ID Number: Q77091
2.00 2.00a 2.00b 2.00c
MS-DOS
Summary:
PROBLEM ID: PRLAN9109001
SYMPTOMS
When a Microsoft LAN Manager enhanced DOS workstation completes a
print job to a shared printer and attempts to access file server
resources, the workstation may fail.
Workstations using various electronic mail (e-mail) and database
applications will display various symptoms. The application will
attempt to retry the process that failed or it will terminate the
process. Symptoms vary, depending on the error handling routine
provided by the application. Several potential LAN Manager errors
will then be displayed by the workstation:
Network retrying will be indicated by workstation beeping.
Net815: Network name was deleted
Net810: Unexpected Network error
Net805: Network device no longer exists
Note: These symptoms have been observed using applications
including CCMail, Revelation, and Omnis5 Window Database
applications.
CAUSE
In some cases, the enhanced redirector will perform a previously
completed command instead of the command currently assigned. In the
example below, the last available workstation buffer was used to
successfully complete the printing process. At this point, the
buffer was made available. However, the buffer was not reallocated
properly. As a result, the previously associated command, a Spool
Byte Range SMB (server message block), was submitted again.
The command was incorrectly submitted rather than the currently
assigned SMB, which was intended to access the file server
following the Lock & Read SMB.
RESOLUTION
Modify LANMAN.INI located in the LANROOT directory on the DOS
workstation. Increase the value assigned to NumWkBuf. For example,
the default setting of 5 can be increased to 10. This will help to
prevent the redirector from reallocating the last available buffer
incorrectly.
STATUS
Microsoft has confirmed this to be a problem in LAN Manager version
2.0c. We are researching this problem and will post new information
here as it becomes available.
The DOS enhanced redirectors, NETWKSTA.*, will be modified to
correct this problem. These fixes will be included in LAN Manager
2.0c upgrade Patch 10, as well as LAN Manager version 2.1.
More Information:
Example
-------
A LAN Manager workstation accesses an application from a LAN Manager
file server. It successfully submits a job to a shared LAN Manager
print queue. After the print job is completed, the file server is
accessed. During the process of accessing the file server, a failure
occurs. As shown in packet 3 listed below, the workstation attempts to
perform a Spool Byte Range SMB command during the process of accessing
a data file. This is not a valid request and the server responds
appropriately.
Sample Sniffer Trace
--------------------
Destination Source Description
----------- ------ -----------
1) FileSVR Wksta SMB C F=1E52 Lock & Read 512 at 0
2) Wksta FileSVR SMB R Locked & Read
*3) FileSVR Wksta SMB C Spool Byte Range
4) Wksta FileSVR SMB R Invalid TID
Additional reference words: 2.00 2.00a 2.00b 2.00c 2.10