displays will not be used
with any single SCP startup.
KNOB SUPPORT Page 3-23
o 0 indicates a request for a graphics display. Note that
HANDIPAK and DISPLINE internally interpret ACNTRL(1) and can
be called for ACNTRL(1)=0, 1, or 2.
o 1 indicates a request to clear a display. This might be a
null request depending on context.
o 2 indicates a request for a textual lineprinter display or a
display that can be formatted for a CALF. The display writer
normally satisfies this request with HANDIPAK or DISPLINE,
although output produced on Fortran logical unit 6 will
normally be displayed.
3.8.1 Simple Graphics
A normal display that is doing custom graphics by using the Unified
Graphics routines should specify the buffer SCPBUF which is found in
the Fortran library member (SCPBUF). All clearing and output control
of the buffer is handled by DEXEC.
3.8.2 Foreground-Background Graphics
Certain displays may wish to update at relatively high rates to allow
real time observation of machine performance; an obvious example is
the Beam Position Monitor display. Such displays are optimized by
dividing them into background and foreground segments. The background
segment is generated once and transmitted once to the COW;
subsequently only the foreground segment is generated and transmitted
to the COW. The COW performs the erasure of the older foreground
KNOB SUPPORT Page 3-24
segment and the inclusion of the new segment. Thus extremely
elaborate backgrounds may be designed for high repetition rate
displays without performance penalties.
The first step in a foreground-background display is to identify the
routine as such to the SCP by adding the parameter DX_BCKG to the
GRP_BITS in the LIST_DISP call (See the section on Logical Names).
This and the other specialized parameters are defined in (SCPBUF).
The display routine when producing graphics (ACNTRL(1)=0) should steer
on ACNTRL(2). If this variable is equal to DX_FORE then a foreground
display should be generated, and if it is equal to DX_BCKG then the
background display should be generated. This origin of the graphics
buffer may be always used, but it is not necessary for simple
displays.
3.8.3 DEXEC Control
All DEXEC options are controlled by the logical name variable DXMODE,
which is normally set from a touch panel. The presently supported
options are:
1. VERSATEC
requests the present graphics display be "copied" from the
CRT to the Versatec plotter.
2. PRINT
KNOB SUPPORT Page 3-25
requests lineprinter output and will call displays with
ACNTRL(1)=2.
3. ALTDISP
requests that the display be routed to an alternate CRT on a
COW. Although the standard COW has only one graphics screen,
the system can handle additional CRT's.
4. OVERLAY
requests that the "existing" display not be erased and the
new display be overlayed. A maximum of two display routines
may be overlaid. Do not confuse this option with overlays of
graphics from a single display routine; ie one routine can
make an arbitrary number of calls to the HANDIPAK displays.
5. CLEAR
requests that the DEXEC display tables be cleared, thus
clearing the CRT to blank. Normally, a display is on the
screen until replaced by another. Do not confuse this option
with that implied by ACNTRL(1)=1.
3.8.4 DISPLINE Routines
Displays consisting entirely of Ascii text are generated using the set
of standard DISPLINE routines. These routines format text strings to
the COW color monitor, the CALF display area, or the line printer.
The position of the string is specified by line and column number and
automatic line incrementing and paging is handled internal to the
KNOB SUPPORT Page 3-26
DISPLINE routines.
3.8.4.1 DISPLINE -
SUBROUTINE DISPLINE(STRING,COLOR,IX,IY)
o STRING is the Character string to be output.
o COLOR is the Character string specifying a standard Unified
Graphics color which will be interpreted as the COW color or
CALF graphic rendition to be used. The correspondence
between color and graphic rendition is:
White - Normal
Green - Bold
Yellow - Underscore
Blue - Bold-Underscore
Magenta - Blink-Underscore
Cyan - Reverse Video
Red - Blink Reverse Video
o IX is an Optional I*4 starting column number (default=DL_X)
(n.b. COW scope has 73 characters across)
o IY is an Optional I*4 change in row number relative to the
last call (default=1); e.g. IY=0 will print on same line as
the last call.
DISPLINE is the general display routine for outputting character data
to the COW scope, CALF terminal, or line printer. It contains
provision for automatic line incrementing and paging. After each
KNOB SUPPORT Page 3-27
call, the row number DL_Y is incremented by 1. If the result is
greater than DL_LINES, the flag DL_NEW_PAGE is set TRUE, the page
DL_PAGE is incremented by 1, and DL_Y is reset to 1.
For output to COW or CALF, output occurs only if DL_PAGE=DL_DISP_PAGE.
DL_DISP_PAGE may be set in call to DISPLINE_INIT (default=1). This
feature is useful in instances where it is difficult to calculate
paging structure in advance. In this case one makes calls to DISPLINE
for all pages, and only the correct page is actually output.
3.8.4.2 DISPLINE_INIT -
ENTRY DISPLINE_INIT(JDPAGE,JX,JY,JPAGE,JLINES,DY)
o JDPAGE is the Optional I*4 Page to be output (default 1) If
supplied, it MUST be a variable so displine can do paging
internally and return calculated page number to caller
o JX is the Optional I*4 Starting column number for all output
not overridden by argument IY in call to DISPLINE.
(Default=1)
o JY is the Optional I*4 Line number for next output
(Default=1)
o JPAGE is the Optional I*4 Page number for next output
(Default=1)
o JLINES is the Optional I*4 user-supplied Total number of
lines per page (Default = 30 for CALF, 40 for COW)
KNOB SUPPORT Page 3-28
o DY is the Optional R*4 user-supplied COW scope line height
(row size/screen size) (Default = .025)
DISPLINE_INIT initializes a display for subsequent calls to DISPLINE.
It must be called once for each display before any text is output.
All arguments are optional and over-ride default values put into
common block /DSPLNBLK/.
3.8.4.3 DISPLINE_SKIP -
ENTRY DISPLINE_SKIP(NSKIP)
DISPLINE_SKIP skips NSKIP lines. NSKIP is Optional I*4 and defaults
to 1.
3.8.4.4 DISPLINE_PAGE -
ENTRY DISPLINE_PAGE
DISPLINE_PAGE advances pointers to the next page.
3.8.4.5 DISPLINE_STAT -
SUBROUTINE DISPLINE_STAT(STRING,STAT,IX,IY)
o STRING is the Character string to be output.
o STAT is the I*2 status word to control the color of the
display. The low order 4 bits are interpreted as a status
summary mask and the output color is chosen by a call to
KNOB SUPPORT Page 3-29
STAT_COLOR.
o IX is an Optional I*4 starting column number as in DISPLINE.
o IY is an Optional I*4 change in row number as in DISPLINE.
DISPLINE_STAT uses DISPLINE to output a line of text with the color
chosen according to the low order status bits in STAT.
3.8.5 Additional Display Utilities
3.8.5.1 Database Single Unit Displays (DSPCATS) -
SUBROUTINE DSPCATS(MICRO,PRIMARY,UNIT)
o MICRO is the I*4 ASCII string containing the Micro name
o PRIMARY is the I*4 ASCII string containing the Primary name
o UNIT is the I*4 Integer or ASCII string containing the unit
number
DSPCATS is a standard routine to display all known database
information about a given unit specified by Micro, Primary, Unit. An
error message is printed if any argument is equal to 'ALL*'. Paging
is done internally using the universal panel variable Panl_page.
3.8.5.2 HISTO -
KNOB SUPPORT Page 3-30
SUBROUTINE HISTO
HISTO is a driver subroutine which may be called from a Panel to
output HANDYPAK histos which have been defined and filled by other
user software. If executing on a COW, the histogram goes to the
monitor with a call to the normal Handypak HOUT routine. If executing
on a CALF, it calls AA_HOUT to put the histogram on the display area
of the terminal. The histogram name is selected on the panel and
passed to the routine in the variable HISTNAME. It is expected to be
only 4 ASCII characters long. If undefined, an error message is
printed.
3.8.5.3 STAT_COLOR -
CHARACTER*7 FUNCTION STAT_COLOR(STAT)
STAT_COLOR is a function to calculate the standard SLC color
corresponding to the I*2 status supplied in STAT. Only the lowest 4
bits are used as a mask to determine the color coding as follows:
STAT = 4 - Cyan (Offline)
= 8 - Red (Sick)
= 2 - Yellow (Ok but not good)
= 1 - Green (Good)
= 0 - White (No status)
3.8.5.4 ZPLOT Utilites -
KNOB SUPPORT Page 3-31
The ZPLOT routines are a set of utility routines designed to
facilitate the plotting of database entries as a function of their Z
position along the Linac. The routines may also be used to plot
simple X,Y co-ord data supplied by the user. A full description of
the routines and their calling sequences may be found in the VAXSOFT
help library under the subtopic DISPLAYS.
3.9 COMMUNICATION FROM THE SCP TO A PANEL
A SCP program may add data to a panel by use of the routine PNLWRIT.
This routine adds a user string to a symbolically defined location on
the panel. Warning: When initializing a new panel, PNLWRIT can only
write to button locations that have been defined on the current or
previous lines of the panel definition file.
3.9.1 PNLWRIT
PNLWRIT(BTN_NAME_STRING,STRING,LINE,FLAGS)
where:
BTN_NAME_STRING is a character variable of length le 8 containing the
symbolic button location defined by any of the panel commands BUTTON,
SWITCH, SELECT, SHADOW, etc.. It is passed by descriptor so Integer
or Real variables containing Ascii strings must be passed as
%Descr(Var_name). The string '*' selects the current button location
as the destination of the output.
KNOB SUPPORT Page 3-32
STRING is character variable containing the ASCII text to be
displayed. The length of string is limited only by the scissoring of
graphic material that would lie outside the boundaries of the screen
image. PNLWRIT does not respect button boundaries (except for line 2
of a CALF where STRING will be truncated to 6 characters), nor does it
honor carriage return-line feed sequences. Normal button strings
should contain le 6 characters.
LINE is an OPTIONAL I*4 variable describing the vertical position of
the STRING with respect to the button outline. A button has space for
4 lines; numbered from 1 through 4 and beginning at the top of the
outline. If LINE is omitted, it will default to 4.
FLAGS is an OPTIONAL Integer*2 variable which allows the user to
specify special modes of operation for PNLWRIT. To date two options
are available. Depending on the value of FLAGS, PNLWRIT
1. will or won't warn the user if the button specified in
BTN_NAME_STRING is not found (default is warn). Normally the
default of warn should be used. Nowarn is useful when the
routine calling PNLWRIT may justifiably be invoked with the
"wrong" panel up. Note: In the special case where the
output string is blank or the special COW blank bar
character, no warning is issued regardless of FLAGS.
2. will or won't accumulate a series of PNLWRIT messages in a
buffer so they can be sent to the graphics device in a single
transfer (default is not to accumulate; i.e., each message is
sent immediately). Note: when initializing a new panel,
everything on the panel is buffered regardless of the FLAGS
KNOB SUPPORT Page 3-33
argument.
Users wishing to specify a value for FLAGS other than the default
should INCLUDE '(PANEL)', wherein appropriate parameters are defined.
For example, if the user wished the output to be buffered, but wants
to be warned of a non-existent button, the call would be
CALL PNLWRIT(btn-name-string,string,line,PNLWRIT_BUFF)
3.9.2 PNLWRIT_SEND
For convenience, an additional routine PNLWRIT_SEND can be used to
send a buffer of previously constructed messages to the graphics
device. The calling sequence is
CALL PNLWRIT_SEND
There are no arguments required.
3.9.3 PNLWRIT_BLINK
An additional routine PNLWRIT_BLINK is used by the terminal input
routines DLOG_* to output a blinking bar to the last line of the
current button. The calling sequence is
CALL PNLWRIT_BLINK
KNOB SUPPORT Page 3-34
There are no arguments required.
3.10 CURSOR ADDRESSED LIMITED FACILITY (CALF)
Because the supply of COWs is limited, and to provide for debugging
and remote usage, it is desireable have a single terminal system
capable of emulating most of the functions of a COW. The CALF
provides this capability, and utilizes the cursor addressing features
of the Ann Arbor Ambassador terminal. The system standardizes on the
Ann Arbor because of its extensive cursor addressing capabilities and
its 60 line screen. If the terminal is equipped with an Ann Arbor
Graphics Master unit, the the CALF is converted to Panel Interactive
Graphics (PIG).
3.10.1 Functional Description
The screen is divided into 4 separate regions: Lines 1/30 are used as
the display area, Lines 31/56 are used as the touch panel area, line
57 is used for dialog between user and computer, and lines 58/60 serve
as a message area from the VAX.
To use the CALF, run the SLC Control Program (SCP) as normal (e.g.
command SCP). In response to the prompt for COW ID, type TERMINAL (or
any abbreviation thereof) for a CALF or GRAPHICS (or any abbreviation
thereof) for a PIG. You can also switch between CALF and PIG mode
using PF keys 6 and 7 (see below).
KNOB SUPPORT Page 3-35
To use the CALF touch panel, use the up/down/left/right arrow keys to
position the cursor inside the desired button. Pushing ENTER is then
the equivalent of pushing a touch panel button. Pushing the HOME key
will move the cursor to the nominal INDEX panel position (top right).
To use the CALF knobs, first select the desired knob (0-3) by pushing
PF(9-12). Note: to prevent accidental knob changing, the knobs are
deactivated if no knob activity occurs within 60 seconds, in which
case you must reselect the knob. The selected knob will be shown in
reverse video on the screen. Assign knobs as usual using the touch
panel. The KP7 (T-CLR) key will increase the knob at slow speed, KP1
(SSA) will decrease at slow speed, KP9 (T-SET) will increase at fast
speed, and KP3 (ESA) will decrease at fast speed.
Because the CALF uses the terminal in cursor addressed mode, the PF
keys are used to allow one to switch modes:
RESET: Resets Ann Arbor Graphics Master Unit and terminal to
power-up conditions (destroys SCP capability). Works only
for terminals equipped with Graphics Masters.
RESET: Complete Ann Arbor terminal reset, except for
programmable keys (use SETUP-Z to get default key settings)
and Graphics Master (use RESET for this if you are willing
to destroy SCP capability).
PRINT: Print the entire screen on terminal printer.
PRINT: Print just the display region of the screen.
EDIT: Return to Cursor to touchpanel (use after PRINT or
PRINT.)
KNOB SUPPORT Page 3-36
INSERT: Print displayed graphics plots on terminal printer
ERASE: Clears graphics screen and returns to alphanumeric mode.
PF1: Places the top 30 lines of the screen in normal mode
while making inaccessable the bottom 30 lines of the
screen. This is useful in DEBUG mode, allowing one
to converse with the debugger without destroying the
touch panel region of the screen.
PF2: Places the top 30 lines of the screen in normal mode
and erases this section while making inaccessable the
bottom 30 lines of the screen. This is useful in DEBUG
mode, allowing one to converse with the debugger without
destroying the touch panel region of the screen.
PF3: Places the screen in cursor addressed mode, restoring
any previously saved touch panel. Useful in leaving
DEBUG mode and returning to normal program.
PF4: Allow SCP global messages to be broadcast to the terminal.
(See PF5 below).
PF5: Disallow SCP global broadcast messages. Because the message
area of the screen is limited, it is sometimes convenient to
suppress global messages and limit messages to those unique
to the SCP being run.
PF6: Enter PIG mode (CALF with graphics)
PF7: Enter CALF mode from PIG mode.
KNOB SUPPORT Page 3-37
PF8: Button Macro Abort/Attention.
PF9: Activate Knob 0
PF10: Activate Knob 1
PF11: Activate Knob 2
PF12: Activate Knob 3
PF1s: Toggle terminal key click mode.
PF2s: Toggle terminal block cursor mode.
PF8s: Spawn CATER.
KP8(^) : Move cursor up
KP2(v) : Move cursor down
KP4(<-): Move cursor left
KP6(->): Move cursor right
ENTER: Activate touch panel button
KP7(T-CLR): Knob up slowly
KP1(SSA) : Knob down slowly
KP9(T-SET): Knob up quickly
KP3(ESA) : Knob down quickly
Note: By popular demand, the block cursor mode is used to
make the cursor easier to find on the touch panel. If
this bothers you then use the toggle block cursor mode
KNOB SUPPORT Page 3-38
key (PF2s) to change it.
3.10.2 Limitations
1. Because Ann Arbors without Graphics Masters do not have true
graphics capability, displays for CALFS (as opposed to PIGS)
are limited to purely alphanumerics (see programming notes
below).
2. Because the screen is cursor addressed, one cannot read and
write to the CALF as though it were a normal terminal. Hence
one must abide by software conventions and use packaged
CALF-compatible software. See programming notes below.
3. WARNING!!!! Writing to the terminal in CALF mode (i.e.
using escape sequence cursor controls) when a PIG is in
graphics mode has catastrophic consequences. As of this
writing, global messages are broadcast to the terminal in
CALF mode at random times and hence are beyond the control of
the SCP program. Hence, until this problem is fixed, DISABLE
GLOBAL MESSAGES WHENEVER YOU ARE IN PIG MODE!!!!!
4. Because the CALF Touch panel is squeezed into a small number
of lines, there are several limitations on the format of
Script messages and Button labels.
o The Script options to select LARGE size letters are
ignored. Script output to either line 3 or line 4 will
be written to line 3.
KNOB SUPPORT Page 3-39
o The Button labels are written in 2 lines of 9 characters
each, not 3 lines of 6 characters each as on a COW touch
panel. This means that labels formatted to look
beautiful on a COW may look rather incomprehensible on a
CALF.
o The alternate line argument in a call to PNLWRIT causes
the output string to be truncated to 6 characters and
formatted similarly to the button labels.
3.10.3 Programming Notes
1. In writing error messages and other output to the terminal,
one should not write directly to the terminal (since it would
then appear at some arbitrary location on the screen), but
rather use the routine COWRITE or where logging is desired,
the SLC error service.
2. Similarly, one should not read data directly from the
terminal but rather should use one of the DLOG_* routines.
In addition to being CALF-compatible, these routines are
generally more convenient to use than standard FORTRAN WRITE
and READ statements.
3. For alphanumeric displays, one should not use the unified
graphics routines directly, but rather use the COW/CALF
compatible routines of the DISPLINE utility. DISPLINE
outputs data using integer column and row numbers, and has
some facilities which recognize the difference in screen
sizes to make paging easier. (The COW scope is 73 characters
x 40 lines; the CALF display area is 80 characters x 30
lines.) DISPLINE also performs automatic line incrementing
KNOB SUPPORT Page 3-40
and is thus somewhat more convenient to use than COUT.
Nonetheless one should always bear in mind that the CALF
screen size is only 30 lines long.
4. For histograms, the subroutine HISTO provides a COW/CALF
independent interface to HOUT.
5. For true graphic displays, one should avoid spending cpu time
to prepare non-displayable displays by verifying that the SCP
is actually running on a COW or a PIG rather than a CALF.
This can be done by calling LOGICAL FUNCTION GRAPHICS() which
returns TRUE if the SCP has graphics capability.
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Jeffrey Miller
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