From:	MERC::"uunet!WKUVX1.BITNET!MacroMan" 24-FEB-1993 00:25 24-FEB-1993 00:25:00.00
To:	uunet!"macro32@wkuvx1.bitnet"
CC:	uunet!JON
Subj:	Windows NT terminology for VMS gurus

Windows NT terminology for VMS gurus.

Although this isn't strictly VMS internals, I thought that many
people on this list would find the following interesting.

Windows NT was heavily influenced by VMS.  These are some of my
observations from reading "Inside Windows NT", ISBN 1-55615-481-X.
This book is worth reading if you are interested in an overview of
Windows NT internals.  It is NOT at the level of detail that the VMS
IDSM.  If you are expecting that you will be disappointed.

After reading the book, I wonder how much of NT is really NEW
technology.  To me it looks more like a mix of VMS, Mach, OS/2,
Windows and DOS.

If these analogies are inaccurate, or have additions, please let me
know, and I can summarize.

Jon Pinkley  jon@clevax.wec.com

======================================================================

The following are not equivalent, but are similar in function.

VMS Terminology                         NT Terminology
---------------                         --------------

IPL (Interrupt Priority Level)          IRQL  (Interrupt ReQuest Level)

spinlock                                spin lock

IRP (I/O Request Packet)                IRP

ISR (Interrupt Service Routine)         ISR

Fork Process                            DPC (Deferred Procedure Call)

Fork Block                              DPC object

Fork Queue                              DPC queue

UCB (Unit Control Block)                Device object

DDB and possibly DPT                    Driver object

SCB (System Control Block)              IDT (Interrupt Dispatch Table)

CRB (Channel/Controller Request Block)  Interrupt object

channel                                 file handle

Global/Private Section                  section object

RTL (Run Time Library)                  DLL (Dynamic Link Library)

AST (Asynchronous System Trap)          APC (Asynchronous Procedure Call)
                                        NT APCs are limited to kernel and
                                        user modes.  It is not clear to me
                                        whether user mode APCs are capable
                                        of interrupting a user mode thread.

ACL (Access Control List)               ACL

PFN database                            Page Frame database

---------------------------------------------------------------------------

The following are less similar in function than the above

VMS Terminology                         NT Terminology
---------------                         --------------

Logical name                            Symbolic link object

Event flags and lock manager            Synchronization objects

XQP, ACP                                File System driver
                                        NT handles this is a layered fashion.

=============================================================================


Jon Pinkley   jon@clevax.wec.com