Path: utzoo!attcan!uunet!wuarchive!brutus.cs.uiuc.edu!tut.cis.ohio-state.edu!ucbvax!VAX.FTP.COM!jbvb From: jbvb@VAX.FTP.COM (James Van Bokkelen) Newsgroups: comp.protocols.tcp-ip.ibmpc Subject: Re: LAN Manager (was PC/NOSs) Message-ID: <8909271548.AA05302@vax.ftp.com> Date: 27 Sep 89 15:48:16 GMT References: <8909261939.aa15775@Obelix.TWG.COM> Sender: daemon@ucbvax.BERKELEY.EDU Organization: The Internet Lines: 36 One major problem with LAN Manager is that its only programming interfaces are the "Named Pipes" and Netbios NCB interfaces. There is no defined method of getting at an unadulterated transport protocol connection; whether the transport is XNS or TCP or OSI the lowest you can get is a Netbios session. So the LAN Manager "standard" can't talk to anything except other LAN Managers or Netbioses without vendor extensions (which won't be standard unless/until the market produces one). Furthermore, there is no defined interface to the redirector, so any filesystem sharing you do uses SMB. No Netware, NFS, RFS or RVD under LAN Manager, unless you want to hide a kludge that translates SMB to another protocol below the pseudo-NETBIOS layer (not if I can avoid it). In terms of layering, NETBIOS is more or less session-layer by itself. It can be defined to use different transport layers (TCP, XNS, OSI, DECNet, etc). Transport layers can use different MAC layers, but it is hard to make a particular instance of a transport layer independent of the MAC layer below it; Ethernet uses ARP one way, 802.5 uses it another, MTUs and headers differ, bit orderings differ. Neither NDIS, ASI, Packet Driver or OLI provide real MAC-layer independence; instead they provide demux support and independence from details of individual Ethernet (or whatever) cards. IBM's ASI interface is very 802.5-specific, but the others aren't specific to one MAC layer. Fundamentally, LANManager is Microsoft's idea of what a NOS should look like, complete with solutions for all the problems they felt were important, tailored for the operating systems they care about. As such it is different from SNA/SAA (IBM's idea), DECNet (DEC's idea), Netware (Novell's idea), etc. etc., but no less proprietary and narrowly-focussed. The open standard you would probably prefer doesn't really exist yet, but Apollo/HP (with NCS), Sun (with their RPC and Yellow Pages) and the OSI people are all heading that way. James B. VanBokkelen 26 Princess St., Wakefield, MA 01880 FTP Software Inc. voice: (617) 246-0900 fax: (617) 246-0901