are simultaneous on the same level.
d. LT - Terminal on the specified line. LT can range from 1 to 16 with LINOP or LINWQ converting to the alpha addressing character A-P. Terminals on a line are required to be assigned starting with A and proceeding consecutively. Neither LL nor LT may reference a
. higher numbered line or terminal than has been assigned at system generation time or a LINOP error will result.
e. NDATA - This is the low core (FORTRAN high subscript) address of user's data table. Data table format is explained below.
15
o
o
I?O
o
Request entered in line queue successfully Line operation complete with no errors(CLDNM has been queued)
CALL paramenter in error, request not entered Repeated line operation failure, request can-celled (CLDNM has been queued)
(IND indicator of 5), as well as on a successful opera-tion (IND indicator at 3).
The type stop call is provided for rapid recognition of interrupts.
It will suspend typing in favor of more important operations on a line. CALL TYPSP will stop typing at completion of the current character and will allow the line queue to be scanned for other line requests. When no more entries remain in the line queue, typing will be continued at the point of its interruption. This call should be issued from any interrupt servicing subroutine that requires line access in less time than the maximum typing requirement. For example, a 600 baud line will require in excess of ten seconds to complete an 130 character message.
TYPEWRITER OUTPUT
The 1800/1896 Process Communication and Control System provides two methods. of typewriter output to the 1053:
1. Normal FORTRAN 'WRITE' operations with a 'FORMAT' statement.
2. Direct line operations CALLED by the user.
FORTRAN 'WRITE' STATEMENTS:
The TASK program of TSX has been modified to handle output to 1053 typewriters on the 1896 system from the normal FORTRAN I/O
sub-routines. Typewriters are assigned logical unit numbers for FORTRAN when the TSX system is built by the user, and the user initiates a message with the 'WRITE' and 'FORMAT' statements. In TSX, all
o
FORTRA~ typewriter messages or message units are buffered to disk, ();
occupying one sector per message unit. Control is returned to
17
J?Z-!II!!!tY".
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the user program immediately after buffering. Buffered 1053
messages are recalled by the RECAL subprogiam whenever their 1896 line is idle; therefore, typewriter messages have the lowest
priority of all line operations, (priority 225). The length of time between 'WRITE' statement and message typing is dependent upon the number of requests for that line which are in the line-queue. Messages are recalled from the buffer on a in, first-out basis; alert messages will be recalled before normal messages.
In TSX, alert messages are recognized by tne first character in the 'FORMAT' stai(~ment being a "Ribbon Shift Up". If a typewriter, or its line, is down, a backup typewriter specified by the user can be used. Error conditions such as disk buffer overflow are handled by a modified TYPEN program of TSX. A maximum of 16 typewriters, one of which must be an 1800/1053 typewriter, may
o
be supported by the 1800/1896 modified TSX system.o
Because both 'Printer Start' and 'Carriage Return-Line Feed' opera-tions are very time consuming, the user may tal-;e the option to permanently wire 'ON' his 1053 typewriters and to have the FORTRAN generated CRLF at the beginning of each typewriter message,
automatically deleted upon recall. With this option, message units may not be used, and it is the user's responsibility to place CRLF where needed. If the option is not taken at system generation time, a printer start character is automatically placed before the message unit or CRLF of the message when the message is recalled from disk buffer.
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/73
I
SEQUENCE OF OPERATIONS
The following sequence of operations is initiated by the user with
Set programmed interrupt for CAISS supervisor.
Recognition of programmed interrupt.
Search line-queue for highest priority request.
Build line~operation tables for terminal and multi-plexer addressing.
Trigger first interrupt from Conununications Adapter.
Level 0 interrupt for CAISS Device addressing.
Data transmit and receive.
Longitudinal redundancy check.
Clear line and set progralruned interrupt for CAISS supervisor.
Recognition of progranmwd interrupt.
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17Y
0',,:
Ib. Set line not busy, set user indicator.
c. Call diagnostic coreload if error has occurred.
6. User program recognizes operation complete code in user indicator.
!?~TA TABLES (Diagram 5)
The data tables required by the 1896 system are modeled after the normal 1800/1130 data tables. The address transmitted in the call sequence points to the low core end of the table, re-quiring in FORTRAM the high subscripted end. The first word in the data table is a word count specifying the number of words of data or the number of characters to be transmitted or re-ceived, depending on the conversion code. The high order bit is the chain indicator bit if this option is included. If the
o
chaining option is not included, this bits presence will be ignored.C·""·''
.,.'The system uses the low order 14 bits as a positive integer.
The second word specifies the conversion code in the high order - 4 bits, and for 1070 systems, the multiplexor address and mode
in the low order 12 bits. The conversion codes available are:
o -
Unpacked, one character per word.1 - Packed Digital, two characters per word.
2 - Unpacked Digital, one character per word.
3 - Analog Input (1070 only)--the converted binary value of one analog input point is stored in each word.
4 - 1053 output, the character to be printed is in the high order 8 bits, the number of filler
characters to follow is in the low order 8 bits.
5 - Packed, two characters per word.
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++WiliIliiUiiii ... iiiliMMiGialGII,iI1Gi1&QiQa;;:;;;g,£l1I,:gg;:, .... u·
i I
_-__ c_. ____ • _ _ _ • _ _ _ _ _ •.•••• _ _ _ . • • _ _ _ _
The difference in digital or normal conversion is the handling of the BCD zero, consisting of the 82 bits, which is converted to a binary
a
in Digital conversion, but left as'a binary A (1010) in normal mode; plus that Digital conversion concerns itself with only the four low order bits and ignores any higher order bits.The Chain Address word must be present and set correctly if chaining of data table is used. The contents of this word is used with no checking as the address of the next data table. Bad things could come of an incorrect setting here. Note that in MPX, a load
address function is provided to allow setting of this chain ad-dress that is remarkable simila~ to the one provided by the 1070 support package.
SKELETON COnE REQUIRE11ENTS
Approximate core requirements for the skeleton resident portions are given below. These core requirements are approximate and I will not be held responsible for them.
-TASK modifications for Typewriter support via FORTRAN I/O:
620 Words.
Subroutine LINOP/LINWQ plus the queue: 330 Words.
The type stop subroutine TYPSP: 30 Words.
CAISS Subroutine: 1200 Words plus 100 each for the chain
on Send and Type-Stop Options plus 40 Words per line attached.
The sum is about 2240 words for a reasonable system.
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0,
21 17('
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Process Contcact Momentcary
Contc3cts