FILE IDENTIFICATION

-M:CO 22 9 3 3 3 17 17 4 8 86

-M:SO 22 9 ^I 3 3 3 17 17 4 8 86

M:PO 22 9 3 3 3 4 8 52

M:LO 22 9 3 3 3 4 8 52

M:LL 22 9 3 3 3 4 8 52

M:DO 22 9 3 3 3 4 8 52

M:GO 22 9 3 3 3 8 48

M:EO 22 9 3 3 3 17 17 17 4 4 9 8 116

M:SL 22 4 3 3 3 8 43

M:AL 22 4 3 3 3 8 43

Field Use This means that proceSsors must explicitly open DCBs for

which device assignments will be tested.

TYPE

DEY

Bits 18-23 of word 1 of a DCB. These bits specify a code for the type of device con-nected to the DCB (printer, terminal, card reader, etc.).

Bits 24-31 of word 1 of a DCB. These bits specify an indexto the monitordevicetable.

Under CP-Y, all device assignments are direct. This means that DEY always contains a direct device assign-ment. A complete layout and description of DCBs is co~tained in the CP-Y /BP Reference Manual, 90 17 64.

The same effect can be obtained by the CORRES device CAL, but the CAL is much slower than the direct compar-ison. The direct comparison of the combined TYPE-DEY fields is meaningful only if the DCB has been opened.

FILE IDENTIFICATION

All on-I ine processors use a common format and common character set for constructing file identifiers (fid). The standard format is

[

.account ]

name • account. password

•• password

where name, account, and password consist of character strings with maximum lengths of 11, 8, and 8, respectively (name has a maximum of 131 characters for CCI, Edit, and PCl and a maximum of 10 characters for Link and load).

Any of the following characters may be used:

A-z a-z 0-9 LJ $ * % ^#

@

Shared Processor Programming 91

Lowercase alphabetical characters are not available on all fi Ie identification (fid) or a terminal identifica-tion (ME).

ON indicates that ROM output is to be on a new file.

OVER indicates that ROM output is to be over an existing fj Ie.

rom specifies that the relocatable object module produced by the processor is to be directed to a specified file (fid). If no file is specified, out-put is directed to a special file that may be sub-sequently referenced by a dollar sign.

list specifies that a file (fid), a line printer (LP), or the terminal (ME) should be used for listing.

If list is not specified, no listing output is produced.

These specifications are implicit ASSIGN and SET commands for the DCBs M:SI, M:GO, and M:LO. A processor call causes the specified processor to be executed with M :SI DCB input from the file sp. Processor output through M:GO DCB

However, the processor may examine these and other parts of the command I ine that is in its J IT buffer (J :CCBUF).

Processors may reside in storage in three forms:

1. System swap storage contains absolute shared copies of frequently-used processors. These copies can be located and loaded quickly. The absolute shared

92 Shared Processor Programming

processor file is created during system initialization and contains reentrant processors that are shared among all concurrent users.

2. The :SYS account may also contain copies of processors in load module form. Processors in this form cannot be loaded as quickly as absolute processors, but the :SYS account may be useful during processor construction, debugging, and extension. Public programs in the specifying the requested processor. The monitor routine STEP checks to see if this user has any processor restrictions. processor. The options and their corresponding bit assign-ments are as follows: corresponding bits are set. Each processor must assign mean-ing to the bits and interpret them. Unassigned bits are available for future use. Checks of these bits should be made on each write command since TEL allows on-line users to interrupt the processor and turn on or off the LO, GO, and DO devices.

Each processor should establish conventions to maintain orderly output when two or more DCBs are connected to the same devi ceo The usual convention is that if diagnostic

output has been written via M:LO, and M:LO and M:DO abnor-mal condition (see theCP-V/BPReference Manual, 90 1704 for a description of abnormal conditions). To obtain program to examine parameters.

TERMINAL 110

An on-line user may direct output to his Teletype at any time during execution of a processor. Simi larly, portions of the input to a processor may come from a Teletype. In general, Teletype I/o is the same as other I/O in its use of M:READ and M:WRITE operators and the standard abnor-mal and error situations. However, Teletype I/O has some features that are significantly different from those for other devices. Some of the differences require special attention by processors, but the interface is designed in such a way that processors wi II not have to know whether or not I/O operations are via Teletype, providing they observe certain conventions. On terminal I/O, like all I/o, the user should note that byte displacements in the DCB remain in effect until replaced, once they have been given. The . special problems associated with Teletype I/O are outlined

in the following paragraphs.

END CHARACTERS

On input from a Teletype, each record read is terminated by an end character (CR, FF, LF, RS, US, FS, GS). The end character, if any, is included in the actual record size (ARS) count reported in the DC B (bi ts 0- 14 or word 4).

Each processor must interpret the different end characters.

Processors do not have to know that input is via Teletype, type, are translated to the standard EBCDIC character set.

The hexadecimal codes for EBCDIC characters are listed suppfied by each write under the following circumstances:

1. The DCB is not M:UC.

2. The suppress space option is not specified.

Thus, under ordinary circumstances, carriage return char-acters will be supplied when output consists of one line per write and the DCB is connected to a terminal. By using the suppress space option or by writing through M:UC, the pro-gram may supply carriage returns exactly to requirements-ei ther none or severa I for each write CAL.

Shared Processor Programming 93

In designing a response to messages that contain parity error characters, two facts are important:

1. The user has already been informed of the error by the

In the absence of special considerations unique to the pro-cessor, it is recommended that lines received with lost data be sent back to the terminal together with the comment

"EH?". This procedure is helpful as an aid in diagnosing faulty terminals and communication lines.

END-OF-FILE

If unknown operations are requested of the COC routines (e.g., write end-of-file), the abnormal code for beginning-of-tape wi II be returned. If there is no abnormal address,

It is sometimes necessary to print a line with special spacing or without a carriage return. Processors can obtain result in single spacing.

94 Shared Processor Programming

Parameter VFC

Meaning

If this flag is set, the COC routines simulate the printer's vertical format control as speci-fied in the first character of the text lines skipping six lines and printing the heading information fol-lowed by the print line. and account number, user identification and I ine number, page number, and possibly an administrative message.

Headings specified in the DCB of the read or write are pro-duced after the automatic heading with position, text, and page number as specified in the C P-V /BP Reference Manual,

Simulated tab stops can be set by a processor with the TAB neces-sary to record current carrier position (which for backspace depends on terminal type). Terminals that have a physical backspace may, at the user's option, use a "backspace-edit" mode for intra-line editing. (Reference: CP-V/TS Reference Manual, 90 09 07.) loca-tion following the interrupted instrucloca-tion by execuloca-tion of the M:TRTN procedure. A program can return break added to the previous contents of the fi I e, thereby extend-ing it. File extension simulates output to physical devices, al-though normally assigned to devices. They include: M:LO, LL, DO, PO, BO, SL, SO, CO, AL, EO, and GO. support installation-specific command processors. Infor-mation about the programming of command processors is outlined below.

Generally, command processors have the same restrictions as I isted for shared processors previousl y. In addition:

Command Processor Programming 95