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Contents
1. SUMMARY OF THE INVENTION The present invention is directed to an improved method in the form of software and firmware for supporting a scan peripheral over the network whereby an improved server apparatus can handle network contention situations and can provide a connectionless protocol for control data and a connection oriented protocol for scan data Additionally the present invention provides an improved server that can recover from a client tying up but not using a scanner for an extended period 10 15 20 25 30 35 40 45 50 55 60 65 2 In one aspect of the present invention the server waits for a client to attempt to open a connection with the peripheral When the client sends a peripheral connection request via a data packet to the server the server accepts the connection The server determines an availability of the peripheral and locks the peripheral so that it cannot be used by other clients Thereafter the server opens a connection with the peripheral if it is available and notifies the client of the peripheral availability The server then waits for predeter mined data from the client which when received results in the client having control of the peripheral for at least a first predetermined time period and when received sends the data to the client The server closes the connection with the client upon completion of sending the data to the client DESCRIPTION OF THE DRAWINGS FIG2. 1 is an overview of the network system FIGS 2A 2C are flow charts of the network server embodying the present invention and FIG 3 is a flow chart of a state machine located in the server embodying the present invention TABLE OF ACRONYMS This patent utilizes several acronyms The following table is provided to aid the reader in determining the meaning of the several acronyms ASCII American standard code for information inter change CPU central processing unit ID identification THV independent hardware vendor P internet protocol MFPDTF multifunction peripheral data transfer format MIB management information base PC personal computer SAP service advertising protocol SCL scanner control language SLP service location protocol SNMPeasimple network management protocol SPX sequenced packet exchange TCP transmission control protocol DETAILED DESCRIPTION Broadly stated the present invention is directed to an improved method in the form of software and firmware for supporting a scan peripheral over the network More particularly the present invention is able to provide an improved server apparatus that can handle network conten tion situations and can provide a connectionless protocol for control data and a connection oriented protocol for scan data Additionally the present invention provides an improved server that can recover from a client tying up but not using a scanner for an extended period Turnin
3. Pore epee SERVER CLEANUP SEE FIG 2C dee 83 START SCAN 6e 2 d 2 c 2 SCAN DATA TRANSFER 84 DISCARD SCAN DATA SRVRCLEANUP SEE FIG 2C U S Patent Apr 24 2001 Sheet 4 of 5 US 6 223 223 B1 LEGEND CLIENT OPERATIONS SERVER CLEANUP SERVER OPERATIONS peewee ww wwe eb ew eee ee CLOSE NETWORK CONNECTION peewee wee ee eb ee eee ee CLEAR NAME AND ADDR OBJS ewer ee ee ee He be ee ee ee CLOSE SCAN CHANNEL ENSURE SCAN READY SET STATE TO IDLE ee FIG 2C U S Patent Apr 24 2001 Sheet 5 of 5 US 6 223 223 B1 LEGEND EVENT OR STATE ACTION AVAILABLE SEND NETWORK DISCONNECT RECEIVE NEGATIVE RESPONSE TO OPEN CHANNEL REQUEST RECEIVE NETWORK CONNECTION SEND OPEN CHANNEL REQUEST TO PERIPHERAL RECEIVE NEGATIVE RESPONSE TO OPEN CHANNEL PERIPHERAL POWERED OFF RECEIVE DISCONNECTED NETWORK DISCONNECT RECEIVE POSITIVE 35 PERIPHERAL RESPONSE TO OPEN POWERED OFF CHANNEL REQUEST OPEN WAIT DISCONNECTED CLOSE 34 RECEIVE POSITIVE Eo RESPONSE TO OPEN CHANNEL RESPONSE 27h IDLE TIMEOUT RECEIVE CLOSE NETWORK NETWORK CONNECTION DISCONNECT PERIPHERAL POWERED OFF DISCONNECTED SEND CLOSE CHANNEL REQUEST TO PERIPHERAL CLOSE WAIT FIG 3
4. is open block 664 Since the scan channel is not open at this stage in the method the server 10 merely sets the scan status SNMP MIB object to the integer zero to indicate that the scanner is IDLE block 66g While the server 10 performs the cleanup operation the client 12 checks the data packet and displays an error message stating that the server 10 could not communicate with the scanner and prompts the user to determine if the user wishes to select another server 10 block 67 If the user so indicates the client invokes a process to select another server 10 The preferred process is the discovery method mentioned above block 20 If the scan channel opens successfully however the server 10 returns for example a 00 status string to the client 12 on the network connection indicating that the scanner is AVAILABLE block 68 The client 12 receives the status code from the server 10 determines that the US 6 223 223 B1 5 scanner is AVAILABLE and sets the owner name SNMP MIB object on the server 10 block 70 The client 12 provides a name that can be used by other clients 12 to inform users who are currently scanning The preferred embodiment is to set an SNMP MIB object with the name of the user or client computer At this point in time the client 12 has effective ownership of the scanner and can send scan control commands using in band or out of band transmis sion channels and initiate one or more scans Thus the
5. the server s scan port the server 10 auto matically accepts connection with the client 12 hence establishing a network connection between the client 12 and the server 10 through an exchange of data packets block 22 After the client 12 has connected to the server 10 the server 10 checks the state of an internal state machine to determine whether or not the scanner is available block 24 The server 10 contains the state machine shown in the flow chart of FIG 3 which represents various internal states that key off external events blocks 27a through 27j to represent a current state of the scanner For example the internal state of the state machine changes from the scanner AVAILABLE state block 28 to an OPEN WAIT state block 30 when the server 10 attempts to open a connection with the scanner block 29 Likewise the internal state changes from an OPEN WAIT state block 30 to an ACTIVE state block 32 when the scan channel opens block 33 An OPEN WAIT CLOSE state block 34 occurs when a network connection is terminated block 35 while waiting for the peripheral 16 to respond to an open scan channel request A CLOSE WAIT state block 36 occurs when the server 10 sends a close scan channel request packet to the peripheral 16 block 37 Returning to FIG 2 if the internal state of the server 10 is in any other state than available the server 10 sends a scanner busy status for example 01 to the client 12 block 38 A
6. 36 US 6 223 223 B1 1 NETWORK SCANNER CONTENTION HANDLING METHOD The present invention generally relates to software and firmware i e software embedded on a system and more particularly to software and firmware for supporting scan ners over a network Scan peripheral vendors typically provide custom soft ware that takes advantage of features of the product however the custom software is typically written to com municate only with a single device over a local interface such as a SCSI bus or a parallel port While the local interface design is simple the design fails to address issues that occur when the peripheral is attached to a network Thus attached scanners cannot utilize the custom software and associated features A problem exists with scanners and other peripherals attached to the network since multiple users can access the peripherals Scanners for example typically require some setup before starting an actual scan If no controls are in place contention between clients could occur where one client sends commands to set the scanner resolution page size and other options in preparation for starting a scan at the same time another client is issuing similar commands to the same scanner One client s commands could overwrite the commands of another client Similarly one client can send commands to reset the scanner while another client s scan is in progress and effectively abort the other client s scan job Anot
7. United States Patent US006223223B1 12 10 Patent No US 6 223 223 B1 Kumpf et al 45 Date of Patent Apr 24 2001 54 NETWORK SCANNER CONTENTION 5 933 580 8 1999 Uda etal a 710 19 HANDLING METHOD 5 946 458 8 1999 Austin et al wee 358 1 15 5 968 138 10 1999 Clough see 710 8 75 Inventors David A Kumpf Rocklin Glenn R 6 101 555 8 2000 Goshey etal 709 301 Garcia Grass Valley Dean L Scoville cited by examiner Auburn all of CA US David L Smith Pittsburgh PA US Primary Examiner Mehmet B Geckil 73 Assignee Hewlett Packard Company Palo Alto 67 ABSTRACT CA US A network peripheral support method including a client with T 2 ome a general purpose software capability and a server connected Notice Subject to any pne the ee ps to the peripheral The server of the present invention waits P c 1 Pn 0 d adjusted Unger for a client to attempt to open a connection with the ud b by 0 days peripheral The client sends a peripheral connection request via a data packet to the server and the server accepts the 21 Appl No 09 163 496 connection The server determines an availability of the 22 Filed Sep 30 1998 peripheral and locks the peripheral so that it cannot be used TY by other clients Thereafter the server opens a connection 51 Int Cl ise ea G06F 15 16 with the peripheral if it is available and notifies the client 52 US CL su awa qa al
8. at 10 15 20 25 30 35 40 45 50 55 60 65 4 the scanner is not BUSY then the server starts a server idle timer block 56 The server idle timer acts so that one client 12 cannot tie up the scanner for more than a threshold time period without data being sent or received between the client 12 and the scanner before the server idle timer expires A threshold time period of five minutes was found to be desirable but can be changed to suit the clients 12 needs Since the scanner is not BUSY the server 10 locks the scanner ie prevents other clients 12 from using the scanner by setting the scan status SNMP MIB object to the integer one to indicate that the scanner is BUSY block 58 The server 10 also sets a scan owner address SNMP MIB object to the client s network 14 address and the scan owner name SNMP MIB object to an empty string block 60 Thus the client software can set the scan owner name SNMP MIB object so that other clients 12 can determine which client 12 has control of the scanner as utilized above Thereafter the server 10 attempts to establish communi cation with the scanner by opening a logical scan channel block 62 and determines whether or not the scan channel connection was successful block 64 The server 10 opens a communication channel to the peripheral for scanning The preferred embodiment is a logical channel opened when needed and multiplexed with other logical channels u
9. ck 106 As shown in FIG 2C the server 10 closes the network con nection with the client 12 block 66b Additionally the server 10 sets the owner address and owner name SNMP MIB objects to the empty string block 66c The server 10 also closes the scan channel block 66e and invokes the scanner ready state operation as incorporated by reference above block 66 Furthermore the server 10 sets the scan status SNMP object to the integer zero to indicate that the scanner is IDLE block 66g From the foregoing description it should be understood that an improved server 10 has been shown and described which has many desirable attributes and advantages The present invention is able to provide an improved server 10 apparatus that can handle network 14 contention situations Additionally the present invention provides an improved server 10 which can recover to keep a client 12 from tying up a scanner for too long Further the present invention provides meaningful error messages to the client 12 While various embodiments of the present invention have been shown and described it should be understood that other modifications substitutions and alternatives are apparent to one of ordinary skill in the art Such modifications substi tutions and alternatives can be made without departing from the spirit and scope of the invention which should be determined from the appended claims Various features of the invention are set forth in the appe
10. client prompts the user to insert a document into the scanner block 72 An alternate possibility is to skip this step if the client 12 can determine that a document is already inserted in the scanner This is not preferred however because the client 12 may scan a document left in the scanner by a previous user The client 12 begins a client idle timer set to expire for a time slightly less for example ten seconds less than the server idle timer block 74 The client idle timer avoids a race condition where the server idle timer expires a new user begins to scan a document but the current client 12 detects a change in scanner status and tries to start a scan intended for the new user After beginning the client idle timer the client 12 peri odically polls a scan button and paper insertion status on the peripheral 16 block 76 In a preferred embodiment the client checks for the document by polling an SNMP MIB object on the peripheral In the preferred embodiment the client detects the presence of the document to be scanned by checking for a user action on the client computer such as clicking a button or checking for a user action on the peripheral such as pushing a SCAN button after loading the document or checking a sensor in the peripheral that changes state when a document is loaded It should be understood that some peripherals may not provide a button or sensor and that the client 12 software must be fashioned accordingly If
11. e 709 227 709 203 of the peripheral availability The server then waits for 58 Field of Search 709 227 203 predetermined data from the client which when received 709 223 224 201 217 218 219 710 8 results in the client having control of the peripheral for at 19 least a first predetermined time period and when received sends the data to the client The server closes the connection 56 References Cited with the client upon completion of sending the data to the client U S PATENT DOCUMENTS 5 913 088 6 1999 Moghadam et al 396 311 15 Claims 5 Drawing Sheets SERVER JET DIRECT EX U S Patent Apr 24 2001 Sheet 1 of 5 US 6 223 223 B1 U S Patent Apr 24 2001 Sheet 2 of 5 US 6 223 223 B1 LEGEND START SCAN SERVER CLIENT OPERATIONS OPERATIONS 18 GET SERVER ADDRESS 20 OPEN NET CONN TO SERVER 22 77 SCAN NO AVAIL ee ee ee SEND BUSY 01 TO CLIENT a ee START IDLE TIMER SET STATE TO BUSY 46 SET CLNT ADDR CLEAR NAME OBJ 52 ATTEMPT OPEN SCAN CHANNEL SEND ERR 02 TOCLIENT 6 SRVRCLEANUP SEEFIG2C 66 SEND OK 00 TO CLIENT YES SELECT NEW SERVER 67 FIG 2A U S Patent Apr 24 2001 Sheet 3 of 5 US 6 223 223 B1 PROMPT FOR DOCUMENT START IDLE TIMER WAIT FOR DOCUMENT LEGEND CLIENT SERVER OPERATIONS OPERATIONS 74 CLOSE 82 CONNECTION 8 A
12. e operation is complete In the event the document is ready to scan block 80 i e the user presses the scan button on the scanner clicks the continue button on the client or inserts the document into a self feed scanner The client 12 begins the scan operation 10 15 20 25 30 35 40 45 50 55 60 65 6 on the peripheral 16 block 92 The client issues peripheral specific commands to commence scanning the document The server 10 transmits client data typically scan commands to the peripheral 16 and transmits peripheral data typically scan image data to the client 12 block 94 The server idle timer is reset every time the server receives data from either the client or the peripheral In normal operation the data transfer continues until the client 12 receives the complete scan job the client 12 detects the end of the scan job and closes the network connection blocks 95 96 The client 12 processes the image as requested by the user for example saving it to a file block 100 If the network connection closes unexpectedly the client 12 discards the scan data block 102 and displays an appropriate error message block 104 Several error condi tions can arise during the scan job including loss of network communication loss of peripheral communication and the server idle timer expiring After the scan job ends either normally or unexpectedly the server 10 performs a cleanup operation blo
13. g now to the drawings and particularly FIG 1 a server 10 waits for a client 12 on a network 14 to establish a connection with at least one peripheral 16 For purposes of the present invention the peripheral 16 is a scanner The server 10 of the present invention waits for the client 12 by listening for a network 14 scan connection on a scan port utilizing for example a transmission control protocol internet protocol TCP IP or sequenced packet exchange SPX protocol While the server 10 referred to is used as part of a Hewlett Packard JETDIRECT EX box package it US 6 223 223 B1 3 is contemplated that the server 10 can be part of a card that connects via a bus interface to the peripheral 16 or as part of an internal central processing unit CPIJ of the peripheral 16 The JETDIRECT EX box is shown and described in a Hewlett Packard user manual part no 5967 2290 and is incorporated by reference herein Referring to FIG 2 a user prompts the client 12 to send a scan connection request to the server 10 scan port block 18 The client discovers a new network scan server address or retrieves a previously stored address block 20 A pre ferred discovery technique is disclosed in a commonly owned co pending application to Kumpf et al filed concur rently herewith and entitled Networked Peripheral Server Discovery Method That application is incorporated by reference herein After the client 12 sends the scan connec tion request to
14. her problem exists in network scanning when a scan connection is indefinitely held open by one client While the connection remains open other clients are unable to access the scanner Thus there is a need for a software that has a timeout and a recovery to keep any one client from tying up the scanner for too long Another problem exists with network scanning since the peripheral is usually centrally located and not visible to the client device status is typically not readily available to a network client With locally attached peripherals peripheral status can usually be determined either visibly due to the proximity of the peripheral or by viewing error messages reported by the local operating system or local software Thus device error messages reported to an application running on one client s personal computer PC are not propagated to other clients PCs on the network Accordingly it is a primary object of the present inven tion to provide an improved server apparatus that can handle contention on the network Another object of the present invention is to provide such an improved apparatus which can recover to keep a client from tying up a scanner for too long on the network Yet another object of the present invention is to provide meaningful error messages to the client on the network Other objects and advantages will become apparent upon reading the following detailed description in conjunction with the attached drawings
15. ll scanner server statuses used herein are strings of two ASCII characters 01 in ASCII is transferred as an octet with the value 48 in decimal followed by an octet with the value 49 in decimal Other methods of encoding the status are apparent to one skilled in the art Importantly as the client 12 receives the result code from the server 10 a result of BUSY or 01 prompts the client 12 to obtain a current owner name from the server 10 block 44 and display a BUSY message using the name block 46 Preferably the client 12 obtains the name by sending an SNMP query of a owner name management information base MIB object however the server 10 could send the owner name MIB object over the network connection before the network connection is closed By using the owner name MIB object the client s message can include the name of the current user This enables the user attempting to open the connection locate the person currently using the scanner It is recognized that in some situations this may be a security issue so the client software can provide an option not to supply a owner name MIB object The server s 10 acquisition of the current owner name to set the owner name MIB object is discussed below On the server s 10 side after sending the BUSY message the server 10 closes the network connection block 52 As the client 12 attempts to open a connection with the server 10 if the internal state of the server 10 represents th
16. n claim 3 wherein said predeter mined time period is approximately 5 minutes 5 A method as defined in claim 1 wherein the server includes an associated state machine the server determining availability of the peripheral by checking its associated state machine 6 A method as defined in claim 1 wherein said client attempts to establish a connection with the peripheral by sending a TCP IP or SPX request to the server 7 A method as defined in claim 1 wherein the server sends an unavailability status indication to the client in the event the peripheral is unavailable the client then displays an error signal and the server closes the server peripheral connection 8 A method as defined in claim 3 wherein said server client connection is closed by the client in the event prede termined peripheral operating conditions do not occur within a second predetermined time period 9 A method as defined in claim 8 wherein said second predetermined time period is less than said first predeter mined time period 10 A method as defined in claim 8 wherein said prede termined peripheral operating conditions comprise one of detecting a scan operation being commenced and paper being inserted into the peripheral 11 Amethod as defined in claim 1 wherein said peripheral availability determining step includes determining whether the peripheral has a busy status or an idle status 12 A method as defined in claim 1 wherein said prede termined data com
17. nded claims What is claimed is 1 A method of supporting at least one peripheral in a network including at least one client with a general purpose software capability and a server connected to the peripheral the method comprising steps of the server waiting for a client to attempt to open a connection with the peripheral the client sending a peripheral connection request to the server the server accepting connection with the client via exchange of data packets the server determining availability of the peripheral and locking the peripheral so that it cannot be used by other clients the server opening a connection with the peripheral if it is available and notifying the client of the peripheral availability the server waiting for predetermined data from the client which when received results in the client having con trol of the peripheral for at least a first predetermined time period US 6 223 223 B1 7 the server waiting for data from the peripheral and when received sends the data to the client the server closing the connection with the client upon completion of sending the data to the client 2 A method as defined in claim 1 wherein said peripheral is adapted to perform a scan operation 3 A method as defined in claim 1 wherein said server client connection is closed in the event no data is sent between the peripheral and the client within a second predetermined time period 4 A method as defined i
18. prises the client identification 13 Amethod of supporting a scan peripheral on a network having at least one client with a general purpose software capability and a server connected to the peripheral the method comprising steps of the server waiting for a client to attempt to open a connection with the peripheral the client discovering the address of the server the client sending a scan peripheral connection request to the server the server accepting connection with the client 10 15 20 25 30 35 40 45 8 the server determining the busy or idle status of the peripheral and locking the peripheral when it has an idle status so that it cannot be used by other clients the server opening a connection with the peripheral if it is idle and notifying the client of the peripheral idle status the server waiting for predetermined data from the client which when received results in the client having con trol of the peripheral for at least a first predetermined time period during which the client can initiate a scan operation by the peripheral the server waiting for data from the peripheral and when received sends the data to the client the server closing the connection with the client upon completion of sending the data to the client 14 A method as defined in claim 13 wherein the server sets a server idle timer upon opening a connection with the client and with the peripheral the server monitoring t
19. ransfer of data between the peripheral and the client and resetting said server idle time upon transfer of data between the same and closing the connection with the peripheral in the event transfer of data does not occur within a second predeter mined time period 15 A server for supporting the operation of a scan peripheral connected in a network having at least one client with a general purpose software capability the server being connected to the scan peripheral via the network the server comprising means for responding to a client generated scan request and accepting a connection with the client means for accepting a connection from the client means for determining the busy or idle status of the peripheral and locking the peripheral when it has an idle status so that it cannot be used by other clients and for opening a connection with the peripheral if it is idle and notifying the client of the peripheral idle status means for providing control of the peripheral for at least a first predetermined time period during which the client can initiate a scan operation by the peripheral responsive to the server receiving predetermined data from the client the server being adapted to wait for data from the periph eral and send the data to the client when received the server closing the connection with the client upon completion of sending the data to the client
20. sed for other purposes such as printing However if the peripheral does not support multiple channels across the communica tion link with the server scanning is still possible but other services will not be able to communicate at the same time Also the scan channel can be opened once at initialization and kept open between scan jobs This is not preferred however because it ties up peripheral and server resources when there is no scan job in progress If the scan channel open request fails then the server 10 returns for example 45 an ERROR 02 status string to the client 12 on the network connection as part of a data packet on the network connection to indicate that the scanner is not available block 65 For example the 02 status occurs if a cable connecting the server 10 to the scanner has detached or the peripheral 16 does not support scanning After the client 12 sends the data packet containing the status string the server 10 invokes a cleanup subroutine as shown in FIG 2C The cleanup subroutine involves deter mining whether a network connection is open block 66a If the network connection is open the server 10 closes the network connection with the client 12 by sending a packet to close the network connection block 66b Additionally the server 10 clears the owner name and address SNMP MIB objects by setting the MIB objects to the empty string block 66c Next the server 10 determines whether the scan channel
21. the client idle timer expires the client closes the net work connection block 82 On the server 10 side the server 10 discovers that the client 12 has closed the network connection and invokes the cleanup subroutine shown in FIG 2C block 83 Thus the server 10 sets the owner address and owner name SNMP MIB objects to the empty string blocks 66c Since the scan channel is open the server 10 closes the scan channel block 66e and ensures that the scanner is in a ready state i e performs any operations on the peripheral 16 necessary to ensure the peripheral 16 is in a known state and ready for the next scan job block 66 The exact operations are peripheral specific and may not be required for some peripherals 16 A preferred error recovery technique is disclosed in a commonly owned co pending application to Scoville et al filed concurrently herewith and entitled Network Scan Server Ready State Recovery Method That application is incorporated by ref erence herein Additionally the server 10 sets the scan status SNMP object to the integer zero to indicate that the scanner is IDLE block 66g Thereafter the client 12 displays an error message which notifies the user that the timer has expired and prompts the user to decide whether the user would like to try to scan again block 84 If the user desires to try another scan the client 12 begins the operation by opening a network con nection to the server block 22 Otherwise th
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