Convert from ODS-2 to ODS-5

[Michael D. Ober]

Would these differences also improve directory access in Samba?  Samba 2.2.4
is extremely slow during directory searches on our ODS-2 based systems.

Mike.

-----Original Message-----
From: jean-yves.collot at cofiroute.fr
[mailto:jean-yves.collot at cofiroute.fr]
Sent: Tuesday, September 24, 2002 10:38 AM
To: Samba VMS
Subject: RE: Convert from ODS-2 to ODS-5 


What are the benefits of converting from ODS-2 to ODS-5 ?...

First, you must be aware that Samba/VMS 2.2.4 is only supposed to support
ODS-5. Actually, there was no real tests done...

Well, now. How Samba deals with file names ?
There are 2 problems : first the VMS unsupported characters in file names
(é,à,blanks, etc..) and second the looooong file names. As you know, VMS
accepts a maximum of 39 characters for the name and 39 characters for the
type.

For Samba 2.2.4, I took the solution designed by older Samba/VMS ports, and
I added a little more, in order to be fully compatible with Pathworks. When,
for some reason, a character is not acceptable in the file name (a blank, or
a second dot, or some "ôther" char, it's replaced by it's ASCII
representation (in hex), with "__" before it. As an example, "hellô.txt" is
seen on VMS as HELL__93.TXT. In addition, if the file name or the file
extension is greater than 39 characters, everything is considered as a
single entity : the "real" dot (if any) is encoded as __2E, and I put a dot
as trhe 39th character, and this dot is not seen from the client PC. For
those who are interested, you can study the details in CVT_FILESPEC.C

OK. So the drawbacks are :
- suppose you want to have a file named A__20B.DAT. You'll always see it as
"a b.dat" on your PC
- There is no way to name a file "Hello.txt" : it will always be seen as
"hello.txt"
- the 39/39 limitation is always there, even with the tricks I listed above.
In addition, remember that the "special" characters are seen as 1 char from
the PC, but actually take 4 chars (__xx) on VMS, so the real maximum is NOT
39+39 seen by the PC, but may be far less than that (depends on the number
of "special" characters).
- VMS applications wanting to share files with PC applications must be aware
of the above tricks (if those PC applications use fancy names...)

With ODS-5, all this disappears, and you can have a file named "Once upon a
time I walked happily in a beautiful  forest" on your VMS machine as well as
on your PC, and you even can share it between 2 cooperating applications...