OPERATIONAL CONSIDERATIONS FOR VIANET 3.06 The following operational considerations are provided for the users of ViaNet and should be read closely before actually using ViaNet. 1. The timing considerations of using the LAN for data transmission may preclude redirecting a COM port to a remote node. 2. The DOS PRINT command does not function under the net. The functions performed by this command are provided by the ViaNet print spooler (VIAPRINT and VIASPOOL). The spooler allows the printing of files on a remote node in a fashion similar to the DOS PRINT command. NOTE: The ViaNet print redirection facility (REDIRPRT and SETPRT) routes output bound for a print device directly to the VIASPOOL print queue. 3. Application programs which bypass the facilities of MS-DOS by branching directly to ROM addresses or non-documented system addresses may not function properly. In addition, application programs which modify reserved DOS data areas or use undocumented interrupts may not function properly. 4. Protection for the root directory of disk devices is not supported. 5. Programs which depend on native MS-DOS timing characteristics may not function properly. 6. The MS-DOS TREE, DISKCOPY, FORMAT, and CHKSDK are not supported on remote resources. 7. The error recovery actions taken for 'Floppy Door OPEN' conditions on a remote node may hang both the local and remote nodes. 8. MS-DOS pipes, when used with internal DOS commands that do not open or close the FCBs or HANDLEs used for system input or system output, give unpredictable results and, in some cases, do not function at all. In particular, executing command.com with the input or output redirected to a file will not work as expected. For example: A:> command < comfile where comfile contains commands such as dir, type file, exit, etc., behaves as if redirection had not been specified. 9. The CTTY DOS command is not supported. 10. Background processes must check the INNET and INDOS ViaNet flags prior to doing interrupt 21 system calls in order to function properly. All local disk files must be referenced from the background using local path names only. Local files referred to by a full network path name by a background process will cause the request to time out. 11. Programs which use interrupts 25 and 26 (direct read and write system calls) are not supported across the network. 12. Record locking for non-disk devices is not supported. File locking for non-disk devices is not supported except for device PRN when using MACASGN PRN Z:\nodename\PRN [/S] as documented. 13. Since some FCB I/O is converted to HANDLE I/O, FCB I/O may be slower than I/O done with Handles. The number of handles available at a node can be defined by the user in NETCNF.SYS. The handles are broken down into the following groups: 0-19 reserved for applications running at the node for files residing on the node. 20-29 reserved for applications running at the node for files accessed with FCBs. 30-xxx reserved for applications that open remote files. Where xxx is the value specified by FILES = xxx in NETCNF.SYS. A remote file is one that is opened at another node by an application running at the node, or a file that is opened at the node by an application running at another node. 14. Some DOS internal commands completely utilize the compute cycles of the local machine in a fashion which prevents ViaNet from servicing requests from other nodes. For example: o CTRL S to stop the screen display, will cause the node to stop sending and receiving network requests until CTRL Q (or whatever start character is being used) is entered. o COPY CON filename has the same effect as CTRL S and will prevent network communication for that node until EOF (CTRL Z) is entered. In these situations, the remote node sees the message 'Drive Z: not ready'. The remote user may recover from this by replying 'R' to indicate a retry is desired. 15. Redirection of devices other than PRN to files is not supported. When MACASGNing prn to a file, the user must include the complete path, i.e. MACASGN PRN C:\TEST.FIL. 16. Local devices should not be accessed using a network path. When local devices are accessed using a network path there is a performance degradation. In addition, if the node is receiving a great deal of network activity (i.e. the node is a server), the frequency of 'Drive Z: not Ready' messages increases if local devices are being accessed using a network path. 17. The way some editors (i.e. EDLIN) create backup (.BAK) files, it appears that files marked read only (RO) can be updated. What is actually happening is that the original file, which is marked read only, is renamed to filename.BAK. When the edit session is over, a new file is created with the old filename and extension. Although the .BAK file is marked RO, the new file is not. 18. The ViaNet print redirection facility (REDIRPRT and SETPRT) has been tested for the following applications: WordStar WordStar 2000 Multiplan 1.0 Lotus 1-2-3 v. 1.0 Multimate Deskmate DBase III Plus v. 1.0 Smart Scriptsit Wordperfect 19. Print redirection (REDIRPRT) does not redirect Ctrl-P or Prtsc. 20. If both VIASPOOL and REDIRPRT are loaded at the same node, VIASPOOL must be loaded first. 21. If REDIRPRT and "Sidekick" are loaded at the same node, REDIRPRT must be loaded first. If there is a conflict with the key combination used by ViaNet print redirection (CTRL-ALT-PRTSC) and an application, the application must change since REDIRPRT cannot. 22. REDIRPRT does not work with MACASGNed strings. For example: MACASGN string LPT1 If a print to 'string' is issued REDIRPRT will not recognize 'string' as a valid printer and the output will not be redirected. 23. It is possible to create an unreliable network environment by adjusting the parameters to unreasonable values in the NETCNF.SYS file located in the NETSYS directory. For example: If timeout = 1 and tort = 200 the network will continuously timeout. For more information about the NETCNF.SYS file please refer to the Network Administator's Guide. 24. When setting up the network configuration file (NETCNF.SYS), it is necessary to set the THROWOUT parameter to a lower value than the TIMEOUT parameter. For example: TIMEOUT = 1000 THROWOUT= 950 25. When using the ViaNet print spooler (VIASPOOL) on a node that is running an application that scans the keyboard for input, DOS interupt 16 instead of DOS int 21, noticable printer delays are encountered. VIASPOOL relys on DOS idle time to print and when an application scans for input it does not allow idle time. 26. Several VIASPOOL options, if incorrectly implemented, will cause the spooler node to act unpredictably. For example: If VIASPOOL is installed with the "L" switch to specify a list device driver and no device driver is specified or if the "N" switch is specified for timer events on a computer that does not require special timer considerations. The "L" switch should be used with the following machines only: Zenith Z100 Tandy 2000 Wang PC 27. It should be noted, that when running VIASPOOL the printer that VIASPOOL is using must remain online or the spooling node may appear to hang. 28. ViaNet has limitations that might be different than DOS. The following descriptions give the general situations you may want to avoid to prevent unpredictable results: A. The DOS makedirectory (MD) command with a path of eighty or more characters. B. When using FCB's (File Control Blocks), ViaNet translates FCBs to handles. ViaNet reserves 10 handles for this purpose. If an application opens 10 FCBs and a request for another FCB is received, ViaNet closes the first used FCB. C. When using floppy disk drives locally, ViaNet does not change to the root directory of the destination floppy when the floppy disk is changed and the default drive is different than the floppy. D. When using COPY CON to create a file the normal CONTROL C break out command will not abort the COPY CON process. A CONTROL Z is the only way out. 29. The ViaNet MACASGN command allows the operator to reassign local devices. When making such macasgns caution must be exercised to prevent data destruction of those devices. For example: SYS1 has a local drive a. TEST1 has a drive c available to the network. SYS1 macasgns a: z:\test1\c. SYS1 performs a format on local drive a. error is generated and format fails. With DOS 3.1 or higher a check for network drives will catch the above condition, however with prior releases of DOS this could format the remote drive as if it were local. 30. NETDRVR.SYS is a standard DOS Device Driver which allocates drives for network use. NETDRVR.SYS appears in the CONFIG.SYS file which resides in the ROOT directory of the boot drive. The nature of NETDRVR.SYS requires that it be the last device listed in the CONFIG.SYS file. If NETDRVR.SYS does not appear in the CONFIG.SYS file and is not loaded by the boot process before attempting to load the NETWORK, the attempted load of VIANET.EXE will cause the system to hang.