[Linux-decnet-user] Re: DAP , was Hello

[Patrick C. <pa...@ty...>]

On Mon, Apr 05, 2004 at 02:07:23PM -0400, David Mitton wrote:
> 
> Yes, we tried to fix a number of problems post 5.6. Versions 6.0 and v7.0 
> were major upgrades in the protocol.  However, many of changes were not 
> implemented mostly due to interia and backwards compatibility.  VMS would 
> have done the most work, as it was the most active in adding new 
> features.   Though the PATHWORKS (and Ultrix) development did expose issues.
> 
> The latest spec would at least provide insight into the correct approach to 
> problems or encodings not mentioned in v5.6.
> 
> Where do you want the files?


email to my above address would do, if you want an ssh logon I can open up my
public machine - send me an ssh public key.
 
> ...
> >
> >> - I was also the designer/implementor of DECnet-DOS and it's
> >> kernel.  Though the neurons are a bit rusty, I used to do a DECnet socket
> >> programming tutorial at DECUS.  I don't know how well your sockets match
> >> ours, but I may be able to dig up some old material.
> >
> >Actually, one of the DAP incompatibilities is with DECnet/DOS :-)
> 
> Nahh!  Not possible. ;^)
> One of the best NFT implementations out there.
> Seriously, if it's not a bug, maybe it's a mis-understood or undocumented 
> feature.  DEC filesystems can be interesting creatures.

Oh, I'm pretty sure it's a bug on my part. I do some pretty dangerous things
with the CONFIG message to try and make things nice for VMS users and it
wouldn't surprise me if I've overdone it.  I'm also fairly sure that FAL sends
far too may ACKs in some circumstances.

> Another "feature" of DECnet-DOS was that we wrote a DOS block device (disk) 
> driver (NVD) that did a DAP open to a FAL of a file for random access in 
> Block mode or Fixed:512 and created a DOS virtual disk using DAP 
> protocol.   Only drawback is that DOS block operations are not optimised at 
> this level.  Performance could suck big time for disks with large 
> directories.

From what I remember DOS block operations were not optimised at all!
 
> But it worked for simple xfers if you didn't have an SMB server installed.

One thing I wanted to do for Linux, but never got round to it, was a libc
interceptor that took filenames with "::" in them and sent them over the network
to a DAP server so Linux could have proper transparent file access...I may yet
do that but I subsequently worked out just how many library calls I'd have to
intercept :-)


patrick