JPS61264459A - Data transfer system - Google Patents

Abstract

PURPOSE:To transfer continuously data blocks with high efficiency by adding a state qualifying status to the transfer of data and informing collectively the interruptions for report of reception to a CPU after the reception of the data block. CONSTITUTION:A CPU decides previously the number of bytes designated by a CCW and informs the number of bytes to the CPU by a setting command. At the same time, the CCW consisting of at least a read or write command, a command chain flag, the byte number, a data transfer area, etc. and the CCW consisting of a NOP command, a command chain, a program interruption flag, etc. are chained in plural pieces when a transmission/reception command is produced. An additional information area is set at the data transfer area of the CCW. The CPU counts the transfer bytes during the execution of a command. In case the end of a block is detected within the informed byte number, the transfer of data is carried out together with the additional information showing the valid display of end information, the transfer byte number, the details of errors, etc. Then the transfer of data is through with the input/output device end status and the channel device end status.

Description

[Detailed Description of the Invention] [Table of Contents] Overview Industrial Field of Application Conventional Technology Problems to be Solved by the Invention Means for Solving the Problems (Fig. 1) Working Examples (1) Structure of the Invention ( (Figures 2 to 5) (2) Operation of the invention (3) Second embodiment of the invention (Figures 6 and 7) Effects of the invention [Summary] Data exchange with the terminal device by commands from the central processing unit In a data communication system having a communication control device that controls transmission and reception, the central processing unit issues a read (write) command, a command chain flag, a CCW (A) having a data transfer area, a NOP command, and a command chain when issuing a transmission/reception command. The communication control device counts the number of data transfer bytes, and if the end of the data block is not detected within the number of bytes notified in advance, it changes the status ( SM) status, the data is continuously transferred, and additional information including the transfer byte length is written in the data area so that the central processing unit can read the transfer byte length for each ICCW (A).

[Industrial application field]

The present invention relates to a data transfer method, and particularly relates to a central processing unit (hereinafter referred to as CPU) in a data communication system and a communication control device (hereinafter referred to as ccp) connected via a channel device.
[Prior art] In general, the input/output operation of an input/output device is performed using an input/output start command from the CPU and a channel command word (hereinafter referred to as "CCW").
). This CCW is read by the channel. By the way, the format of CCW is shown in Figure 4 (a).
As shown in the figure, it is composed of a command section CMD, a flag section FLG, a byte count section BC1, a data address section DTA, etc.

The command part CMD is an instruction to be executed by the input/output device, and is decoded by the channel when CCW is read, and the input/output device is notified of commands other than the command to wake up the channel and the invalid command.

When an I/O device receives a command, it begins the I/O operation defined by the code.

The flag section FLG has the format shown in FIGS. 4-), and specifies execution of a channel program for a channel. The CD of this flag part FLG indicates the presence or absence of chain data (data chain), CC indicates the command chain, and SLi indicates suppression, so it is OK even if the instructed number of data bytes and the actual number of bytes do not match. thing,
5kip indicates that data reception is ignored, PCl indicates a program interrupt, and iDA indicates an indirect address.

The byte count section BC indicates the number of bytes indicating the size of the data area of the transfer destination, and the data address section DTA indicates the start address in the main memory of the data area to be transferred, which is used as the number of data bytes. is specified.

Now, due to the input/output start command from the CPU, the channel is
When the CW is read, the command of this CCW is notified to the input/output device, and the input/output device makes an executable response, a series of startup operations is completed, and data transfer will be performed thereafter.

When a data transfer request is received from an input/output device, the channel transfers the data to the area of the main memory specified by the data address section DTA. The channel subtracts the byte count each time to manage the number of bytes transferred. If the byte count section becomes zero during data transfer, the flag section FL
The CD of bit 8 of G is determined, and if this CD is ON, a new CCW stored in the main memory is read out following the currently executing CCW, and data transfer is continued. This is a data chain. This data chaining is performed by channels and is transparent to input/output devices.

If no data chain is specified (the CD is 0FF),
In order to terminate the currently executing CCW, a data transfer termination instruction is issued to the input/output device. The input/output device that receives the data transfer end instruction ends the command execution and reports it to the channel.

When the channel receives the end of the command from the input/output device, it uses the byte count value and the contents of the flag section FLG.
Decide to run the channel program as follows:

■ When the byte count is zero, bit 9 of the flag section FLG
If the CC is ON, a new CCW is executed because a command chain is instructed. Also, if the byte count section is not zero, the SL of bit 10 of the flag section FLG
When i is determined and it is ON, the command chain is executed in the same way as when the byte count is zero.The new CCW read in the command chain at this time differs depending on the status of the input/output device.If the status is the input/output device completed For example, if the channel device is terminated, it is read from address +8 of the current CCW, and if the status is input/output device terminated, channel device terminated, or status modification, it is read from address +16 of the current CCW.

■ If command chaining is not performed other than the above, the channel requests an input/output end interrupt to the CPU. When the input/output interrupt is accepted, the address location of the executed CCW+8 and the updated byte count contents and status are stored in a fixed area of the main storage device, and the input/output operation is ended.

The above is an overview of input/output operations.

[Problem that the invention seeks to solve]

In a data communication system, the CCP is positioned as an input/output device and controls data transmission and reception based on commands from the CPU, but it may continuously receive a plurality of data blocks of undefined length from a terminal device.

Methods for performing this receiving operation using the prior art described above include: first, issuing a READ command for each block; second, using data chaining; and third, using command chaining, etc. is possible.

However, in the first method, since the CPU requires an input/output start instruction for each block, there is a drawback that the processing capacity of the system is reduced due to startup and interrupt overheads.

In the second method, since the received data block has an undefined length, there is no guarantee that it will match the prepared byte count, and data chaining will be inhibited at the point of mismatch.

Furthermore, the third method has the disadvantage that there is no means to know the amount of data transferred for each block. In other words, in the command chain, the byte count of the last executed CCW is notified, but the byte count of the CCW executed in the middle cannot be known.

As mentioned above, the object of the present invention is to
The purpose of this invention is to provide a data transfer system using a chain, which could not be realized with the conventional technique, in order to improve the receiving operation which caused a decrease in performance in the case of continuous reception of blocks in the conventional technique.

[Means for solving problems]

In order to achieve the above object, in the data transfer method of the present invention, in a data communication system having a CCP that controls data transmission and reception with a terminal device based on instructions from the CPU, the CPU transmits the number of nodes specified by the CCW. A CCW (A) consisting of at least a read (or write) command, a command chain (CC) flag, the number of bytes, a data transfer area, etc., is determined in advance and notified to the CCP by a set command, and when issuing a transmit/receive command, Notupu (N
OP%NO0operation) command, chain of command (
As shown in FIG. 1, a plurality of CCWs (B) consisting of CC), program interrupt (Pct) flags, etc. are connected in a chain. An additional information area is defined in the data transfer area of the CCW (A)', and data length, etc., for example, is written in this area. Then, the CCP counts the number of transferred bytes during command execution, and if the end of the block is detected within the notified number of bytes (Figure 1 data B)
performs data transfer with additional information indicating completion information valid indication, number of transferred bytes, error details, etc., and ends with input/output device end and channel device end status. In addition, if the end of the block is not detected within the notified number of bytes (data A in Figure 1), the completion information is displayed as invalid,
Data transfer is performed with additional information such as the number of bytes to be transferred, and is configured to be terminated once with input/output device termination, channel device termination, and state modification (Status Modifier, SM) status.

[Effect]

This makes it possible to continue the command and perform data transfer, and furthermore, the number of data transfer bytes by each CCW can be determined from the additional information.

〔Example〕

(1) Structure of the Invention An embodiment of the present invention will be described based on FIGS. 2 to 5.

Fig. 2 is a block diagram of an embodiment of the present invention, Fig. 3 is a block diagram of the CCW when issuing a reception command in the present invention, and Fig. 4 is a block diagram of the CCW.
A detailed diagram of FIG. 5 is an explanatory diagram of additional information.

In FIG. 2, 50 is a CPU, and 51 is a main memory in which, for example, CCW is stored and a CPU data area is provided. 52.53 is the channel device, 60 is the CC
P, 70, 71 are terminal devices.

The CCP 60 includes a control unit 61 that comprehensively controls the CCP;
It is composed of a transfer control section 62 that controls transfer with the channel device, a control area 63 that stores various control information, and line connection sections 64 and 65 that control lines such as modems. The control area 63 also includes a received byte counter 81, a status storage area 82, storage areas 83 and 84 for holding the number of bytes and the number of buffers notified from the CPU, and the like.

The CCW has a configuration as shown in FIG. 4, and its format is similar to the conventional one. The command section CMD contains the command to be executed.The flag section FLG indicates the chain data flag CD indicating the data chain, the chain command flag indicating the command chain CC1, and the length of the data that was transferred. Chain length display suppression flag SLi (Su
ppress Length Indication
n), skip (Sk i p) flag 5kip, program control interrupt flag PCt (ProgramC
(interruption),
Indirect data address flag IDA (Indirect
Data Address), etc.

In FIG. 3, 10 is C that constitutes the READ command.
CW, 11 is a CCV constituting the NOP command, and 12 is a data area designated by the CCWIO. 20 again
,21.22-・NO,,N1,N2 are as above 10.11
．． 12 shows the CCW and data area of a command similar to No. 12. And MO is Ttc (
Transfer in c
hannel) command or the CCW that constitutes the NOP command.

CCWIO120, NO flag part has a command chain (CC
) and chain length inhibition (SLi) are specified.

The byte count section (B C'') is the buffer size of the data area, and as described above, the number of bytes notified to the CCP in advance before issuing the receive command is written therein.

The command chain (C
G), chain length inhibition (SLi) and program interrupt (Pc
t) is specified. PCt is a function that generates a program interrupt to the CPU when the CCW is executed, and is executed by a channel.

Further, the data area is structured as shown in FIG. 5, and additional information of, for example, 8 bytes in length is added to the beginning of the data area. This additional information includes ID information 120, information type information 121, completion information 122, data length information 123, error detail code information 124, and the like. ID information 1
20 indicates the type of data; for example, the IDs that identify the terminals (stations) connected to the line are 1.2-2 in the order of the stations.
...is given. At this time, in the case of a line, roll
Indicated by (X). The information type information 121 is “00” (
X): I frame reception, "10": XID frame reception, X20 and kit trace data (receiving system)
When it is "72", the statistical information (type 2) is "73".
" indicates statistical information (type 3), etc.

The completion information 122 consists of first completion information and second completion information of 1 byte each. If the first completion information is roll (X), it indicates a normal completion; otherwise, it indicates an error, and the second completion information is [. ...IJ (B) indicates the final data of one section, and "... ...0" (
B) indicates that the data to be transferred by the next READ command is continuous.

The data length information 123 indicates the length of the l frame stored in this buffer, for example, when receiving an I frame,
In the case of reception notification, byte 8 indicates the length of the transferred l frame; in the case of trace data (transmission, reception), byte 8
Indicates the stored data length.

The error detail code information 124 includes the contents of the A field of the frame that caused the error, the contents of the C field of the frame that caused the error, and the like.

(2) Operation of the present invention ■ Referring to FIG. 2, a case will be described in which the CPU 50 receives data (READ) from the terminal device 70.

The CPU 50 notifies the CCP 60 of the buffer size (number of bytes) and maximum data block length (number of buffers) using a set command issued prior to data communication.

The CCP stores the notified number of bytes 83 and the number of buffers 84 in the control area 63, internally reserves two or more data areas for the notified number of bytes, and waits for a READ command. The CPU 50 prepares the CCW shown in FIG. 3 and starts the CCP 60. When the CCP 60 is activated by the CCWIO READ command, data is subsequently received from the line, and at this time, the received byte counter 81 is set to the value of n bytes of additional information.

Here, the additional information is the number of bytes predetermined between the CPU 50 and the CCP 60, and in this embodiment is composed of 8 bytes.

That is, an area having a size obtained by subtracting 8 bytes from the number of bytes (data area) specified by the CCW will be used as the received data area (number of bytes).

(2) Upon receiving data from the line, the control unit 61 of the CCP 60 performs processing according to transmission control and stores the received data in an internal data area. In this case, the received byte counter 8
A value of 1 is used as a storage address in the data area, and the received byte counter 81 is updated by +1. Thereafter, processing is repeated until the end of the data block is detected, but when updating the received byte counter, a comparison is always made with the notified number of bytes, 83.

(2) When the end of the data block is detected within the notified number of bytes, 83, the control unit 61 creates additional information shown in FIG. 5 and stores it at the beginning of the data area. Then, the input/output device end (DE), channel device end (CE), and status are stored in the status area 82, and a data transfer request is made to the transfer control unit 62. After the data transfer is completed, the contents of the status area 82 are notified to the channel 52 (data B in FIG. 1).

■ Also, if the end of the data block is not detected within the notified number of bytes 83, that is, the number of bytes 83 notified before the end of the data block is detected and the value of the received byte counter 81 being updated matches. In this case, the control unit 61 also creates additional information and status, but in this case, the maximum data block length (84 buffers) notified from the CPU 50 is checked. That is, if data garbled in the end character of a data block occurs, the end of the block cannot be detected, so invalid data will also be continuously received.

Therefore, the maximum data block length, that is, the number of buffers used in one block (84) is checked, and if it is within the range, additional information is created with the completion information 122 and error detail code 124 set to zero, and the beginning of the data area is Store in.

And input/output device end (DE) in status area 82
, channel device end (CE), status modification (SM), and status are stored, and a data transfer request is made to the transfer control unit 62. After the data transfer is completed, the contents of the status area 82 are notified to the channel 52 (data A in FIG. 1).

Data received during data transfer to the channel 52 or status notification is stored in two or more separate data areas of the CCP 60 in the same manner as described above, and reception operations are performed sequentially.

If the end character of the data block is garbled, that is, if the maximum block length notified from the CPU 50 is exceeded, the error details are set in the additional information, and the input/output device end (DE) is written in the status area. , channel device end CCE> , and the reception of the data block is forcibly terminated. Needless to say, new data blocks are subsequently received in the same manner as described above.

■ On the other hand, after data transfer, the channel device 52
When the status is received from CCWlo, the next CCW is executed from the command chain of CCWlo (CC is ON), but the next CCW to be executed as shown in FIG. 3 differs depending on the status from the CCP 60.

a. The status from CCP60 is input/output device completed (D
E), in the case of channel equipment termination (CE), the executed C
CCWII after CWIO (e.g. executed ccwto
address) is executed.

b. The status from CCP60 is input/output device completed (D
B), channel equipment termination (CE), state modification (S, M)
In the case of , the next CCW2O (
For example, the executed CCW+16 address) is executed.

By the way, since CCWll in a above is a NOP command, the CCP 60 performs an immediate operation (the CCP does nothing and immediately terminates with input/output device end (DE) and channel device end (CE)), and the channel device 5
2 will execute the next command CCW2O by the command chain (CC'') of CCWII, but the CC
Since the program interrupt PCi is designated for WII, the program interrupt PCi for the CPU 50 is also performed. Thereafter, while executing the CCW2O, the channel device 52 executes the next CCW of the current CCW or the next CCW in the same manner as described above, depending on the status of the CCP 60.

(2) On the other hand, the CPU 50 can know the execution status of chained CCWIOs by a program interrupt from the channel device 52. The CPU 50 learns the data area from the executed CCWIO through this program interrupt, reads its additional information, and assembles a data block based on this information. At this time, the end of the second completion information of the additional information is “
0'' indicates that the data is included in the following CCW, and a value other than rOJ indicates that the data has been completed within the area.

In the case of FIG. 1, data transfer is first performed in which data A1 to A3 are made into one block, and then data transfer is performed in which data B is made into one block.

The CCP 60 receives data A (A-A t +A2 +A
3), first, data A1 is sequentially stored at an address increased by 8, which is the additional information of the internally reserved data area. And when data A1 is satisfied, C
The CP 60 stores additional information as shown in FIG. 5 at the beginning of this data area.

In this case, since the end of the data block has not been detected, the input/output device end (DE), channel device end (CB), and status modification (SM) statuses are stored in the status area. After the data is transferred to the MS 51, a status notification is sent to the channel device 52. The channel device 52 reads and executes the next CCW2O from the previously executed CCWIO due to this status, particularly the presence of state modification.

Due to this execution, even when the CCP 60 processes data A2 and creates a status, the block end of the data is not detected, so the CCP 60 similarly processes the input/output device end (DE), channel device end (CE), and status modification. (S
M) Output the status. This allows channel device 5
2 skips CCW21 and executes ccwao.

Data A3 is processed by this execution of CCW3O, and when the end of the block is detected, the count value of the received byte counter 81 is smaller than the notified value of the number of bytes, so the status is changed to "End of input/output device". (
DE), the channel equipment end (CE) status is output.

Since the command chain CC is ON in the flag section FLG of CCW3O, the channel device 52 is now SM
Because there is no CCW3O, read CCW31 after CCW3O,
Run this. Since this CCW31 is NOP and the flag FLC and PCi of the section are ON, the CPU5
A program interrupt for 0 is made and one block transfer of data A is reported to the CPU 50. By reading the additional information at the beginning of each data area, the CPU 50 can know the number of bytes received in the executed ccwio, CCW2O, and CCW3O.

In addition, the flag part of CCW31 also has a command chain CC.
is ON, the channel device 52 selects the next CCW of the CCW 31.
Read CW4O and execute it.

At this time, the amount of data B is within the storage range of one data area, so when the transfer of data B is completed, the input/output device is terminated (
DE), the channel equipment end (CE) status is output. Channel device 52 therefore reads CCW41 following CCW4O, thereby causing program interrupt PCi
will be output to the CPU 50.

(3) Second embodiment of the invention A second embodiment of the present invention will be described with reference to FIGS. 6 and 7.

In this second embodiment, when processing a plurality of data blocks, even if the transfer of one data block is completed, the CPU
This allows continuous processing without interrupt processing.

FIG. 6 shows the main part configuration of a CCP 60 in a second embodiment of the present invention, and FIG. 7 is an explanatory diagram of the operation of the second embodiment.

As shown in FIG. 6, the CCP 60 includes a control section 61, a transfer control section 62, a control area 63, and a line connection section 64.65, and the control area 63 includes a received byte counter 81,
Status storage area 82, notified byte count storage area 83
, In addition to the notified buffer number storage area 84 (each corresponding to FIG. 2), there is a continuous notification block number storage area 8.
5 and a block reception counter 86.

The number of consecutive notification blocks indicates the number of data blocks to be notified in one program interrupt, so prior to data communication, the CPU 50 (Figure 2) determines the buffer size (number of bytes), maximum data block length, (buffer The control unit 61 detects the end of the data block and creates the input/output device end (DE) and channel device end (CB) status, and then detects the end of the data block. (Block reception counter 86) replaces this with a state modification (SM) status added thereto.

Therefore, as shown in FIG. 7, for example, data A (A
1 +A2 +A3) and data B, the CPU 50 determines the buffer size to be used and the maximum data block length (number of buffers) prior to data communication, as in the previous case. The number of consecutive notification blocks (2 in the example of FIG. 7) is also notified to the CCP 60. As a result, the ccp 60 stores the number of consecutive notification blocks, 2, in the storage area 85, and also sets the number of consecutive notification blocks, 2, in the block reception counter 86. Then, the same processing as in the above case is performed, but when the end of the data block is detected when transferring data A3, the control unit 61 sends the additional information shown in FIG. 5 and the input/output device end (
After creating the statuses ``DE'' and ``CE'', the block reception counter 86 is decremented by 1. As a result, the block reception counter 86 becomes 1, but since it is not zero, the control unit 61 replaces it with a value to which a status modification (SM) status is added.

As a result, as shown in FIG. 7, the next CCW 40 following the CCW 30 is executed.

Then, when the CCW 40 is executed and the end of the data block B is detected, the control unit 61 starts the block reception counter 8.
6 is subtracted by 1, so this block reception counter 8
6 becomes zero.

As a result, the control unit 61 recognizes that the transfer processing of the predetermined continuous transfer data block has ended, so no state modification (SM) is added, and (continuous notification is sent to the block reception counter 86 for reception of the next block). The contents of block number 85 will be reset)) The input/output device end (DE) and channel device end (CE) status will be output.

As a result, the CCW 41 is then read out, a program interrupt Pct is performed, and the completion of data transfer is reported to the CPU 50.

〔Effect of the invention〕

According to the present invention, even when a data block larger than one data area is received, it is possible to continuously receive the data blocks by adding a status modification status, and the reception report can also be sent. interrupts for the CPU after receiving the data block.
Therefore, the frequency of program interrupts to notify the CPU can be significantly reduced compared to the conventional case where a program interrupt is used to report to the CPU every time one data area is received. can. Moreover, it is also possible to continuously transfer a plurality of data blocks without interrupting the CPU.

Furthermore, since additional information is written in the data area, it is possible to know the number of data transfers for each execution of each CCW.

[Brief explanation of drawings]

Fig. 1 is a detailed explanatory diagram of the present invention, Fig. 2 is a block diagram of an embodiment of the present invention, Fig. 3 is a block diagram of the CCW at the time of issuing a reception command, and Fig. 4 is a block diagram of the CCW.
An example of CW, FIG. 5 is a data area explanatory diagram, FIG. 6 is a CCCP in a second embodiment of the present invention, and FIG. 7 is an operation explanatory diagram of the second embodiment of the present invention. 50--1-・CPU 51・-・Main memory 52
．． 53--Channel device 60--CCP 61--Control section 62--Transfer control section 63--Control area 64.65--Line connection section 70.71--Terminal device 81--Received byte counter 82 -- Status storage area 83 -- Byte number storage area 84 -- Buffer number storage area

Claims (2)

[Claims] (1) In a data communication system equipped with a communication control device that controls data transmission and reception with terminal devices based on commands from the central processing unit, the central processing unit specifies the channel command word of the command issued for data transmission and reception. The number of bytes to be transmitted is determined in advance and notified to the communication control device, and when issuing a transmission/reception command, a channel command word that includes at least a read (or write) command, a command chain flag, the predetermined number of bytes, and a data transfer area is issued. (A) and a channel command word (B) comprising a NOP command, a command chain, and a program interrupt flag are provided in a chain, and the data transfer area of the channel command word (A) has a certain number of channels. In addition to determining the additional information transfer area and issuing the command, the communication control device counts the number of transferred bytes while the command is being executed, and if the end of the block is detected within the notified number of bytes, the completion information is displayed as valid. Performs data transfer with additional information indicating the number of transferred bytes and error details, etc., and is configured to terminate with input/output device end and channel device end status,
If the end of the block is not detected within the notified number of bytes, the data is transferred with additional information such as invalid completion information and the number of transferred bytes, and the input/output device is temporarily terminated, the channel device is terminated, A data transfer method characterized in that the data transfer method is configured to terminate with a state modification status, and data transfer is continued by the next command issued in a chain. (2) Provide means for changing the input/output device termination and channel device termination status of the communication control device to the input/output device termination, channel device termination, and status modification status, and the number of consecutive notification blocks notified from the central processing unit is 2. The data transfer system according to claim 1, wherein the change is made accordingly.