To:    Chris Smith
       Sarah Roe Centre
Fax:   7600799

From:  Jonathan Harston
       AFE Computer Services
Fax:   +852 850 4555

Date:  01-May-1993

RE:    Accessing a DOS partition from PCEm over the network.


Quoting from the RISC-OS 3 Release note (3.11):

"The new version [of the AUN/Level 4 fileserver] will also allow access to
PC partitions over the network"

  The older level 4 software allowed access to a DOS partition on the
fileserver, but only one client could use it at a time.  This is because the
partition is just another file, that the PCEm opens and accesses.  RISC-OS 2
had no knowledge that it was any different.  Opening it for read/write
denies anyone else (including the same person) access to open it again.  I
know this, because I did this at Stirling.

  However, the release notes seem to suggest that the AUN/Level 4 server
running on RISC-OS 3 (which you have) can recognise the DOS partition file,
and instead of opening it as a normal file, goes 'inside' it using the
server's DOSFS and allows clients access inside it.  I'll need to
investigate this further (next Saturday), but it seems to contain the
promise of running PCEm on many stations at once, all being allowed access
to the same DOS partition on the server.

  SerialUtils 'Problem':  Apparently, the SerialUtils modules does not fix a
problem in RISC-OS 3.  The rules governing the use of the serial buffer
vectors used to be more tolerent of applications using the vectors in ways
not explicitly stated in the 'rules'.  RISC-OS 3 has tightened up those
rules, so some applications won't work properly.  The SerialUtils module, in
effect, untightens those rules to allow the applications to run correctly.
It's not really a case of a problem with RISC-OS 3, but with applications
stretching the guidelines.  Like something expecting to be allowed to use
'*B.' to mean '*BASIC', when '*B.' really means, 'the first * command
beginning with B that matches'.



Jonathan