The multi-access system on the 1906A is called MOP (Multiple On-line Programming). It allows a number of users to input and edit files, initiate jobs and, in some circumstances, run jobs interactively. This all takes place while batch jobs are being run in the background. There are many types of terminal available on the MOP system. Each has a typewriter-like keyboard (with additional keys used for control purposes) and some method for displaying messages from GEORGE. The simpler devices have printing (like a typewriter) while the more complex display the textual output on a cathode ray tube. In general, any terminal may be used as long as:
Many terminals have paper tape readers and punches attached which, in some circumstances, may be used for input and output. However, this is not recommended as care is needed to ensure that control characters are present in the correct places on input, Also, the 1906A will add a number of control characters on output which may not be expected.
Terminals may be connected to the 1906A locally by internal wiring at ACL. Alternatively, terminals which are remote from ACL can be connected using Post Office telephone lines.
To generate some of the special control characters, it is often necessary to press a special key marked CTRL, together with one or more keys simultaneously. In this section, a set of keys to be pressed at the same time will be written separated by dashes. For example:
CTRL-A
This indicates that the key A is pressed while the key marked CTRL is held down.
The purpose of the four main control characters is:
PEASE TYPE CORRECTLYAs the second letter (L) has been missed, it is easier to CANCEL the whole of this line rather than BACKSPACE all the way back to this point. The CANCEL character is usually produced by CTRL-X.
Most terminals will have a number of switches and buttons to control the power and connection to the 1906A. Before the terminal can be used, it must be connected to the appropriate power supply. Local connection to the 1906A is achieved by a 25-way plug which must be inserted in one of the appropriate sockets to be found in most offices and rooms at ACL. The main terminals in use at ACL are:
Most offices and rooms at ACL have 25-way sockets which are wired to a central switchboard. Terminals in offices will normally be plugged into the socket permanently. Once the terminal has been switched on and started, sending a BREAKIN character should cause the 1906A to reply. If no reply occurs, the possible reasons are:
Remote terminals are connected to the 1906A via Post Office telephone lines which may be leased or may be part of the switched public network. Terminals on leased lines operate in the same way as local ones except that the connection is permanent. It is unlikely that the terminal will ever be disconnected from the 1906A.
To obtain a connection to the 1906A via the public switched network, the user requires a DATEL 200 modem supplied by the Post Office (or possibly an acoustic coupler of some form). To make the connection, the user must:
If the user is unable to make a connection, he can get additional information by:
At the end of a MOP session, the telephone handset should be replaced. To disconnect the call on some modems, it is necessary to press the button on the handset marked NORMAL.
Both local and remote terminals should be switched off when not in use. This reduces the chance of fire, conserves power and lengthens the life of the terminal. For local terminals, the switchboard can see that the terminal has been switched off and the operator can then allocate the line to another user.
It is important that the terminal is not switched off until the 1906A has completed its output. This is signified by the message:
CLOSED DOWN AT ....
The message ends with the current time.
Once a connection has been made to the 1906A, it can be woken up by sending a BREAKIN character. The possible responses are:
THIS IS GEORGE 4 MK . ... . ON .....This indicates that a proper connection has been made and the MOP session can start.
Once the terminal has received the GEORGE sign-on message, the user is able to communicate with the system. The sign-on message is followed by the symbol' ← which is the standard invitation for the user to type. If nothing is typed for a few seconds, the computer will time-out and send the message:
CLOSED DOWN AT ....
The 1906A can be woken up again by sending another BREAKIN character (for remote users, the close down will disconnect the modem). During the MOP session, a failure to type in response to the symbol ← will cause another time-out. The message following the time-out will depend on whether the user is logged-in. If not, the message is as above. Once the user has logged-in, the message following a time-out will be:
TIMED OUT AT ....
In this case, the response to a BREAKIN character will be:
RESTARTED AT ....
If the time-out occurs in the middle of a line of input, this will be lost and, on restarting, the line will have to be input again. If the terminal is left in the time-out state for a few minutes, the user will be automatically logged-out. If this appears in the middle of an edit, either the oldfile will be kept (CORRECT) or the newfile with the remainder of the oldfile (EDIT).
The invitation to type is often preceded by the current time. This allows the user to keep a detailed record of the progress of the MOP session.
Once the user has received the invitation to type, he may type lines which can be up to 2000 characters in length. Usually a line will be quite short - less than 80 characters. It is terminated by an ACCEPT character. However, if the number of characters to be input is longer than can be typed on a single line, it can be continued on the next if a dash (-) immediately precedes the ACCEPT symbol.
For example:
THIS- IS A- VERY- LONG LINE
This line could also have been typed as:
THIS IS A VERY LONG LINE
Normally the only characters that will be accepted are those in the standard ICL 64-character GRAPHIC set. Two facilities are provided for correcting typing errors:
CANCEL←
ABC←DEFG←HThis line is equivalent to:
ABDEH
Normally each line of input will eventually be followed by another request to type, A breakdown of the system can result in one of the following responses in place of the request to type:
THE SYSTEM HAS TEMPORARILY CLOSED DOWNThis indicates that the 1906A has failed in some way. When the system restarts, the terminal will revert to NOUSER context and the user must log-in again. All files that are open for writing or appending, when the system breaks, are lost.
TRANSMISSION ERROR PLEASE RETYPEThis indicates that the last line input was incorrect when it arrived at the 1906A. If the terminal is a local one, this will most likely be due to a failure in the terminal. For remote terminals, it is more likely to be a genuine transmission error - especially in the prime shift. It could also be due to a modem failure. The user should retype the line. If transmission errors occur frequently, the remote user could try to remake the connection in the hope of a better line. If this does not solve the problem, the user should notify the 1906A operators (023-583-388). It is probably worth trying another port into the 1906A to see if this makes any difference. Failing this, it probably indicates a terminal fault which should be reported to the 1906A operator.
In the middle of a MOP session, It is also possible to get the messages WAIT and LINE CLOSED. These have already been described in E.2.3. In the case of WAIT, it is usually worth waiting a few minutes to see if the problem resolves itself. The user should refrain from hitting the BREAKIN key as this may affect the operation being performed.
A MOP session starts with the user logging in. This is in response to the sign-on message:
THIS IS GEORGE 4 MK....ON.....
An example of the LOGIN command to be typed is:
LOGIN MOPSMITH,:NTBE34
The two parameters that have to be provided are the jobname and username. The jobname consists of up to 12 alphanumeric characters starting with a letter. This is a name by which the job is known to the system. At ACL, it is requested that the jobname for a MOP session should include the name of the user and the letters MOP. This allows the 1906A operators to know who is operating the MOP terminal. As the output contains MOP in the title, the operator will also know that it is not associated with a job that has been input by the batch peripherals. The jobname must be unique in the user's proper directory. If the user lists his directory, an entry will appear with this name. It will have a generation number of 1 and language code B1B0. An entry of this form appears for each of the user's jobs that are in the system including those in the Secure Jobwell (Part I) and represents the monitoring file (C.9.1) for the job. The second parameter is the username which has been supplied to the user. At ACL this consists of a colon followed by four alphabetic characters and two digits. The first two letters define the user's project while the second two define his location.
The possible replies to the LOGIN command are:
This usually indicates that the username does not exist in the system. For a new user, this may mean that the username has not yet been added to the system. For an established user, it will normally indicate a typing error or a transmission error.
This implies that the terminal has been left in BREAK-IN context. Typing QUIT will return the system to the normal state when LOGIN will be possible.
This implies that the terminal is already logged in. It would normally indicate that the terminal is already in use. It would not occur if the GEORGE sign-on message had just been typed but could occur in response to the standard invitation to type.
This indicates that the LOGIN command has been accepted but that the maximum number of MOP jobs allowed has been reached. If the terminal is left, the system will eventually continue the LOGIN sequence when another MOP job can be allowed. If the user does not wish to wait, sending a BREAK-IN will cancel the attempt to log-in. The user should not just leave the terminal as, in this case, when the LOGIN sequence continues, it will be left halted waiting for a reply. In this state, a MOP position has been allocated to this terminal and will not be available to another user.
The correct password should be typed, in which case the system will respond with a message of the form:
STARTED :NTBE34,MOPSMITH,12SEP74 14.04.38 TYPE:MOP
Full details concerning passwords are given in E.3.2. In some instances, the sign-on message is followed by:
WAITING FOR FILE TO BE FREE
This just indicates that the system cannot access a file that it needs. Almost immediately the request to type will follow and the user may proceed. There is no need to take any notice of this message. If the previous job was abandoned by the system, logging-in with the same jobname can cause a long wait while the previous monitoring file is being printed. Users are recommended to give a different jobname for each session.
When the username is added to the system initially, no password is allocated to it. In this case, it is only necessary to press the ACCEPT key to complete the LOGIN sequence. There is never any necessity for the user to define a password for his username. However if he does not, it will always be possible for another user either inadvertently or maliciously to access his files and perhaps destroy them. Users are strongly recommended to define a password for their username as soon as possible.
A password can be defined initially or a new password can be defined to replace an existing one by the NEWPASSWORD command (D.2.6). An example is:
NEWPASSWORD ITSME
The characters ITSME would be the new password. The password may be up to 12 characters from the standard ICL 64~character set. It is recommended that only alphanumeric passwords are defined. Spaces within the password are significant. Spaces at the end will be ignored.
It is a time-consuming and expensive task to find out a user's password if he forgets it. Users should take special care to remember their passwords.
During the LOGIN sequence, the user should type in his current password in response to the message TYPE PASSWORD. The possible error messages are:
An incorrect password has been given. The LOGIN command should be entered again and the correct password given next time.
This indicates that the jobname in the LOGIN command was invalid for some reason. In the example, the jobname had been given as 27 while it should have started with an alphabetic character.
This indicates that the user already has a file in his directory with the same name as the jobname.
If the user types his password at the terminal, it will be listed on the printer. Therefore, the user should make sure he removes his output from the terminal before leaving it. Alternatively, if the terminal has a SIMPLEX/DUPLEX switch, by placing the switch in the DUPLEX position while the password is typed, no listing will appear. The user should put the switch back to the SIMPLEX position before pressing the ACCEPT key.
A complete LOGIN sequence might be:
THIS IS GEORGE 4 MK 7. 7G ON 12SEP74 WAITING FOR FILE TO BE FREE 15.15.10← LOGIN MOPSMITH,:BADUSERNAME ERROR IN LOGIN : USERNAME/PASSWORD INVALID 15.15.20← LOGIN MYFILE,:NTBE34 TYPE PASSWORD← GOODWORD ERROR IN PARAMETER 1 IN LOGIN : JOBNAME MYFILE NOT UNIQUE 15.15.30←LOGIN MOPSMITH,:NTBE34 TYPE PASSWORD← BADWORD ERROR IN LOGIN : USER NAME/PASSWORD INVALID 15.15.40← LOGIN MOPSMITH, :NTBE34 TYPE PASSWORD← GOODWORD STARTED :NTBE34,MOPSMITH, 12SEP74 15.15.50 TYPE:MOP 15,15.60←
Once the LOGIN sequence is complete, the user is in USER context and the MOP session can start. There is a NEWS facility which causes information to be printed automatically after a LOGIN. This should be read carefully as it may well be relevant to what the user intends to do.
A MOP session ends when the user types the command LOGOUT. This command cannot be used in BREAK-IN context. Therefore, if, in response to the LOGOUT command, the following message appears:
14.06.19←LOGOUT ERROR IN LOGOUT : THIS COMMAND IS NOT ALLOWED IN BREAK-IN CONTEXT 14.06.29←
The user should type the QUIT command and then input the LOGOUT command again.
At this stage, the user can ask for some or all of the categories of the monitoring file to be output on the lineprinter. The possible categories are given in the description of actiononmf (D.1.2). The standard setting is for no information to be output on the lineprinter. The user will get some monitoring information output at the terminal.
This will indicate the amount of time used and the number of documents listed.
To list the whole of the monitoring file on the lineprinter requires:
LOGOUT ALL
With the standard TRACE setting (D.8.2), very little information gets put in the monitoring file for a MOP session.
It is also possible to retain the monitoring file in a named file by using the RETAIN parameter. For example:
LOGOUT RETAIN(MYMONFIL)
This allows the user to examine the monitoring file at a later date. This could be useful if the user has forgotten where he has reached in a piece of work. However, the standard TRACE setting for MOP is that only LOGGING information gets sent to the monitoring file. For this to be of any use, the user would first have to change the TRACE setting (D.8.2).
If a user does not reply to the request to type for a few minutes, the system will automatically generate a LOGOUT (see E.2.3). It will be preceded by the message:
ABANDONED BY OPERATOR INTERVENTION
It is possible for certain faults in the connection between the terminal and the 1906A to cause the automatic LOGOUT. In either case, any files being used will be closed and no information should be lost.
All entries sent to the monitoring file are also sent to the MOP terminal except that commands are not listed. If they were, each command would be printed twice at the terminal. The user may well find that, once he gets experienced, he does not need to see certain messages. This is particularly true of messages in the COMMENT category. The REPORT command (D.8.1) may be used to restrict those categories sent to the terminal. For example:
REPORT ALLBUT,COMMANDS,COMMENT
This will not print comments or commands at the terminal. Users should be careful not to remove too many classes as in some circumstances they may then get confused about what has happened.
The REPORT command can be called any number of times. Information can be suppressed during just one part of a session. The command REPORT NONE, for example, immediately before LOGOUT will stop the budgeting information being printed.
Another command, which' is useful in conjunction with the REPORT command, is the TRACE command (D.8.2). This allows the user to modify the information that is being sent to the monitoring file and, therefore, what is being printed at the terminal.
The error messages output by GEORGE are often verbose and, in many cases, the error is quite obvious if the user is at all experienced. ACL have added a command which, once it has been called, replaces the standard messages by the message:
EH?
The command to replace the error messages is XQUIET (D.8.9). The messages can be established again by the command CANCEL XQUIET.
In some circumstances, the user may not be able to understand the error with just the reduced form. Therefore, there is another command, XPRINTLAST (D.8.10), which prints the error message in full. For example:
10.10.10← XQUIET 10.10.20← RUBBISH EH? 10.10.30← XPRINTLAST ERROR IN RUBBISH : THIS IS NOT A COMMAND 10.10.40←
The main functions performed in a MOP session are:
There is usually very little difference in the way the MOP user calls GEORGE commands from the way they are used in the background job or batch input. The following points, however, are peculiar to the HOP user.
The input of files is described in C.3.3. The main point that the MOP user must remember is that if the file being input is still open when the machine breaks then it will be lost. To save large amounts of retyping, it is sensible to split a large file into a number of smaller files as this will lower the risk of losing a file. For example:
INPUT A1,T**** ....... **** INPUT A2 ....... **** COPY A2,A1(APPEND) ERASE A2
This will produce the single file A1 terminating with ****. An alternative method is to input the first part of the file and then to extend this using the CORRECT command.
A long pause during the input may well result in a time-out. The user should remember, on restarting (press CTRL and A simultaneously), that the partially complete line will be lost and must be retyped (E.2.3).
A full description of file editing is given in Part G and MOP users should read this Part carefully.
The two main methods of running jobs are using TASK and the RUNJOB command. One great advantage of using the TASK system (Part B) is that, if the MOP session continues after the job has been submitted, it will send displays back to the terminal showing the progress of the job through the steps of compilation, consolidation and execution. The user knows exactly when a job is completed and can immediately look at the results assuming they have been returned to a file. Many of the packages produced at ACL have their own special macros for running jobs. In a number of cases, these call TASK to initiate the job and so the same display facilities are available. It is strongly recommended that the TASK system is used wherever possible.
Jobs submitted to the 1906A will be scheduled according to the jdparameter on the JOB or RUNJOB command (D.1.2). The main scheduling parameters are the jobtime, store size and number of magnetic tape decks required. When using TASK, these scheduling parameters are derived from the TASK parameters. For example, the JT parameter will indicate the jobtime to be used for scheduling purposes. The user is strongly advised not to request more facilities than he requires as this will adversely affect the time he waits before the job is run. If the estimated jobtime is too large by a factor of 2, the job will wait approximately twice as long.
The displays from TASK will be returned to the jobname that issued the job. If the user logs out, the displays will not be sent. However, if the user logs in at a later time with the same jobname, then any displays issued during the new MOP session will be sent to the terminal.
It is usual to call TASK directly. However, if a standard set of commands need to be obeyed before a call of TASK, there is nothing to stop the user defining a macro and calling this. However, issuing a RUNJOB on a file containing a TASK call will mean that the RUNJOB initiates a background job. The call of TASK will then be from a background job and, consequently, no displays will be sent to the terminal.
If the user is unable to LOGIN due to the limit on the number of users being reached, it is still possible to issue jobs using the RUNJOB command. In NOUSER context, the form of the command is slightly different as it must include the username. For example, the user might have wished to run the job:
TASK FORTRAN,*CR FRED,JT 2 MINS
Before logging in, this could be initiated by:
RUNJOB MOPSMITH,:NTBE34,TASK,PARAM(*CR FRED),JD(JT 2 MINS)
The system will ask for the user to give his password before the job will be accepted.
The main information required by the user is the state of his jobs. Each job that enters the system will either be in the Secure Jobwell or be executing. If it is neither of these categories then it is either finished or has been lost. The main command that the user will call is:
STATE MOPSMITH1,:NTBE 34
This will give the user details about the job specified. Full details are given in D.5.10. It should be remembered that this information only gets updated about every five minutes. To check that a job is actually running and how far it has progressed, the user should call the WHATSTATE command (D.5.3).
Another method, which can also be used to check whether a job is in the system, is to list the user's main directory by LISTDIR (D.3.11). An entry with the name of the job and language code B1B0 will appear if the job is still in the system.
From time to time, the user may overrun the amount of file space or the number of files he is allowed (I.2.2.3). To get a complete map of his own filestore, the user should call the LSTR macro (T.1.1). Files that are no longer required should be ERASEd. If the file needs to be kept but is not in use at the moment, the user may either LISTFILE it to the card punch or papertape punch or. he may use the COPYOUT facility (T.3.1) to transfer it to magnetic tape. Once the transfer is complete, the file may be erased. It can be read back in at a later date if required.
Care should be taken when erasing pseudo directories. If the directory name itself is ERASEd then all files in that directory will also be erased. The user is protected against doing this inadvertently by the directory having the ERASE trap set off. The trap for the file must be reset by the TRAPGO command (D.3.15) before it can be erased.
It is possible for a user to enter a job in the system and then realise that there is some error in it. In this case, it is desirable to remove the job rather than letting it run and waste machine time. The action required depends on whether the job has been started or not. The user should, therefore, first use the STATE command (D.5.10) or the WHATSTATE command (D.5.3) to ascertain its state.
If the job is still in the Secure Jobwell, it can be abandoned by calling REMOVE (D.5.11). For example:
REMOVE MOPSMITH2,:NTBE34
This will cause the job specified to be started by the system with zero jobtime which will cause it to delete immediately.
If the job has already started, it can be abandoned by first connect to it and then deleting it. Suppose the MOP user has the jobname MOPSMITH. A background job can be issued by:
TASK FORTRAN,*CR FRED
This will be entered in the Secure Jobwell with jobname FOR-MOPSMITH and will eventually be run. If, while it is running, the user wishes to abandon it, he should type:
CONNECT FOR-MOPSMITH
The current MOP job, MOPSMITH, will be logged out and the relevant budgeting information printed. This will be followed by some information indicating the state of the job. The MOP user is now connected to the job FOR-MOPSMITH which is suspended at the point reached so far. The user should type:
QUIT
This will cause the macro being obeyed to terminate. The message END OF MACRO will be printed followed by the monitoring information concerned with the core image. The MOP user at the terminal has a residual core image and should immediately finish the job by calling:
LOGOUT
This will terminate the job FOR-MOPSMITH and the relevant budgeting information will be printed. No monitoring file will be printed on the lineprinter for the background job FOR-MOPSMITH unless it is specified in the LOGOUT command. It is unlikely to be of any interest unless it is necessary to know how far the job has reached in its execution.
The JOBQ facility is a means of leaving a job in a safe place in the computer for later running by the 1906A operators. It is used for jobs whose scheduling requirements exceed any limits for direct submission currently in force, or for jobs which demand special action or attention by the operators.
The information about the job must be appended to a file :OPERATORS.JOBQ. The first part should be a RUNJOB command in a form for input from a batch peripheral. It should be followed by any relevant comments (F.3.1). For example:
INPUT QFILE,T**** RUNJOB SMITH,:NTBE34,TASK,PARAM(*CR FRED,JT 2 MINS),JD(JT 2 MINS) RUNJOB SMITH2,:NTBE34,MYFILE,JD(JT 5 MINS) PLEASE ENSURE FIRST JOB HAS COMPLETED BEFORE SECOND IS RUN COPY QFILE,: OPERATORS.JOBQ (APPEND)
The 1906A filestore resides on discs and magnetic tapes. The files being used at the moment are kept on-line. If a file is not used for a number of days, it is likely that the file will be removed from the disc and placed on magnetic tape (it is then off-line). If a user attempts to access a file that is off-line, a RETRIEVE (D.3.12) for the file is issued automatically by the system. The operation being performed is held up waiting for the retrieve to take place.
At the start of a MOP session, if the files have not been used for several days, it is sensible to use the RETRIEVE command explicitly to bring these files on-line. If the file is already on-line, the user will get a response indicating this. If a number of files are retrieved at the same time, this can be more efficient as the relevant magnetic tapes may only need to be loaded once.
If the user issues a command which causes an implied retrieve, he can save himself from being held up by pressing the BREAKIN key. This will not cancel the retrieve that has already been issued.
As files are brought on-line, it is necessary to remove other files to make space for them. This is done depending on the size of the file and how frequently it has been used. If a user knows that a particular file is no longer needed for quite some time, it is beneficial to the users as a whole if he calls the ARCHIVE command (D.3.14). This will ensure that this file rather than one still in use will be removed when space is next required on disc.
The operator can send messages to a MOP terminal by means of the BROADCAST command. These cannot be suppressed by the user and any requests by the operators should be obeyed as soon as possible. For example, the user may be asked to finish any work he is doing and LOGOUT. If he does not do this, it is possible that he may lose: the files that he is working on.
Messages can be sent to the 1906A operator using the DISPLAY command (D.5.6). For example:
DISPLAY 2, MY MAG TAPE IS WITH RECEPTION
In general, the 1906A operators should not be contacted except in real emergencies or if the user has useful information that they require.
It is sometimes necessary to cancel an operation from the MOP terminal. For example, the user may have issued a LISTFILE or a LISTDIR and the relevant information has been printed. Rather than wait until the end of the printing, the user may hit the BREAKIN key (he may need to do it twice) to cancel the previous command. At this stage, the user is in BREAK-IN context and he will be unable to obey certain commands. Therefore, it is sensible to type QUIT or CONTINUE to return to normal context before continuing.
Local modifications to GEORGE allow the user to input, edit and manipulate files containing the full 128-character ASCII set instead of the standard 1900 64-character set. The use of these facilities is only recommended when the user has a definite need for the lower case alphabet. The four characters ACCEPT, BREAKIN, CANCEL and BACKSPACE (←) have their normal GEORGE meaning. As characters are input, they are translated into the ICL standard 3-shift representation. These shifts are defined as α, β and δ respectively. Characters on a shift include the standard upper case alphabet while β shift includes the lower case alphabet. The δ shift is rather special in that it only qualifies the following character. For both α and β shifts, once the shift character appears all the following characters are on the same shift until another α or β shift character appears. Consider the line:
This is UPPER Case
The internal form of this line will be:
TβHIS IS αUPPER CβASE
The line always starts in α shift. The shift characters are only added where necessary (except for δ shift).
To input a file containing both upper and lower case letters, the user must use a terminal capable of generating both alphabets. The form of the INPUT command is:
INPUT MYFILE (ALLCHAR) This is UPPER Case ****
The only printing characters on δ shift are ], \ and +. Once the character has been output, the previous shift applies.
The backspace key (←) can be used during the input of a file to perform local editing. However, the user must remember that the editing is being performed on the internal form of the line. Consider the line which has been input as:
This is UT←PPER C←case LOWER d←←case\←←.
The internal form of the line is:
TβHIS IS αUT←PPER C←βCASE αLOWER βD←←CASE δ\←←.
Once the local editing has been done, the line becomes:
TβHIS IS αUPPER βCASE αLOWER CASE.
Printing this line on a device producing both upper and lower case would give:
This is UPPER case LOWER CASE.
This may or may not be what the user expected! If the user is doing local editing, he must remember where the shift characters appear in the line and decide whether these need removing as well. A full definition of the 3-shift code is given in E.6.
Editing ALLCHAR files (Part G for full details of the EDITOR) using a terminal capable of generating upper and lower case letters is possible but the user has to be very careful. He must remember where the case shift characters appear in the line.
The editing commands themselves are no problem. The user is allowed to write TC, tC, Tc, tc and all are recognised, as the same command. However, if a string is being searched for, then it must correspond exactly to the one between the delimiters in the editing command, that is, the case shift characters must appear in exactly the same place.
Consider, for example, the line:
Hello Folks Thats All
This will be stored internally as:
HβELLO αFβOLKS αTβHATS αAβLL
The following searches will all move the pointer to the expected position:
T/Hello/ TC/T/ r/Folks/folks/
However, the following command will not work correctly:
t/Hello/
This will appear at:
βT/αHβELLO/
The string being searched for is αHβELLO and this does not appear at the start of the line. Similarly, the following command will fail:
T/llo/
This corresponds to:
T/βLLO/
Care should be taken that, after editing a line, the user does not leave odd shift characters in the record. Consider, for example, the command:
R/F//
The line will now contain:
Hello olks Thats All
However, if the line is looked at closely, it can be seen that it contains:
HβELLO αβOLKS αTβHATS αAβLL
If, at a later time, the editing command below was obeyed:
tc/o o/
This would not recognise the line above due to the hidden case shift characters between the two letters o.
If a line is listed by the W or L commands (G.3.5), it will appear in the GRAPHIC set of 64 characters. The original line would be printed as:
H]ELLO $F]OLKS $T]HATS $A]LL
This has the advantage that the shift characters α, β, δ can be seen as the characters $, ] and +. At ACL, some terminals print the character \ in place of $.
The internal code for each character is given in octal followed by the character.
| OCTAL | CHARACTER | OCTAL | CHARACTER |
|---|---|---|---|
| 00 | 0 | 40 | @ |
| 01 | 1 | 41 | A |
| 02 | 2 | 42 | B |
| 03 | 3 | 43 | C |
| 04 | 4 | 44 | D |
| 05 | 5 | 45 | E |
| 06 | 6 | 46 | F |
| 07 | 7 | 47 | G |
| 10 | 8 | 50 | H |
| 11 | 9 | 51 | I |
| 12 | : | 52 | J |
| 13 | ; | 53 | K |
| 14 | < | 54 | L |
| 15 | = | 55 | M |
| 16 | > | 56 | N |
| 17 | ? | 57 | O |
| 20 | Space | 60 | P |
| 21 | ! | 61 | Q |
| 22 | " | 62 | R |
| 23 | # | 63 | S |
| 24 | £ | 64 | T |
| 25 | % | 65 | U |
| 26 | & | 66 | V |
| 27 | ' | 67 | W |
| 30 | ( | 70 | X |
| 31 | ) | 71 | Y |
| 32 | * | 72 | Z |
| 33 | + | 73 | [ |
| 34 | , | 74 | $ |
| 35 | - | 75 | ] |
| 36 | . | 76 | ↑ |
| 37 | / | 77 | ← |
The 1900 3-shift character set is given below with the octal value followed by the character in the three shifts.
| CHARACTER | CHARACTER | ||||||
|---|---|---|---|---|---|---|---|
| OCTAL | α | β | δ | OCTAL | α | β | δ |
| 00 | 0 | 0 | TC7 | 40 | @ | _ | |
| 01 | 1 | 1 | DC1 | 41 | A | a | |
| 02 | 2 | 2 | DC2 | 42 | B | b | |
| 03 | 3 | 3 | DC3 | 43 | C | c | |
| 04 | 4 | 4 | DC4 | 44 | D | d | |
| 05 | 5 | 5 | TC* | 45 | E | e | |
| 06 | 6 | 6 | TC9 | 46 | F | f | |
| 07 | 7 | 7 | TC10 | 47 | G | g | |
| 10 | 8 | 8 | CNCL | 50 | H | h | |
| 11 | 9 | 9 | EM | 51 | I | i | |
| 12 | : | : | SB | 52 | J | j | |
| 13 | ; | ; | ESC | 53 | K | k | |
| 14 | < | < | IS4 | 54 | L | l | |
| 15 | = | = | IS3 | 55 | M | m | |
| 16 | > | > | IS2 | 56 | N | n | |
| 17 | ? | ? | IS1 | 57 | O | o | |
| 20 | Space | Space | TC0 | 60 | P | p | |
| 21 | ! | ! | TC1 | 61 | Q | q | |
| 22 | " | " | TC2 | 62 | R | r | |
| 23 | # | # | TC3 | 63 | S | s | |
| 24 | £ | £ | TC4 | 64 | T | t | $ |
| 25 | % | % | TC5 | 65 | U | u | ] |
| 26 | & | & | TC6 | 66 | V | v | ↑ |
| 27 | ' | ' | BEL | 67 | W | w | ← |
| 30 | ( | ( | FE0 | 70 | X | x | N2 |
| 31 | ) | ) | FE1 | 71 | Y | y | N3 |
| 32 | * | * | FE2 | 72 | Z | z | N4 |
| 33 | + | + | FE3 | 73 | [ | N1 | \\\ |
| 34 | , | , | FE4 | 74 | α | α | α |
| 35 | - | - | FE5 | 75 | β | β | β |
| 36 | . | . | SO | 76 | δ | δ | δ |
| 37 | / | / | SI | 77 | |||
The meanings of the control characters on δ shift are
TC0 Null TC1 Start of heading TC2 Start of text TC3 End of text TC4 End of transmission TC5 Enquiry TC6 Acknowledge TC7 Data link escape TC8 Negative Acknowledge TC9 Synchronous Idle TC10 End of transmission block DC1 Device control DC2 DC3 DC4 Stop IS1 Unit separator IS2 Record separator IS3 Group separator IS4 File separator FE0 Backspace FE1 Horizontal tab FE2 Newline FE3 Line feed FE4 Form feed FE5 Carriage return CNCL Cancel EM End of medium SB Substitute ESC Escape BEL Bell SO Shift out SI Shift in Nl National characters N2 National characters N3 National characters N4 National characters
