DCOM95 1.3
Release Notes
Last Modified: March 14, 1998

DCOM95 provides Distributed COM support for Microsoft® Windows® 95.
The DCOM wire protocol transparently provides support for reliable, 
secure, and efficient communication between Component Object 
Model (COM) components such as ActiveX® controls, scripts, and 
Java applets residing on different machines in a LAN, a WAN, or on 
the Internet. With DCOM, your application can be distributed across 
locations that make the most sense to your customer and to the 
application.

For more in-depth information, see the DCOM Technical overview 
available on the Microsoft COM home page, 
http://www.microsoft.com/com/.

Contents
========
I.   New Features since DCOM95 1.2
II.  Bug Fixes since DCOM95 1.2
III. Known Issues
IV.  Differences from DCOM on Windows NT
V.   Redistribution
VI.  Support & Resources
VII. File List

I. New Features since DCOM95 1.2
--------------------------------

Support for VB6.0 Data Types

Visual Basic® 6.0 allows Visual Basic variants to contain user-
defined data structures. DCOM95 now supports remoting of these 
variants.

II. Bug Fixes since DCOM95 1.2
------------------------------

This section describes bugs fixed in DCOM95 1.3 that affected
applications running on Windows 95 with DCOM95 1.2 installed.

File Monikers Support Additional Path Syntax

File monikers can now be created out of arguments of the form 
<startdir><relativepath>, such as "C:\bug\bug\..\..\foo.jpg." In 
DCOM95 1.1, only relative paths (e.g., "..\..\foo.jpg") or absolute 
paths (e.g., "C:\foo.jpg") were permitted.

General Protection Fault When Oleaut32.dll Unloaded

In previous versions of DCOM95, a general protection fault occurred 
when Oleaut32.dll was unloaded before a call to CoUninitialize. This 
would most often occur when a VB application created a control 
statically linked to Oleaut32.dll, and then freed the control prior
to calling CoUninitialize. This no longer causes a general 
protection fault in the latest release of DCOM95.

Visual Basic Type Marshaling and Unmarshaling

The marshalling and unmarshaling of certain Visual Basic data 
types has been fixed. Array parameters with a size greater than 64K 
are now allowed. Structures defined using aliases to the type are 
now marshaled and unmarshaled correctly.

Atoms Being Deleted Too Many Times in OleUninitialize

This bug appeared in applications that call OleInitialize and 
OleUninitialize multiple times. During initialization, OLE adds many 
atoms for DDE RPC. If the atoms have already been added by 
another thread, they are not added again. However, during 
uninitialization, atoms were always deleted, and the handles were 
not nullified. Therefore, the next time OleInitialize was called, the 
old handles would still exist, even though the atoms were already 
deleted, and OLE would not add them again. This led to all OLE 
atoms being invalid after multiple calls to OleInitialize and 
OleUninitialize. This problem has been fixed in this release of 
DCOM95. 

ADO Servers Shut Down Properly

Active Data Objects (ADOs) use pointer monikers to start a server 
process. Previous versions of DCOM95 contained a bug involving 
pointer moniker reference counting, whereby pointer monikers were 
created with an initial reference count of 1, rather than 0. 
Therefore, the reference count of the pointer moniker would never 
get to zero, and the pointer moniker would never be freed. As a 
result, ADO servers were never shut down, even after the last 
pointer to them had been released. This has been fixed in this 
release of DCOM95.

CoCreateInstance Works with Own DNS Name

In previous versions of DCOM95, calling CoCreateInstance with the 
fully qualified name of the local machine did not work. This has been fixed in 
the current version of DCOM95, and CoCreateInstance now correctly 
creates and instance on the local machine.

Slow Commit On Root Storage With Very Large Compound File

In previous versions of DCOM95, the commit time on a root storage 
opened in STGM_TRANSACTED mode became very slow as the compound 
file became very large (e.g. 400M). The internal page table 
limits have been increased, and this is no longer a problem.

Exporting Objects From a Recreated MTA

In previous versions of DCOM95, a server could not export an 
object from a Multi-Threaded Apartment (MTA) if this was not the 
first time the MTA had been created in the process. This has been 
fixed. Now, if a server creates an MTA, destroys it, and 
subsequently recreates the MTA, objects will be able to be 
exported from the MTA.

Multiple Instances Of Visual Basic 4 EXEs

In DCOM95 v1.1, if you started multiple instances of the same 
Visual Basic 4 executable, then shut them down in any order but 
LIFO (Last-In First-Out), the last exe would hang. This was also 
true of E-Forms in Microsoft Exchange. This has been fixed in 
the latest release of DCOM95. You may now shut down Visual 
Basic 4 exes in any order.

Extended Characters in Visual Basic File Names

If you named a Visual Basic module or class using extended 
characters for a given language, that file might not open on 
machines configured for a different locale. This has been fixed.

Heap Memory Leak When Using IDataObject/IAdviseSink

There was a memory leak when using Uniform Data Transfer between 
a data object on a local server that implements the IDataObject 
interface and a client that implements IAdviseSink. When the 
client used the STA model, every call would leak 32 bytes. This 
problemmanifest itself as the server taking more and more time 
to execute. The leak has been fixed.

III. Known Issues
-----------------

Corel WordPerfect Suite 7: Installation Causes Invalid Page Fault

If you install Corel WordPerfect Suite 7 on a Windows 95 system 
running DCOM95, you may get an invalid page fault in PfOd70.pfc 
during installation. If this error appears, just close the error 
message dialog box. Setup should continue successfully.
 
Microsoft Access95: Database Replication Does Not Work

If you try to replicate an Access database using Microsoft Access 
95 on machines with DCOM95 installed, you may get the following 
error message: 

Microsoft Access cannot complete this operation because it 
can't find or initialize the dynamic-link library Msjtrclr. 

This is a problem in Microsoft Access 95. You may work around this 
issue by writing a program which uses the Access object model 
rather than the replica tool, or by using the briefcase for replication. 
Microsoft Access 97 is not affected by this issue. 

WordPerfect 

If you have a WordPerfect document containing an embedded 
Corel spreadsheet and the spreadsheet contains another 
embedded object (for example, a bitmap), you may get a warning 
dialog saying you’ve lost the network connection when you close the 
innermost object. There may be four or five such warnings. All 
these warnings are benign. Just close them and continue.

Multiple-threaded apartment (MTA) clients that use BSTR 
conversion routines may block DDE messages

Automation BSTR conversion routines (for example, BstrFromR4) 
create hidden windows to facilitate the type conversion. These 
windows do not service the Windows message queue. If such a 
window is created from within an MTA client, DDE messages may 
be blocked. The client thread has no obligation to service the 
message queue under the MTA programming model. If it does not, 
this top-level window causes global broadcast messages to block.

There are two ways to work around this situation. Either call the 
BSTR conversion routines from within a single-threaded apartment 
(STA) client, or make the client’s MTA thread behave like an 
STA thread. (An STA thread must service the message queue.) If 
the thread is blocking on a win32 handle, it must call the 
MsgWaitForMultipleObjects function to simultaneously dispatch 
Windows messages. 

DLL path names longer than 127 characters cause error

If you register a DLL with a path name of 128 characters or longer,
the registration will succeed, but CoCreateInstance or CoGetClassObject
will return an error (REGDB_E_CLASSNOTREG) when accessing an object
supported by this DLL.

IV. Differences from DCOM on Windows NT
---------------------------------------

Security Capabilities of DCOM95

The core functionality and application programming interface (API) 
for DCOM95 are identical in both Windows 95 and Windows NT 
4.0. However, certain capabilities related to security are different 
because of the different security infrastructures of the operating 
systems. Using the default security settings of the system is 
recommended; it is also necessary to enable "user-level" security 
on file-system shares. (See below.) 

The following services, which can be used to override default 
security, are available: 
*	CoInitializeSecurity 
*	CoQueryAuthenticationService 
*	CoQueryProxyBlanket 
*	CoSetProxyBlanket 
*	CoQueryClientBlanket 
*	IClientSecurity Interface 
*	IServerSecurity Interface 

However, certain capabilities that are part of DCOM for Windows 
NT will not be available on Windows 95 because of differences 
in the security infrastructure on Windows 95.

In particular, the lack of security functions in the Win32 API, such
as the ability to create access control lists (ACLs), and the 
AccessCheck function, as well as the lack of a security context 
associated with thread and process tokens, should be taken into 
account. Windows 95 does not natively support these functions or 
constructs. Because of this, DCOM95 will not support impersonation
(specifically, the CoImpersonateClient and CoRevertToSelf helper 
functions over the IServerSecurity interface), which is based on 
thread- and process-token security in Windows NT 4.0. Impersonation 
is commonly used to automatically control access to restrictable 
system resources such as the file system, other processes, and the 
network. These resources are not restrictable on Windows 95. 

DCOM95 does, however, offer programmers various helper objects 
to provide ACL and access-check functionality, which can be used 
to explicitly control access by remote clients to both system and 
user-defined resources or data. These helper objects are provided 
by the system object CLSID_DCOMAccessControl, which implements the 
IAccessControl interface.

IAccessControl should be used to manage security permissions 
programmatically wherever portability between Windows 95 and 
Windows NT is a concern. The CLSID_DCOMAccessControl object 
is available in all releases of DCOM95 and in Windows NT 4.0 
SP2 or later. For details about IAccessControl, see the Platform 
SDK documentation.

Launch and Access Security 

Controlling who can launch server-class code is not supported in 
DCOM95, because launching servers is not supported. 
Servers/classes must already be running in order for remote clients 
to connect to them and make use of their services. 

DCOM95 does support the ability to connect to already running 
classes/servers. Access security is supported via the 
\APPID\{.}\AccessPermissions registry key and adjusted via the 
DCOMCNFG tool or during installation or setup of the server code. 
Unauthenticated users will be able to use servers if you configure 
the class to support unauthenticated connections (through static 
configuration tools or dynamically via the CoInitializeSecurity 
function). You can also build arbitrary ACLs to define which users 
and groups can access specific services. 

Authentication Levels 

DCOM95 clients can make DCOM calls using any authentication 
level. DCOM95 servers or clients receiving callbacks can accept 
only DCOM calls using RPC_C_AUTHN_LEVEL_NONE or 
RPC_C_AUTHN_LEVEL_CONNECT authentication levels.

Transports

DCOM95 supports only TCP connectivity. If you do not have the 
TCP/IP protocol installed, DCOM95 will not be able to support 
cross-machine COM. 

Registry Settings 

The following registry keys found under 
HKEY_LOCAL_MACHINE\Software\Microsoft\OLE are established 
by DCOM95: 

EnableDCOM (default value = "Y"). Enables DCOM on this machine. 
When set to "N", the machine is prevented from connecting to or 
activating objects on remote machines, and remote machines are 
unable to connect to objects on the local machine. Setting this value 
to "Y" enables either connectivity as a client to remote objects 
(when EnableRemoteConnect='N', as explained below), or full 
client/server connectivity (when EnableRemoteConnect='Y', as 
explained below). 

EnableRemoteConnect (default value = "N"). Enables COM servers 
to support remote clients. When this value is set to "Y", references 
to interfaces on local objects can be passed to remote clients, and 
remote clients are allowed to connect to running objects. When this 
value is set to "N", this machine is allowed to connect to remote 
objects but cannot act as a server: the machine is prevented from 
connecting to running objects. 

In addition, the following registry key is found under 
HKEY_CLASSES_ROOT\CLSID: 

{bdc67890-4fc0-11d0-a805-00aa006d2ea4}\InstalledVersion. 
Contains the version number of DCOM95 in the format "a,b,c,d". 
This value can be used by Internet Component Download to 
determine whether DCOM95 is installed. This value is added to the 
registry during setup and should not be modified. 

Using Windows 95 as a remote server host

Windows 95 can be a remote server host, with the following 
caveats:
*	There is no launch capability. The server process must be 
	already running for a client to connect to it.
*	If secure connections are needed, the server (and in the case
	of callbacks, the client) must have user-level access control
	with the name of a security provider set. 
*	The registry value "EnableRemoteConnect" must be set to "Y".

DCOM95 has been tested most extensively using the Windows NT 
Domain security provider. You may encounter problems using other 
security providers.

To establish user-level access control, you must have Filesec.vxd 
installed. This file is generally installed on Windows 95 machines 
when you install file and print sharing.

To enable user-level access control, open the Network dialog box in 
Control Panel, click the Access Control tab, check the box marked 
User-level Access Control, and enter the name of your security 
domain. This may affect the way you currently share directories on 
the network from your computer; see the online documentation for 
details. If you do not have an Access Control tab in your network 
configuration control panel, you need to install a network client 
service. Click the Network clients, setting up entry in the online 
help index for information on installing a network client.

V. Redistribution
-----------------

For information about redistributing DCOM95, please review the
redistribution guidelines contained in the end-user license
agreement (license.txt).

If you elect to redistribute DCOM95, you should include the files
DCOM95.EXE and optionally DCM95CFG.EXE on your distribution media.
You should run these self-extracting executables from your setup
program. These executables will install the correct files only if
a more recent version is not already installed. They write the
correct registry entries required by DCOM95. They do not install
anything on Windows NT.

By default, DCOM95.EXE and DCM95CFG.EXE display a EULA and other
prompts to the user. DCOM95.EXE prompts the user to reboot the
system on completion. If you run either executable from your setup
program, you may elect to run the self-extracting executables in
"silent" mode. You must prompt the user to reboot the system when
your setup program exits if DCOM95 has been installed.

To run either DCOM95.EXE or DCM95CFG.EXE in silent mode, use the command line:
   [exe-name] /r:n /q:a

VI. Support & Resources
-----------------------

Paid Support

DCOM95 application development is supported by Microsoft 
Technical Support. You can ask questions through your Premier 
Level support contract. You can also ask questions through your 
Priority Level contract or purchase individual Priority Support 
incidents (essentially a one-time fee for one question). If you would 
like to understand more about Microsoft's paid support options, you 
can call Microsoft Support Sales at (800) 936-3500 from 6:00 a.m. 
to 6:00 p.m. Pacific time, Monday through Friday, excluding 
holidays. Please note that technical support is not available through 
this number. Microsoft Technical Support Information is also 
available on the World Wide Web at 
	http://www.microsoft.com/support/. 

Free Support

Newsgroups are a great place for free peer support. As time and 
resources allow, Microsoft developers, program managers, support 
engineers, and test engineers visit the site to collect feedback and 
answer questions or correct misperceptions. There is no guarantee 
that you will receive a response from Microsoft to any newsgroup 
posting. 

The following newsgroups can be used to ask questions about 
DCOM95: 
*	comp.os.ms-windows.programmer.ole 
*	microsoft.public.win32.programmer.ole

The DCOM mailing list is another good form of free peer support. 
An advantage to being on a mailing list is that this is where 
Microsoft will make early announcements of information on a given 
topic. Again, it is peer support, and Microsoft staff will often lurk 
there, but are not guaranteed to respond to any postings. 

To learn more about the DCOM mailing list, please review our 
Mailing List page, 
	http://www.microsoft.com/sitebuilder/resource/mail.asp.

Providing Feedback 

Please send any comments or bug reports to the DCOM mailing list. 

Resources

You can find additional information about DCOM on the COM Home 
Page at http://www.microsoft.com/com/.

VII. File List
--------------------

This table lists the version numbers of files distributed with 
DCOM95.

asycfilt.dll	 2.40.4275.1
comcat.dll	 5.0.1601.1
compobj.dll	 2.30.200.1
dcom2w98.dll	 2.10.35.35
dllhost.exe	 4.71.3328.0
iprop.dll	 4.0.1381.6
ole2.dll	 2.30.200.0
ole32.dll	 4.71.3328.0
oleaut32.dll	 2.40.4275.1
olecnv32.dll	 4.71.3328.0
olepro32.dll	 5.0.4275.1
olethk32.dll	 4.71.3328.0
rpcltc1.dll	 4.71.3328.0
rpcltc5.dll	 4.71.3328.0
rpcltccm.dll	 4.71.3328.0
rpclts5.dll	 4.71.3328.0
rpcltscm.dll	 4.71.3328.0
rpcmqcl.dll	 4.71.3328.0
rpcmqsvr.dll	 4.71.3328.0
rpcns4.dll	 4.71.3328.0
rpcrt4.dll	 4.71.3328.0
rpcss.exe	 4.71.3328.0
secur32.dll      4.10.0.2177
stdole2.tlb      2.40.4275.1
stdole32.tlb     2.10.3027.1
storage.dll      2.30.200.0

This table lists the version numbers of files distributed with 
DCM95CFG.

dcomcnfg.exe     5.00.1603.1
ciscnfg.exe      4.71.2618.0
