JPH09295432A - Printer and print controlling method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a printer capable of easily specifying a page where the overrun is generated, and a print controlling method. SOLUTION: Whether the memory capacity can be insufficient is predicted when print data are inputted from a host 3000, and the inputted print data are developed to bit map data to be stored in a plotting memory defined by a RAM 19. According to the prediction result, a message to show the overrun generation is overlaid to the bit map data after bit mapping so that the message is outputted to a recording paper where the generation of the overrun is expected. Then the message is printed out onto the recording paper, using the bit map data developed and stored in the RAM 19.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a printer device and a print control method, and more particularly to a printer device and a print control method capable of bidirectional communication with a host computer.

[0002]

2. Description of the Related Art Conventionally, a page printer such as a laser beam printer divides print data corresponding to one page of recording paper into several parts (the divided area or data to save memory capacity of a printer controller). , Called a band), and the bitmap was expanded to the bitmap memory in band units. Therefore, before the bit map expansion of the print data for one page is completed, the recording paper is supplied and the print output operation of the page printer is started.

On the other hand, because of the mechanism of the page printer, once the print command is issued, it is impossible to stop the paper transport mechanism of the printer on the way. When an overrun occurs such that an image cannot be recorded or only the recording paper is conveyed because the bitmap data is not transferred, an error message is displayed on the printer operation panel. Also, when a normal error occurs, the printer control unit temporarily suspends the print processing of the next page and waits for the reception of an error cancellation command when the output of the corresponding page is completed, or the automatic error skip function is activated. If the printer is equipped with the printer, even if an overrun occurs, the print process is not interrupted, and it is possible to select whether to continue the print process of the next page.

[0004]

However, in the above-mentioned conventional example, when the automatic error skip function is used, the print processing may not be interrupted. Therefore, especially when the print output for a very large number of pages is performed. However, there is a problem that it is impossible to know which page the overrun occurred in the print output result.

The present invention has been made in view of the above conventional example, and an object of the present invention is to provide a printer device and a print control method capable of easily specifying a page in which an overrun has occurred.

[0006]

In order to achieve the above object, the printer device of the present invention has the following structure.

That is, input means for inputting print data from the host, and expansion means for expanding the print data input by the input means into bitmap data,
A storage unit that stores the bitmap data, an output unit that prints out on a recording medium using the bitmap data stored in the storage unit, and a prediction unit that predicts whether a shortage of capacity of the storage unit is likely to occur. According to the result of the prediction by the predicting means, the message is bit-mapped and overlayed on the bitmap data so as to output a message indicating that the over-run has occurred to the recording medium in which the over-run is expected, or A printer device comprising: a notification unit that notifies the host of the occurrence of the overrun and the information of the page of the recording medium in which the overrun occurs by transmitting the overrun to the host. Prepare

According to another aspect of the present invention, there is provided a print control method in print output to a recording medium, comprising an input step of inputting print data from a host, and expanding the input print data into bit map data to obtain a storage medium. And a predicting step of predicting whether or not a capacity shortage of the storage medium is likely to occur; The message is bitmapped and overlayed on the bitmap data so as to output the message shown, or transmitted to the host together with the fact that the overrun has occurred and the information on the page of the recording medium where the overrun has occurred. A notification step for notifying the occurrence of the overrun, and Bitmap data using the provided print control method characterized by an output step for printing out on the recording medium.

[0009]

According to the present invention having the above-described structure, when the print data is input from the host, the input print data is expanded into bitmap data and stored in the storage medium, the capacity of the storage medium is likely to be insufficient. Whether or not it is predicted, and according to the prediction result, the message is bitmapped and overlayed on the bitmap data so that a message indicating that the overrun has occurred is output to the recording medium where the overrun is expected, or Notifies the host of the occurrence of an overrun and the information of the page of the recording medium on which the overrun occurs and notifies the host of the occurrence of the overrun, and uses the bitmap data stored in the storage medium to record the recording medium. It works to print out to.

Here, the print data includes PDL data, and the PDL data is interpreted by an interpreter. Further, for example, the capacity of a storage medium such as a RAM is smaller than the data amount of bitmap data corresponding to one page of the recording medium.

A printer engine for forming an image according to an electrophotographic system or an inkjet system can be used for print output.

Further, it stores bitmap data,
For example, a large-capacity auxiliary storage unit such as a hard disk may be provided, and bitmap data stored in a storage medium such as a RAM may be moved to the auxiliary storage unit according to the above prediction result. And during that move,
A storage area larger than the storage capacity of a storage medium such as a RAM is secured in the auxiliary storage means. Further, even if the moving means stores the bitmap data stored in the storage medium such as the RAM in the storage area of the auxiliary storage means such as the hard disk, when the capacity of the storage area is insufficient for the bitmap expansion, Alternatively, control may be performed so as to notify the occurrence of overrun.

A preferred embodiment of the present invention will be described in detail below with reference to the accompanying drawings.

FIG. 1 is a block diagram showing the configuration of a printer system which is a typical embodiment of the present invention. This system includes a host computer (hereinafter, referred to as a host) 3000 that generates print data and a printer 150.
0 and both are connected by a printer cable 21. The connecting means may be not only a printer cable but also a network such as a LAN, or a system configuration in which a plurality of hosts share a printer in a LAN environment.

The host 3000 shown in FIG. 1 executes document processing in which graphics, images, characters, tables (including spreadsheets, etc.) are mixed based on the document processing program stored in the program ROM 3b. The CPU 1 is provided. The CPU 1 is a keyboard (KB) 9 connected to the CPU bus 4 via a keyboard controller (KBC).
A pointing device (not shown), a CRT 10 controlled via a CRT controller (CRTC) 6, a boot program controlled via a memory interface (I / F) 7, various applications, phones and data, user files, An external memory 11 for storing driver software for a printer device, an edit file, or the like, or
Each device such as an external storage device such as a hard disk (HD) 3d and a floppy disk (not shown) is comprehensively controlled.

The program ROM 3b stores a control program executed by the CPU 1, an interpreter for interpreting PDL, etc., the font ROM 3a stores font data used in document processing, and the data ROM 3c stores Various data such as forms and fixed phrases used when performing document processing are stored. On the other hand, RAM2
Is used as a work area or the like when the CPU 1 executes various controls and processes. The CPU 1 is, for example, RA
The outline font is expanded (rasterized) to the bitmap memory defined in M2, and the CRT is executed.
10 is used to enable "WYSIWYG" processing with a system user. Further, the CPU 1 opens various windows registered on the basis of commands designated by a mouse cursor (not shown) or the like for icons and menus displayed on the CRT 10 and executes various data processing.

A printer controller (PRTC)
8 is a printer 1500 via the printer cable 21.
And executes a communication control process with the printer 1500 according to a predetermined bidirectional communication protocol.

On the other hand, the printer 1500 controls the communication with the host 3000 and the host 30 as shown in FIG.
The printer 1000 includes a controller 1000 that performs image processing on the print data transmitted from the printer 00 and controls the operation of the entire printer, and a printer engine 17 that forms an image based on the print data and prints it out. In addition, the controller 1000 has an LCD, L
An operation panel 1501 including an ED and a keyboard is provided, and various settings and designations can be made through the operation panel interface (I
/ F) 23 to the printer. Further, the controller 1000 is configured to be able to execute various data processing by optionally connecting an external memory 14 such as an IC card for storing font data, emulation programs (control programs having different language systems), form data and the like. .

The external memory 14 is controlled by the memory interface (I / F) 20. Further, the external memory 14 is not limited to one, but a plurality of storage media such as an internal font, an optional font card, a memory storing a program for interpreting printer control languages of different languages, and the like can be mounted. May be.

The controller 1000 has a CPU 1
2 is provided, and the CPU 12 has a program ROM 13
control program or the like stored in b or the external memory 1
4 collectively controls access to various devices connected to the system bus 15 based on a control program stored in the printer engine interface (I / I).
F) An image signal is output as output information to the printer engine 17 connected via F16. Further, the CPU 12
Can communicate with the host 3000 via the input unit 18, and can notify the host 3000 of internal information of the printer 1500.

The font ROM 13a stores font data and the like used when generating output information, and the printer 150 performs a certain amount of print processing even when the external memory 14 is not mounted in the data ROM 13c.
Information and the like necessary for execution at 0 are stored. The RAM 19 is used as a work area such as an output information expansion area and an environment data storage area when the CPU 12 executes the control program, and the memory capacity is expanded by an option RAM connected to an expansion port (not shown). It is configured to be able to. In addition, not only normal RAM but also NVRAM 22 can be used for the expansion. Then, the print mode setting information from the operation panel 1501 may be stored in the NVRAM 22. Further, the NVRAM 22 stores various printer setting information set at the time of factory shipment, for example, a plug & play compatible device ID corresponding to the window 95, and the like.
It is also possible to mount a hard disk (HD) 3d capable of storing a large amount of information as compared with the above.

In the system thus constructed,
When the print data generated and output by the host 3000 is first transferred to the input unit 18, the CPU 12
Is an overrun occurrence based on the input data,
Alternatively, if there is a page expected to occur, a message is printed on the corresponding page. Further, when the controller 1000 predicts the occurrence of overrun during the print processing, it can notify the host 3000 that an error has occurred.

FIG. 2 is a printer device 1500 including a printer engine 17 for recording by adopting an electrophotographic system.
It is a side sectional view showing the internal structure of.

In FIG. 2, reference numeral 1500 denotes a laser beam printer (LBP), which forms an image on a recording sheet, which is a recording medium, based on a supplied character pattern or the like. 150
1 is an operation panel on which a switch for operation and an LED display are arranged, and 1000 is the LBP described in FIG.
A printer controller that controls the entire 1500 and analyzes character pattern information and the like.

The laser driver 102 is the semiconductor laser 10.
3 for driving the laser light 1 emitted from the semiconductor laser 103 in accordance with the input video signal.
04 is turned on / off. The laser beam 104 is swung right and left by a rotating polygon mirror 105 to scan on an electrostatic drum 106. Thus, an electrostatic latent image of a character pattern is formed on the electrostatic drum 106. After the latent image is developed by the developing unit 107 around the electrostatic drum 106,
Transferred to recording paper. A cut sheet is used as the recording sheet, and the cut sheet recording sheet is stored in the sheet cassette 108 mounted on the LBP 1500 and taken into the apparatus by the sheet feeding roller 109 and the conveying rollers 110 and 111.
It is supplied to the electrostatic drum 106.

In this way, the given print data is recorded and output on the paper.

In addition to the laser beam printer that forms an image according to the electrophotographic system described above as the printer engine, an inkjet printer that performs recording according to the inkjet system may be used as the printer engine.

FIG. 3 shows an ink jet printer IJRA.
3 is an external perspective view showing the outline of the configuration of FIG. In FIG.
The carriage HC that engages with the spiral groove 5004 of the lead screw 5005 that rotates via the driving force transmission gears 5009 to 5011 in conjunction with the forward and reverse rotation of the drive motor 5013 has a pin (not shown), 5003
And reciprocate in the directions of arrows a and b. On the carriage HC, an integrated type ink jet cartridge IJC containing a recording head IJH and an ink tank IT is mounted. Reference numeral 5002 denotes a paper holding plate, which applies a platen 5000 to the recording paper P in the moving direction of the carriage HC.
Press against Reference numerals 5007 and 5008 denote photocouplers, which are home position detectors for confirming the presence of the carriage lever 5006 in this region and switching the rotation direction of the motor 5013. Reference numeral 5016 denotes a cap member 5022 for capping the front surface of the recording head IJH.
Reference numeral 5015 denotes a suction device that suctions the inside of the cap, and performs suction recovery of the recording head through the opening 5023 in the cap. Reference numeral 5017 denotes a cleaning blade. Reference numeral 5019 denotes a member which allows the blade to move in the front-rear direction. These members are supported by a main body support plate 5018. It goes without saying that the blade is not limited to this form and a known cleaning blade can be applied to this example.
Reference numeral 5021 denotes a lever for starting suction for recovery of suction. The lever 5021 moves with the movement of the cam 5020 that engages with the carriage, and the driving force from the driving motor is controlled by a known transmission mechanism such as clutch switching. Is done.

The capping, cleaning, and suction recovery are configured so that the desired processing can be performed at their corresponding positions by the action of the lead screw 5005 when the carriage comes to the area on the home position side. As long as the desired operation is performed at the timing, any of the above can be applied.

FIG. 4 is a block diagram showing the configuration of the printer engine interface (I / F) 16 when a laser beam printer is used as the printer engine 17.

In FIG. 4, reference numeral 407 denotes a double buffer which interleaves bitmap data from a bitmap memory provided in the RAM 19, and 408 transmits a command (CMD) to the printer engine 17 or the status of the printer engine 17 ( A video interface (I / F) logic circuit for receiving STS), and a P / S converter 409 for converting parallel data transferred from the double buffer 407 into serial data.

FIG. 5 is a block diagram showing the arrangement of the control circuit of the ink jet printer IJRA controlled by the printer engine interface (I / F) 16. In FIG. 5, 1710 is a carrier motor for carrying the recording head IJH, and 1709 is a carrying motor for carrying the recording paper. Reference numeral 1705 denotes a head driver that drives the recording head IJH, and 1706 to 1707 are motor drivers that drive the carry motor 1709 and the carrier motor 1710, respectively.

In the circuit configured as described above, the print head IJH is driven according to the print data sent to the head driver 1705 via the printer engine interface (I / F) 16, and by another control signal,
The motor drivers 1706 and 1707 are driven to execute the recording operation.

The printer applied to the present invention is not limited to the laser beam printer and the ink jet printer, and is provided with a printer employing another printing method (a thermal printing method, a thermal transfer printing method) or a printing function. Needless to say, a copy machine can be used.

Next, the print control processing executed by the printer system having the above-described configuration will be described with reference to the flowchart shown in FIG. 6 and the memory allocation of the RAM 19 shown in FIG. Note that in this description, FIG.
It is assumed that a laser beam printer as shown in (1) is used as a printer engine. In addition, the RAM 19 shown in FIG.
The drawing memory 19c is smaller than the capacity of the bitmap data corresponding to one page of the recording paper in order to save the memory capacity, and this printer is assumed to perform the bitmap expansion in band units as described in the conventional example.

First, in step S501, the controller 1000 stores the print data sent from the host 3000 in a predetermined area of the RAM 19 (page memory 19a shown in FIG. 7). Next, in step S502, CP
The interpreter executed by U12 analyzes the print data described by the PDL command sent from the host 3000, converts it into intermediate data, and stores it in the intermediate object memory 19b shown in FIG. Further, in step S503, rasterization processing is performed based on the intermediate code to expand the bitmap data in the drawing memory (19c in FIG. 7) defined in the RAM 19.

Next, in step S504, it is predicted whether or not the capacity of the drawing memory 19c will be insufficient during the rasterizing process. This prediction is made, for example, by comparing the bitmap data amount based on the PDL data analysis result or the bitmap expansion rate (speed) to the drawing memory with the drawing memory capacity. Here, if it is determined that the overrun due to the memory shortage does not occur, the process is likely to step. If not, the process proceeds to step S50.
Proceed to 6 to continue the expansion process to bitmap data,
Further, in step S507, it is checked whether or not the bit map expansion for one band of the recording paper is completed. here,
If the expansion of the bitmap for one band has not been completed, the process returns to step S503, and if it is determined that the expansion has been completed, the process proceeds to step S508,
The printer engine 17 uses the bitmap-developed data.
Transfer to

Further, in step S509, it is checked whether the bit map expansion for one page of the recording paper and the data transfer to the printer engine 17 are completed. Here, if it is determined that the bitmap expansion for one page and the data transfer to the printer engine 17 are not completed, the process returns to step S503, and if it is determined that the expansion and transfer are completed, , The process ends.

On the other hand, if it is predicted in step S504 that an overrun due to lack of memory will occur, the process proceeds to step S505, the overrun message is expanded into a bitmap, and the data is expanded correspondingly. Overlay on the bottom of the page. And
Then, a process progresses to step S510.

Finally, in step S510, the bitmap-developed data is transferred to the printer engine 17, and the process ends.

Therefore, according to the embodiment described above,
In the print output process based on the PDL data from the host, if it is predicted that an overrun due to a memory shortage will occur, a predetermined message will be output to the relevant page, so that the device user can From the output, it is possible to easily find which page the overrun is occurring.

[0042]

Other Embodiments In the printer 1500 having the configuration shown in FIG. 1, when the controller 1000 is equipped with a hard disk (HD) 13d for storing a large amount of data, it is associated with overrun due to lack of memory. ,
Printer control processing as shown in FIG. 8 can be executed.

The processing will be described below. In addition,
In this description, the same processing steps as those already described with reference to FIG. 6 are designated by the same step reference numerals and the description thereof will be omitted. Here, only the processing characteristic of this embodiment will be described.

After the processing of steps S501 to S503, if it is predicted in step S504 that an overrun due to lack of memory will occur, the processing proceeds to step S70.
In step 5, it is checked whether or not there is a free area on the hard disk (HD) 13d. Here, when it is determined that there is a free area, the process proceeds to step S706, and the RAM 17
The data that is being bitmap-developed on the hard disk (H
D) Move to 13d and enlarge the drawing memory area. Then, the process returns to step S503. After that, the bitmap expansion is executed using the enlarged drawing memory area of the hard disk (HD) 13d.

On the other hand, if it is determined in step S707 that the hard disk (HD) 13d has no free space, the process proceeds to step S707, and the host 3000 is notified of overrun occurrence due to a memory shortage. Information with respect to the notification, and then the process proceeds to step S510. Note that step S707
In the above process, similarly to the above-described embodiment, a process of expanding the message indicating the occurrence of the overrun into a bitmap and overlaying the message may be added.

Therefore, according to the embodiment described above,
Since the shortage of the drawing memory 19c of the RAM 19 is compensated by using the hard disk (HD) 13d, it is possible to continue the bitmap expansion without causing an overrun.
If the hard disk (HD) 13d has no free space, the host 3000 is notified to that effect.
The device user can specify the overrun page from the message displayed on the CRT 10 of the host 3000, for example.

Another object of the present invention is to provide a storage medium storing a program code of software for realizing the functions of the above-described embodiments to a system or apparatus, and to provide a computer (or CPU) of the system or apparatus.
And MPU) read and execute the program code stored in the storage medium.

In this case, the program code itself read from the storage medium realizes the functions of the above-described embodiment, and the storage medium storing the program code constitutes the present invention.

As a storage medium for supplying the program code, for example, a floppy disk, hard disk, optical disk, magneto-optical disk, CD-ROM, CD
-R, a magnetic tape, a nonvolatile memory card, a ROM, or the like can be used.

When the computer executes the readout program code, not only the functions of the above-described embodiment are realized, but also the OS (Operating System) running on the computer based on the instruction of the program code. ) May perform some or all of the actual processing, and the processing may realize the functions of the above-described embodiments.

Further, after the program code read from the storage medium is written in a memory provided in a function expansion board inserted into the computer or a function expansion unit connected to the computer, based on the instruction of the program code, It goes without saying that the CPU included in the function expansion board or the function expansion unit performs part or all of the actual processing, and the processing realizes the functions of the above-described embodiments.

When the present invention is applied to the above-mentioned storage medium, the storage medium stores the program code corresponding to the above-mentioned flow chart. Briefly, in the memory map example of FIG. Each module shown will be stored in the storage medium. That is, at least the "input processing module", the "expansion processing module",
The program code of each of the “prediction processing module”, the “notification processing module”, and the “print output processing module” may be stored in the storage medium.

[0053]

As described above, according to the present invention, when the print data input from the host is expanded into bitmap data and stored in the storage medium, it is predicted whether the capacity of the storage medium will run short. According to the prediction result, the message is bitmapped and overlayed on the bitmap data so that a message indicating that the overrun has occurred is output to the recording medium where the overrun is expected, or the message is overlaid on the host. Since the occurrence of the overrun and the information of the page of the recording medium in which the overrun occurs are transmitted together with the notification of the overrun occurrence,
There is an effect that it is possible to easily know from which print medium output page the overrun has occurred, from the print output result or from the host.

[0054]

[Brief description of drawings]

FIG. 1 is a block diagram illustrating a configuration of a printer system according to a representative embodiment of the present invention.

FIG. 2 is a side sectional view showing an internal structure of a printer device including a printer engine 107 that performs recording by adopting an electrophotographic method.

FIG. 3 is an external perspective view illustrating an outline of a configuration of an inkjet printer IJRA.

FIG. 4 is a block diagram showing a configuration of a printer engine interface (I / F) 16 when a laser beam printer is used as the printer engine 17.

FIG. 5 is a printer engine interface (I / F) 1
6 is a block diagram showing a configuration of a control circuit of the inkjet printer IJRA controlled by the control unit 6 of FIG.

FIG. 6 is a flowchart showing print control processing.

FIG. 7 is a diagram showing memory allocation of RAM 19;

FIG. 8 is a flowchart showing a print control process according to another embodiment.

FIG. 9 is a diagram showing a memory map.

[Explanation of symbols]

 1, 12 CPU 2, 19 RAM 3a, 13a Font ROM 3b, 13b Program ROM 3c, 13c Data ROM 3d, 13d Hard disk (HD) 4 CPU bus 7, 20 Memory interface (I / F) 11, 14 External memory 15 System bus 17 Printer Engine 22 NVRAM 1000 Controller 1500 Printer 1501 Operation Panel 3000 Host Computer

Claims (14)

[Claims] 1. Input means for inputting print data from a host; expansion means for expanding the print data input by the input means into bitmap data; storage means for storing the bitmap data; and storage means. Output means for printing out on a recording medium using the bitmap data stored in, prediction means for predicting whether or not the capacity shortage of the storage means is likely to occur, and occurrence of overrun according to the prediction result by the prediction means. The bitmap data is overlayed on the bitmap data so as to output a message indicating the occurrence of overrun to the recording medium, or the host is notified of the occurrence of the overrun and the overrun. By sending together with the information on the page of the recording medium where the run occurs, Printer apparatus characterized by comprising a notification means for notifying the occurrence of Baran. 2. The printer device according to claim 1, wherein the print data includes PDL data. 3. The printer device according to claim 2, further comprising an interpreter unit that interprets the PDL data. 4. The storage medium has a capacity equal to that of the recording medium 1.
2. The printer device according to claim 1, wherein the amount of bit map data corresponding to a page is smaller than that of the bit map data. 5. The printer device according to claim 1, wherein the output unit includes a printer engine that forms an image according to an electrophotographic system. 6. The printer device according to claim 1, wherein the output unit includes a printer engine that forms an image according to an inkjet method. 7. The printer device according to claim 1, further comprising a large-capacity auxiliary storage unit for storing the bitmap data. 8. According to the prediction result by the prediction means,
8. The printer device according to claim 7, further comprising moving means for moving the bitmap data stored in the storage means to the auxiliary storage means. 9. The printer device according to claim 8, wherein a storage area larger than the storage capacity of the storage means is secured in the auxiliary storage means during movement by the movement means. 10. Even if the moving means stores the bitmap data stored in the storage means in the storage area of the auxiliary storage means, when the bitmap expansion causes a shortage of the storage area, the overflow occurs. The printer apparatus according to claim 9, further comprising notification control means for controlling the notification means to notify the occurrence of a run. 11. The printer device according to claim 7, wherein the auxiliary storage unit is a hard disk. 12. The printer device according to claim 1, wherein the storage unit is a RAM. 13. A print control method for print output to a recording medium, comprising: an input step of inputting print data from a host; and a developing step of expanding the input print data into bitmap data and storing the bitmap data in a storage medium. A prediction step of predicting whether or not the capacity of the storage medium is likely to occur, and outputting a message indicating the occurrence of overrun to the recording medium in which the overrun is expected to occur according to the prediction result in the prediction step. The message is bit-mapped and overlayed on the bit-mapped data, or the message of the over-run is transmitted to the host together with the information of the page of the recording medium in which the over-run occurs and the information of the over-run is transmitted. A notification step of notifying occurrence, and a bitmap stored in the storage medium Printing control method according to an outputting step for printing out on the recording medium using the chromatography data. 14. A computer-readable memory in which a program code for executing print control processing at the time of print output to a recording medium is stored, the code executing an input step of inputting print data from a host, and the input print data. A code for executing a decompressing step of decompressing into a bitmap data and storing it in a storage medium, a code for performing a predicting step for predicting whether or not a capacity shortage of the storage medium is likely to occur, and a prediction result in the predicting step , The bitmap data is overlaid on the bitmap data so as to output a message indicating the occurrence of overrun to a recording medium in which the overrun is expected, or the overrun occurs in the host. And the information on the page of the recording medium in which the overrun occurs. And a code for executing an output step of printing out to the recording medium by using the bitmap data stored in the storage medium. A computer-readable memory characterized by the following.