IE69537B1 - Control of peripheral devices in a data processing system - Google Patents

Description

Control of Peripheral Devices in a Data Processing System The invention relates to the control of peripheral devices in a data processing system, and more particularly to the peripheral devices to which data is outputted.

In data processing systems which handle a very large 5 amount of data, the recording of data in peripheral devices such as printing on hard copies or recording in tape drives is an extremely important aspect. It is these operations which ensure that if a hardware or indeed a software fault occurs that there is a record of existing data and that the system may be back up and running relatively quickly. It is also important on a daily basis in disseminating information for users. Where the data processing system is large and complex, and where there are users spread over many geographical locations, the task of outputting data to peripheral devices becomes quite complex. If it were only a matter of, say, printing data at a single central printer or group of printers, there would be few technical problems. However, where it is vital that information is distributed very quickly to users spread over different geographical locations in order to work efficiently in an organisation, then the technical steps in transmitting the data and having it printed in a timely manner and also in outputting the data to tape drives for backup purposes becomes quite complex.

European Patent Specification No. 139,759 BI describes a system for connecting and controlling external devices. In this method, information is applied at an input to the main apparatus indicative of external equipment to be connected. However, if the data processing system is very complex this approach would not necessarily be the best.

The invention is directed towards providing further control of peripheral devices which record data in an efficient manner with the requirement for the minimum of user instructions so that peripheral device control is coordinated.

According to the invention, there is provided a peripheral device control method carried out by a peripheral controller connected to a processor which is also connected to a storage device, to a back-up tape drive and to a cluster cable, the cluster cable also being connected to a plurality of other processors, each connected to an associated storage device and a back-up tape drive, the data processing system further comprising a printer server connected to the cluster cable and having ports connected to printers, either local or remote and also a terminal server connected directly to the cluster cable and having ports connected to terminals for user inputting of instructions comprising the steps ofsmonitoring a print instruction received from a terminal and determining the terminal server port at which it was received; automatically determining a printer port associated with the terminal port at which the printing instruction is received; monitoring size of the print file associated with the printing instruction; monitoring a priority indicator for the print instruction; automatically generating revised print instructions according to the monitored parameters and transmitting the revised instructions together with the print file to a spooler; controlling storage of the print instructions and file in the spooler according to a plurality of generic queues, each associated with a group of printers; a printer controller associated with a group of printers communicating with the spooler and with the peripheral controller to maintain an execution queue for each printer, depending on the status of the printer and of the print instructions in the spooler; the peripheral controller carrying out a process of monitoring active contents of each of the storage devices connected to the processors of a cluster and carrying out sequential passes of comparing the number of active memory locations in each storage device with available space on backup tapes which may be driven by the tape drive; the peripheral controller carrying out automatic passes until all of the contents in each storage device have been flagged for writing to a single tape; the peripheral controller directing transmission of the data to the various tapes according to the flagged configuration; and the peripheral controller storing the configuration used in non-volatile memory for reference at the next back-up batch process.

The invention will be more clearly understood from the following description of some preferred embodiments thereof, given by way of example only with reference to the accompanying drawings, in which:5 Fig. 1 shows a data processing system incorporating a peripheral controller of the invention; and Fig. 2 shows diagrammatically the manner in which printers are controlled.

A data processing system 1 is shown in Fig. 1 which comprises a cluster of processors 3, 4 and 5 connected to a cluster cable 2. The processors 3, 4 and 5 are connected to storage devices 6, 7 and 8. A back-up tape drive 9 is connected to each processor 3, 4, and 5. A printer server 10 which has a number of ports which are connected to various types of printers including an asynchronous laser printer and a fast dot matrix printer is connected directly to the cluster cable 2. A terminal server 12 having ports 13 for various printers and terminals is also connected directly to the cluster cable 2.

For control of the peripheral devices including the printers which are connected to the servers 10 and 12 and the back-up tape drives 9, the system 1 includes a peripheral controller 14 forming part of one of the processes, namely, the processor 3.

Zn operation, the processors 3, 4 and 5 carry out transaction data processing involving a very large amount of data. This involves frequent set cycles to the storage devices. In order to ensure data integrity and that appropriate use is made of the available data, the manner in which this data is outputted to peripheral devices including the back-up tape drives 9 and the various printers is extremely important. This is particularly so because the processing system involves a cluster of machines, with both local and remote printers, and even the local printers being at different locations within a large building. Other criteria involved in the outputting of data to printers is that there are many different printers and there are different requirements.

Where a document is to be printed, an instruction is 10 received on one of the terminals connected to the terminal server 12. The peripheral controller 12 monitors the printing instruction and firstly detects the actual port 13' at which the instruction is received. According to stored look-up tables, the controller 14 automatically determines a printing port 11 or 13 associated with that user. The controller then transmits the printing instructions, together with the printing file (which has been retrieved from a storage device 6, 7 or 8 via the cluster cable 2) to a spooler (not shown) connected to the processor 3. While doing this, the peripheral controller 14 monitors the size of the file and inserts a disk parameter value according to the size within the instructions which are transmitted to the spooler. Another parameter which is included with the instructions in the spooler is a priority number for the file, which value is extracted automatically from the printing instructions inputted by the user.

An important aspect of operation of the peripheral controller 14 is that it not only assigns the desired printer port 11 or 13 for a particular print job and inserts all of the necessary parameters and instructions, but it also controls the order in which printing occurs. This involves setting up a number of generic queues 20 shown in Fig. 2. Each generic queue 20 has a group of printers associated with it, this group of printers being determined according to the port number. Different generic c queues may share printers. For example, for printing on instructions from a remote user, the generic queue would be that associated with the remote data processing system and this generic queue will be associated with all of the printers in that system. In addition to the generic queues, there is additionally an execution queue 21 associated with each printer. The execution queues 21 are controlled by a local printer controller which communicates with the peripheral controller 14 via the ports 11 and 13. The printer controller continuously monitors the status of each printer. It may, for example, write a print file directly from the generic queue in a spooler to a printer, or it may take its place in an execution queue 21 depending on the priority indicator which has been included in the instructions, and the size of the file.. Smaller files are printed first, provided a higher priority has not been given to the larger files.

For control of transmission of data from the storage devices 6, 7 and 8 to the tape drive 9, the peripheral controller 14 also acts in an automatic manner to ensure that this is done as efficiently as possible, with data integrity. In this embodiment, the total capacity of the storage devices, 6, 7 and 8 is 8.3 GB, while the total capacity of the back-up tapes is only 6 GB. However, there is never full utilisation of the storage devices 6, and 8 and thus mapping of the contents of the storage devices to the tapes in the tape drive 9 are important.

In a first pass the peripheral controller 14 determines ( how much of the storage device 6 is active and subtracts this front the capacity of the tape drive and calculates the remaining space. It then determines the active locations of the second storage device 7 and compares this to the remaining capacity on the tape. In this first task, the controller 14 flags the remaining space on the tape for the storage device 7. The first pass is continued sequentially until the active portion of each of the storage devices 6, 7 and 8 have been flagged for storage in one or more of the tapes. This may require a second pass if it has not been possible to store the active contents of a particular storage device all on a single tape. Once these passes have been completed, the controller 14 then automatically controls writing of the data from the storage devices to the back-up tapes on the tape drive 9. In addition, the controller also automatically stores the configuration for the back-up and at the next back-up batch process it will automatically check if this configuration applies again. This is particularly important in reducing the processing time for the making of a back-up where the active contents of the various storage devices change relatively little between the two back-up time periods. It also ensures that all data is automatically backed up each time a log is generated.

It has been found that the operation of the peripheral controller is extremely important in ensuring the smooth functioning of a host processing system in disseminating information exactly where it is required and in a timely manner. This is extremely important where there is a large amount of data and the main purpose of the data processing system is providing information when and where it is required and ensuring that records are made of ail data at regular time periods. An example of the type of data processing which the invention particularly assists is payroll processing for a large organisation.

The invention is not Ί ted to the embodiments hereinbefore described but may be varied in construction an detail.

Claims (2)

1. A peripheral device control method carried out by a peripheral controller of a data processing system, the peripheral controller being connected to a processor which is also connected to a storage device, to a backup tape drive and to a cluster cable, the cluster cable also being connected to a plurality of other processors, each connected to an associated storage device, and a back-up tape drive, the data processing system further comprising a printer server connected to the cluster cable and having ports connected to printers, either local or remote and also a terminal server connected directly to the cluster cable and having ports connected to terminals for user inputting of instructions, the method comprising the steps of:monitoring a print instruction received from a terminal via a server and the cluster cable and determining the terminal server port at which it was received; automatically determining a printer port of the printer server associated with the terminal port at which the printing instruction is received; monitoring size of the print file associated with the printing instruction; monitoring a priority indicator for the print instruction; automatically generating revised print instructions according to the monitored parameters and transmitting the revised instructions together with the print file to a spooler via the cluster - 9 cable and the printer server; controlling storage of the print instructions and file in the spooler according to a plurality of generic queues, each associated with a group of printers; a printer controller connected to a group of printers and to the spooler communicating with the spooler and with the peripheral controller to maintain an execution queue for each printer, depending on the status of the printer and of the print instructions in the spooler; f the peripheral controller carrying out a process of monitoring active contents of each of the storage devices connected to the processors of the data processing system and carrying out sequential passes of comparing the number of active memory locations in each storage device with available space on back-up tapes which may be driven by the tape drive; the peripheral controller carrying out automatic passes until all of the contents in each storage device have been flagged for writing to a single tape; the peripheral controller directing transmission of the data from the storage devices via the cluster cable to the various tapes according to the flagged configuration; and the peripheral controller storing the configuration used in non-volatile memory for reference at the next back-up batch process. 10

2. A method substantially as hereinbefore described with reference to and as illustrated in the accompanying drawings.