US3823389A

US3823389A - Data processor with selectable operating modes

Info

Publication number: US3823389A
Application number: US00254726A
Authority: US
Inventors: R Heitman; R Norris
Original assignee: Arthur D Little Inc
Current assignee: Arthur D Little Inc
Priority date: 1972-05-18
Filing date: 1972-05-18
Publication date: 1974-07-09
Anticipated expiration: 1991-07-09

Abstract

A word processing system incorporating a typewriter as an input/output terminal, a mass storage system such as a magnetic tape recorder/player for storing data, and a shift register connected as a buffer memory between the typewriter and the recorder/player. The system is operative in two basic modes. The first is a draft mode in which the typewriter is operable manually to write characters and generate corresponding signals which are transferred through the buffer to storage on tape or is operable in response to signals transferred from tape. The second is a final mode which differs in that there is no storage made of signals corresponding to characters written by manual manipulation of the typewriter. The system also includes skip/delete controls; a character key, a word key and a line key which, if operated when the system is in the draft mode cause deletion of the signals corresponding to the selected character, word or line from storage, and if operated when the system is in the final mode cause the typewriter to skip writing of the selected character, word or line without however altering the storage of the signals.

Description

United States Patent [191 Heitman et a1. July 9, 1974 DATA PROCESSOR WITH SELECIABLE OPERATING MODES 57] ABSTRACT [75] Inventors: Richard E. Heitman, Acton;

Richard C. Norris, Belmont, both of Mass.

[ 73] Assignee: Arthur D. Little, Inc., Cambridge.

Mass.

[22] Filed: May 18, 1972 [21] Appl. No.: 254,726

[52] US. Cl. 340/1725, 197/19 [511 Int.Cl. G06f3/10,G11b 13/00 [58] Field of Search 340/1725; 197/19, 20

[56] References Cited UNITED STATES PATENTS 3,260,340 7/1966 LOcklan ct a1 197/19 3,291,277 12/1966 Borrellietal 197/20 3,297,124 1/1967 Sims 197/19 3,490,004 1/1970 Ross 340/1725 3,501,747 3/1970 Bungard et a1. 340/1725 3,528,063 9/1970 Kolpek 340/1725 Primary Examiner-Paul J. Henon Assistant ExaminerPaul R. Woods Attorney, Agent, or FirmSchiller 8L Pandiscio A word processing system incorporating a typewriter as an input/output terminal, a mass storage system such as a magnetic tape recorder/player for storing data, and a shift register connected as a buffer memory between the typewriter and the recorder/player. The system is operative in two basic modes. The first is a draft mode in which the typewriter is operable manually to write characters and generate corresponding signals which are transferred through the buffer to storage on tape or is operable in response to signals transferred from tape. The second is a final mode which differs in that there is no storage made of sig nals corresponding to characters written by manual manipulation of the typewriter.

The system also includes skip/delete controls; a character key, a word key and a line key which, if operated when the system is in the draft mode cause deletion of the signals corresponding to the selected character, word or line from storage, and if operated when the system is in the final mode cause the typewriter to skip writing of the selected character, word or line without however altering the storage of the signals.

9 Claims, 14 Drawing Figures MLHN CONTROL 54 28 22A i 5555 ADDRESS t Y l l. .I LOGIC DISDLAY 72 1 70 l l BUFFER l WRTE CONTROL CONTROL l LOGTC 75 I l 50 l 52 l 64 56 TAPE l CONTROL. I asst; L 2531f T 5 l LOGlC F MEMORY MOtTrPtExm CWLUWS 1 l tNPUT/OUTPUT J 5 DATA PRINTER I I {60 STORAGE l r L PRINT L FNPUT READ J l CONTROL -3- DEMULTB- DATA LOGIC I PLFXEP CtRCUITS l I 66 l 74 63 I l L I a J t l MARGIN J READ READ J ADJUST CONTROL ADDRESS J LOGtC LOGIC CIRCUWS PATENTED I- 91974 3.823.389

WEI 01 HF 15 FIG. I.

Pmemmm emu sum 02 ur15 PATENTED 9!!!" 3,823,389

mm 03 ur1s PATENTEDJUL 91am SHEU 05 0F 15 -NlOFN LIFO-(Illa) 2 E mu um SE woou Q05 Ho Kim mm Sim $3 $5 9: m

PATENTEII 91974 3.823.389

sum "as or 1s J C K R2 224 R MAIN 226 22 R f DATA r MU LTI- PLEXER ENABLE WRITE CLOCK 232 STATE 2/2 2/7 a COUNTER READ/WRITE HEAD ENABLE READ M CASSETTE COUNTER I 2 4 BINARYTO-OCTAL CONVERTER 5 4 3 2 I O ICC RECTIFIER AND SHAPER RECTIFIER AND SHAPER SHIFT REGISTER DEMULTI- PLEXER PATENTED 3.823.389

sum 10 or 15 FORCE SP FORCE BSP FORCE CR ENABLE GATES PRINT MODE CIM PIM

ANY FUNC- TION FROM KEYBOARD DELAY PULSES ESP ESP 2 ENABLE OPERATOR c1 T AB 5; TAB GATES A DECODEF? g TABS E TABCL TABCL g 1 1 & E R2 ENABLE R2 (I R A LTJJRZA GATES 2 5 w R5 R5 6 E T1 T1 32' O T T 2 o 2 2 O F S E PARITY CHECKER PATENTED 91974 sum 11 nr 15 0 Q 71 PRINT MODE #3 5 C 6 I44 30] D Q NORMAL 2oI SHIFT CRAT 8?;322 320 I/ TO TYPE IN 29885 CELL 326 NORMAL INSERLO 3H CYCLE INSERT 302 MODE 3 D Q 20! SHIFT D Q R INSERT I c 6 TIR EU NCTION OVERFLOW FROM K/

B

3,3

0 PIM 306 TERMINATE SHIFT 344 2? K 342 HUNTER I Q xf aaa L9 340 R 6 DELETE CLEAR BUFFER F/G. l0.

PATENTEUJUL 3.823.389

MN 12 (if 15 R2 T R A- SHIFT R5 REGISTER m DEMULTI- PLEXER 2 4 46 368 8* I 262 FORWARD] L 359 I 354 370 BCD 362 I 574 COUNTER 56 47 5721i 35a 3 376 I I l I /360 B K CONVERTER LO as4 ft 378/ O 77 DISPLAY fza MOTOR DRIvE 366 CIRCUITS r READ/WRITE 238 M CASSETTE HEAD DATA PROCESSOR WITH SELECT ABLE OPERATING MODEQ This invention relates to data processing, recording and printing apparatus, and more particularly to electronically controlled data recording and printing systems employing a keyboard-operated printer as in input/output terminal.

A large number of systems are known in which data entered on a keyboard-operated printer are encoded and stored on a record storage medium, the process being reversible so that the information stored on the record medium can be decoded and printed by the printer. It is also known to record the coded data on a wide variety of recording media such as magnetic tape or cards, punched tape and the like. The system enjoying the widest use, perhaps due to its versatility, is the type described, for example, in US. Pat. Nos. 3,297,124, 3,260,340, and 2,217,!50 among many others. This latter system is particularly adapted for use with printers of the type disclosed in US. Pat. No. 2,919,002 issued to L. E. Palmer.

The Palmer patent describes a device including a single element printing head having all of the characters of a type font, each being positioned at a unique location on a globular surface of a single printing head. The head is mounted for movement in a path parallel to a platen which can only rotate in a direction perpendicular to the path of motion of the head. The Palmer device selects a character by tilting and rotating the globular element so that a selected character is positioned directly opposite the platen, the selection of the character being responsive to the depression of one of a plurality of keys on a keyboard.

While data processing and recording systems employing the Palmer-type printer have been commercially successful, it has been found that they suffer from certain limitations. For example, in such systems, equipment and record media are relatively quite costly. In addition, some aspects of such systems are somewhat inconvenient to use.

This invention relates particularly to improvements in word processing systems which lead to more efficient use of machines, such as Palmer devices or other writing devices, magnetic data recorders and the like assem bled for form a data processor-recorder-printer. To this end it is important to provide basic machine operating modes which are the most convenient to use in normal applications of the processor-recorder-printer.

Typically, known word processing systems have three basic operating modes. In the first or Record mode, data typed on a keyboard is recorded in a mass storage means. In the second or Play mode, data is retrieved from a mass storage means and can be displayed on a printer or other output device. ln the third mode (Adjust), data can be retrieved and displayed with an automatic adjust mechanism in operation controlling the right-hand margin of the display. These three modes are convenient in use except when data is being retrieved and edited, or otherwise modified. On such occasions, the user must switch frequently between the Record mode and the Play mode. When systems of the type described are in the Play mode, it is normally permitted to type data at the keyboard when the system is otherwise inactive. In such cases, the typed data will be displayed on the printer or other output device, but will not be recorded in the mass storage means.

This invention describes a word processing system with two basic operating modes. In the first operating mode, hereinafter referred to as the Draft" mode, data storage (recording) and data retrieval and display (writing) are both pennitted. In the second operating mode, hereinafter known as the Final" mode, data storage is not pennitted, and data display is preferably under the influence of a right-hand margin adjust mechanism. Thus in essence, the Draft mode of operation of the present invention combines the operations of both the Record and Play modes described above in connection with a typical prior art word processing system. As recording and playing can both occur in the Draft mode hereinafter described, data can be edited or otherwise modified without requiring the user to switch between one operating mode and another.

In copending application Ser. No. 254,727 filed May 18, 1972 and assigned to the same assignee as this present application, there is disclosed a word processing system incorporating an input/output printer, a buffer memory and a mass storage means. The input/output printer is conveniently a typewriter such as is described in US. Pat. No. 2,919,002 so that when data are retrieved from the mass storage means, via the buffer memory, they are displayed by being printed out lineby-line on a sheet. The word processing system described in said copending application permits the operator to insert new data at any point in a block of data retrieved from the mass storage means, and to delete (i.e., permanently to eliminate or expunge from a record or memory) data between two points in a block of data retrieved from the mass storage means. Editing changes of this nature are normally recorded in the mass storage means, but such activity is permitted only in the Draft operating mode. In particular, controls are provided which permit the selective deletion of a character, a word, or a line, when the machine is in the Draft mode. When the above word processing system is in the Final mode of operation, the same controls provide the ability to selectively skip over a character, a word, or a line. Skipping over data does not involve a process of recording new data in the mass storage means, and can therefore be permitted in the Final mode. Skipping does not erase the data from the record stored in the buffer memory, or mass storage means, but simply prevents, at least at the time, the printing or display of the skipped data. In addition, it is not normally needed to skip data when operating the system in the Draft mode: thus, it is convenient to provide the delete and skip features with a single set of controls. Preferably, indication is provided to show whether operating a control will cause deletion or skipping of data.

Additional controls are provided to cause recorded data to be displayed or printed on the output device. In the embodiment to be described, five such controls are provided: play character, play word and play line controls cause the next recorded character, word or line to be displayed; a play auto" control causes continuous playing until the end of a document or some other condition is encountered; and a stop play control prevents any further data being displayed.

In the following description, it will be apparent that to play a word, for example, it is only necessary to operate the play word control regardless of whether the word processing system is in the Draft or Final mode.

In a typical prior art word processing system, the operator must first place the system in the Play mode, then select whether a character, word or line is to be played, and finally operate a Start control.

It is an object of this invention to provide a word process-system comprising an input/output device and a mass storage means having two basic operating modes. It is a further object of this invention to provide such a system wherein the first operating mode permits the recording of data in the mass storage means, the retrieval of data from the mass storage means, and the display on an output device of data retrieved from the mass storage means, and the second operating mode permits only the display of retrieved data, preferably under the control of a right-hand margin adjust mechamsm.

It is yet another object of the invention to provide such a system wherein a single control is used to either delete or skip a character in the retrieved data, depending upon a selected operations mode of the system. Yet another object is to provide such a single control system wherein if the system is in the first operating mode, the character can be deleted, and in the second operating mode it will be skipped. It is a further object of this invention to provide a like means for selectively deleting or skipping a word, and for deleting or skipping a line.

Other objects of the invention will in part be obvious and will in part be apparent hereinafter.

The invention accordingly comprises the apparatus possessing the construction, combinations of elements, and arrangement of parts which are exemplified in the following detailed disclosure, and the scope of the application of which will be indicated in the claims.

For a fuller understanding of the nature and objects of the present invention, reference should be had to the following detailed description taken in connection with the accompanying drawings wherein:

FIG. I is a perspective illustration of the typewriter encoupled console embodying the principles of the present invention:

FIG. 2 is an enlarged view of the console of FIG. 1 showing various control buttons, displays and other elements;

FIG. 2A is a perspective view of a standard tape cassette illustrating in phantom, the organization of information on the tape according to the principles of the present invention;

FIG. 3 is a block diagram illustrating the organization of the invention;

FIG. 4 is a block diagram showing details of the keyboard interface logic of FIG. 3',

FIG. 5 is a block diagram showing details of the buffer memory of FIG. 3;

FIG. 6 is a logic diagram partly in block form illustrating a clocking control system forming part of the buffer control of FIG. 3;

FIG. 7 is a logic diagram partly in block form illustrating output multiplexer, input demultiplexer, and read and write circuits shown in FIG. 3;

FIG. 8 is a timing diagram illustrating the operation of elements of FIG. 7;

FIG. 9 is a logic diagram partly in block form, showing the print control logic system of FIG. 3;

FIG. 10 is a diagram illustrating some logic employed in the main control of FIG. 3 for controlling clocking of the buffer memory;

FIG. 11 is a diagram, partly in block form, showing address display logic coupled with the control console;

FIG. 12 is a diagram illustrating logic in the main control of FIG. 3;

FIG. 13 is an additional logic diagram illustrating the main control of FIG. 3; and

FIG. 14 is a logic diagram partly in block form showing part of the margin adjust logic of FIG. 3.

To achieve the foregoing and other objects, briefly the present invention employs an input/output writing device, a mass storage means, and a main buffer memory, typically a shift register, for selectively transferring data between the writing device and the mass storage means. Means are provided for controlling the transfer of data so that the system operates in either the Draft or the Final mode.

The operator of the system will normally create an initial draft of a document in the Draft mode, so that the characters making up the document are recorded in the mass storage means. The operator will subsequently make any necessary editing changes or other modifications in the same Draft mode, so that the modifications are recorded in the mass storage means. In this way, the mass storage means is used to accumulate the characters needed to display or print out an errorfree document. The operator will normally generate one or more final copies of the document in the Final mode so that the right-hand adjust mechanism can compensate for any changes in recorded line length caused by the editing procedures. It is, of course, permissible for the operator to generate a final copy of a document or part of a document in the Draft mode. Such a procedure is preferable if the displayed line format is complex, as in tabular matter.

When the operator is editing a recorded document in the Draft mode, the delete and insert features of the above word processing system will normally be used, in addition to other procedures described in the above mentioned copending application.

The two operating modes which form a basis for this invention can be described in another manner. In the Draft mode the typewriter keyboard is active. That is, any characters or typewriter functions (space, backspace, etc.) typed by the operator will be recorded in the mass storage means. In the Final mode, the keyboard is inactive. That is, data typed will not be recorded in the mass storage means, although it may be displayed on the output device.

Referring now to the drawings, there is shown in FIG. 1 a preferred arrangement of equipment in which the invention is incorporated. The apparatus of the invention includes an input/output printer 20 interconnected by an electrically conductive cable 21 to a control con sole unit 22 for controlling recording, reproducing, and editing. Printer 20 typically includes a manually operable keyboard 23 for controlling a single head printer of the Palmer-type which has been adapted (for example by being emplaced on a baseplate 24 which is capable of detecting the condition of the latch and cycle shaft switches in the printer and also having solenoids capable of driving the latches and cycle shaft of the printer) for producing an output indicative of the condition of those switches. Such a baseplatc is described in U.S. Pat. Nos. 3,452,851 and 3,453,379 issued to L. Holmes, Jr. In printers of the Palmer type each character is automatically encoded when typed. When such a printer is combined with a Holmes type baseplate the combination will be capable of translating or interconverting formation of typed characters and performance of printing functions with corresponding coded character and function signals.

Unit 22 has a control panel 26 shown in more detail in FIG. 2, the panel including a spring-loaded, normally closed cassette door 27 which is moveable so that a magnetic tape cassette 240 (shown in more detail in FIG. 2A) can be loaded into a tape transport mechanism located behind the door. Adjacent door 27 is a display 28 for indicating a record number corresponding to the position of a data location on the tape 18 in a cassette 240 which may be loaded into the machine. On control panel 26 are also a number of keys or buttons and display lights associated with data entry, editing and playback. The system of the invention is intended to have three basic operating modes, a draft mode, a final mode and an insert mode. To provide for selection of the mode of operation of this system there are provided a Draft button 30, a Final button 31, and an Insert button 32. To provide for control of printing out onto the printer of a character, word, or line from storage, either while the system is in draft or final mode, there are included a Character button 33, a Word button 34, and a Line button 35, plus an Automatic button 36 for allowing the system to print continuously. An On button 37 is also provided for starting the system. Stop button 38 is included for stopping any printing operation by the machine. The deleting or skipping of characters, words and lines respectively is provided by manipulation of Character, Word and

Line buttons

45, 39 and 40.

A brief description of the functional consequences of the operation of the various buttons on control panel 26 will be helpful in understanding the detailed structural description of the device. It is intended that the system be capable of both recording data onto a cassette 240 or playing data from a cassette 240 onto printer when operating in the draft mode. Specif- -cally, it is intended during draft mode operation that any data entered by manipulation of keyboard 23 of printer 20 should be stored in a magnetic storage or record in the system with any previously recorded characters being overwritten by new data being stored at the same data locations. In order to accomplish this end one need merely start the system, select the record location, press Draft button 30 and proceed to type in data on the keyboard. To cause the data thus stored to actuate printer 20 and therefore to be typed out, it is only necessary to return to the beginning of the stored data to push Character button 33 to obtain print out of a single character, to push Word button 34 to obtain a single word, to push Line button 35 to obtain a single line, or to push Automatic button 36 to permit the entire stored data to be reproduced on printer 20.

If one should now press Final button 31, the system is conditioned so that no storage of data manually typed or entered on printer 20 can occur, but that only the data stored in the machine can be played out on printer 20. When playing in the Final mode it will be later seen that an automatic right margin control system operates. The Draft and Final modes of operation are mutually exclusive and the system provides that if either the Draft or Final buttons are pushed, the machine is switched from the one to the other mode of operation.

Depression of Insert button 32 while the system is in the Final mode will be ineffective, i.e. will not in any sense allow the machine to operate other than in normal Final Mode operation. On the other hand, if the In sert button 32 is depressed while the system is in the Draft mode, the system switches to an lnsert Mode of operation, and if desired, visual indication can be given that the machine is in an lnsert Mode, as by lighting lnsert button 32 or the like. The lnsert Mode is intended to provide an operation such that data entered on printer 20 by manual operation of the keyboard 23 will be inserted into storage, up to a limit, without overwriting or othenivise destroying previously stored data. Only typing and recording can take place while in the Insert Mode since pushing any other buttons (except the Draft or Final buttons) on the control panel will cause the machine to trip out of the Insert mode and revert to the Draft mode. If lnsert button 32 is pushed again, the system will switch out of the Insert Mode back to the Draft Mode and, of course, any visual indication of lnsert Mode operation will terminate. If Final button 31 is pressed, the system will switch to Final mode operation.

The play or

print buttons

33, 34, 35, 36 or 38 control the extent to which data will be read out of storage, either in Draft or Final mode operation, and displayed on printer 20. Each time Character button 33 is pushed, the next character in storage will be read out on printer 20. Similarly, depression of Word button 34 or Line button 35 will cause the next word or line in storage to be read out on the printer. When the Automatic button 36 is pushed, the system will cause the printer 20 to type out the data in storage continuously until some stopping command occurs. The latter can be obtained by pressing Stop button 38, or by certain special conditions which will be described hereinafter.

Step Right and Step

Left buttons

41 and 42 control the shifting of data in storage. Each time either is pushed the data in storage is shifted by one character in the appropriate direction and the single print head 16 or carrier on the printer 20 similarly steps. In this

respect buttons

41 and 42 actuate the print head [6 to move in the same manner as the space bar and backspace key on the printer keyboard 23, with certain exceptions as will be explained later. Preferably, if one of the

buttons

41 and 42 is held down, repetitive action is initiated so that the system steps sequentially character by character.

As described, there are three delete/

skip buttons

45, 39 and 40. When the system is in Draft mode depression of these buttons will serve to delete a recorded character, word or line from storage. When the system instead is in the Final mode, these buttons act as skip buttons which cause the system to skip the appropriate character, word or line in storage without overwriting or otherwise destroying the skipped data. Because the functioning of these buttons to cause either deletion or skipping depends upon the mode in which the system is then operating, means are provided in the form of visual indicating lights 43 and 44 which respectively light up to indicate the nature of the function of the buttons, i.e. delete or skip as the case may be.

There are two buttons for controlling tape motion, a Tape Forward button 46 and a Tape Back button 47. These are preferably of the spring-loaded type and each has a first or up position and a second or down position. Pushing either of the

tape buttons

46 or 47 to its down position causes the system to move the tape 18 either back or forward (as the case may be) to the be ginning of the next of a number of predetermined data blocks 19 or stations on the tape 18. This motion from predetermined station to predetermined station on the tape 18 will continue as a smooth sequence until the appropriate button is released. After release of the button, the motion of the tape 18 in the cassette 240 will continue until the next predetermined station on the tape 18 is reached, at which time the motion of the tape 18 is stopped. Similarly pushing either

buttons

46 or 47 to their up position causes the system to shift to a fast forward or fast rewind movement (as the case may be) during which the tape winds continuously. Fast winding due to pushing the Tape Back button 47 to its up position will continue until the button 47 is released, at which point the system then shifts to slow forward speed and continues to move the tape until the next predetermined station on the tape is located. A similar operation in the opposite direction is effected by manipulation of the Tape Forward button.

In the preferred embodiment the cassette tape is at least a two track (25 and 29) tape, and two read/write heads, one for each of tracks 25 and 29, (or a single two-channel head such as head 238) are incorporated into the system. One of the tracks, 25, of the tape is for the data to be stored. The other tape track 29 is intended to contain data addresses 48, preferably in the form of coded conversions of sequentially numbered three decimal digits, each data address 48 being physically located substantially adjacent the beginning of a data block l9 on track 25. Thus, when the tape is moved either forward or back in the cassette, circuitry associated with the address read/write head and the record number display 28 will cause the latter to be appropriately indexed each time an address corresponding to a data block 19 or record moves past the read head. lf desired, one can provide an erase mechanism associated with the tape transport mechanism and the control panel so as to erase selectively all data from the tape 18, and also if desired to regenerate the addresses on the tape 18.

Also in the preferred embodiment, associated with the control panel are a number of visual indicators or special lights 49 in addition to the delete/skip light and insert indicator light discussed earlier. These additional lights will be described later hereinafter. Similarly, a number of audio signal devices to indicate certain conditions of the apparatus can also be provided and will be described hereinafter.

The operation of the device thus described can be advantageously described in connection with a typewriter as an example of the printer. There are three basic situations to be described:

I. Basic entering of data through the typewriter keyboard, i.e. recording an initial draft;

2. Insertion, deletion and other operations made on data after entry of the latter, i.e. editing; and

3'. Data retrieval, i.e. typing of final copy.

in order to record data initially, the operator will first activate the typewriter and also will depress button 37 to turn on the remainder of the system. The operator should first set margins and tabs on the typewriter as desired although one or more embodiments of the invention may include the ability to set and clear tabs on the basis of prior stored information. Then a magnetic tape cassette 240 is placed in the carrier behind door 27 and the operator then depresses button 30 to place the system in the draft mode of operation. The position of the tape 18 in the cassette 240 will be indicated by the address displayed at display 28. If the cassette 240 is not rewound and it is desired to start from the beginning of the cassette, the latter can be rewound by pushing Tape Back button 47 to its up position and waiting until rewind is completed. lf the operator wishes to start beyond previously recorded material that is to be preserved, the tape 18 can be moved with

buttons

46 and 47 until the appropriate address is noticed at display 28.

Hereafter, recording in the Draft mode is accomplished automatically merely by typing the desired information on the typewriter keyboard 23. Each time the operator types a Carrier Return, the data associated with the preceding typed line is then transferred from the buffer memory of the system onto magnetic tape 18. If the operator observes that a wrong key has been struck, correction can be made by depressing the Step Left button 42 which causes the typewriter to automatically backspace. When the typewriter has been backspaced to the error, the operator can strike over the error with the correct character key. To get back to the point where recording has been interrupted, the Step Right button 41 can be depressed, or as will appear later, one can play out the intervening material which has been recorded, or lastly one can retype the intervening material and rerecord it.

If the operator wishes to underscore a word upon entry, the word can be typed and then, using the regular backspace key on the typewriter keyboard which will provide a recorded backspace, the typewriter should be backed up to the beginning of the word. The word can then be underscored, the underscoring being recorded also.

When the operator has completed the draft, a Stop Code should be entered. The Stop Code is generated by depressing the shift key and striking Stop button 38 on the control panel.

Editing of a draft can be done in three basic ways:

l. A new draft can be generated in the Draft mode of operation, combining the desired parts of the old draft with typed and recorded corrections;

2. Only specific lines requiring editing can be modifled; or

3. A final copy can be generated in the Final mode of operation with corrections being entered on the copy as the document is printed, without recording the corrections.

Normally, the first approach would be used especially if further author revisions are anticipated. The third approach is appropriate if only final, minor corrections are to be made and a final copy is desired.

In generating a new draft, the following situations are likely to be encountered. First, one can edit simple typographical errors by playing back the tape 18 in the Draft mode, by first striking any one of

buttons

33, 34, 35 or 36. This will cause the material recorded on the cassette to be played back on the typewriter, assuming of course that the cassette 240 has been rewound to the appropriate starting position. The material is then played up to but not through the error and the error is corrected by overstriking. Overstriking using the keyboard 23 will automatically erase the erroneous material in the appropriate place.

Claims

1. Data recording and printing apparatus comprising in combination: input/output writing means for writing characters and for generating coded signals corresponding to said characters, said writing means including a manually operable keyboard for initiating said writing of characters and said generating of corresponding coded signals, and means for operating said writing means in response to coded signals to provide writing of characters independently of said keyboard; mass storage means coupled to said writing means for receiving, storing and returning coded signals; means for controlling transfer of coded signals between said writing means and said mass storage means, and including selectively operable means for initiating transfer of coded signals from said mass storage means to said means for operating so as to cause said writing means to write characters corresponding to the coded signals transferred from said mass storage means to said means for operating and; means for operating the other aforesaid means in a first mode wherein manipulation of said keyboard causes said writing means to write characters and generate signals which are transferred to said storage or alternatively manipulation of said means for initiating transfer causes coded signals to be transferred from said mass storage means and written as corresponding characters by said writing means, means for operating said other aforesaid means in a second mode wherein manipulation of said keyboard causes said writing means to write characters but the transfer of said corresponding coded signals to said mass storage means is blocked or alternatively manipulation of said means for initiating transfer causes coded signals to be transferred from said storage means and written as corresponding characters by said writing means, and mode selecting means for mutually exclusively selecting between operation of said other aforesaid means in either said first or said second mode.

2. Apparatus according to claim 1 wherein said means for controlling transfer includes a buffer memory for temporarily storing and selectively transferring signals between said writing means and said mass storage means.

3. Apparatus according to claim 2 wherein said writing means is adapted to form said characters on a record medium in line of characters and line-by-line format, anD including: means for determining the predetermined respective characters to which signals stored in said buffer memory, and means for controlling said writing means when said apparatus is in said second mode and said coded signals are being transferred from said storage means to said writing means, so as to compel said writing means alternatively to commence a new line of characters when signals corresponding to said respective characters are found at said positions, or to stop operation of said writing means when said signals corresponding to said respective characters are not found in said positions.

4. Apparatus according to claim 2 wherein said writing means comprises a typewriter.

5. Apparatus according to claim 2 wherein said mass storage means comprises a magnetic tape recorder/player.

6. Apparatus according to claim 1 wherein said writing means is adapted to form said characters on a record medium in a line of characters and line-by-line format, and said apparatus includes first, second and third controls, selectively and mutually exclusively operable when said apparatus is in said first mode, for expunging respectively from storage a single selected signal corresponding to one character, a selected sequence of signals corresponding to a word, and a selected series of signals corresponding to an entire line of words.

7. Apparatus according to claim 6 wherein said first, second and third controls are mutually exclusively operable, when said apparatus is in said second mode, for preventing transfer of coded signals to said means for operating said writing means so that respectively said writing means skips writing a character corresponding to a single selected signal, skips writing a word corresponding to a selected sequence of signals, and skips writing an entire line of words corresponding to a selected series of signals.

8. Apparatus according to claim 7 wherein each of said first, second and third controls comprises a manually operable key.

9. Apparatus according to claim 7 including means for indicating if said controls are operable in either said first or said second mode.